Big Fat Dummy: Make It An Ebike

What is necessary to transform a Surly Big Fat Dummy into an electric bicycle? I thought my BFD series was finished until I realized I left this part out.

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar.
Episode 5: Leftovers
Episode 6: Electrification (You Are Here)

Oops?

On the surface, it seems I left a hole in my description of my Surly Big Fat Dummy build. I omitted this episode and thought I was done. In my defense, there are zillions of BBSHD installation tutorials out there, and I have described a BBSHD install myself – on a cargo bike no less – right here in this blog.

However, I haven’t done a writeup geared to THIS bike. Since this blog is dedicated to answering questions that I see asked a lot (and I have seen this one more than a few times), I’ll do something a little more focused on the BFD.

Bear in mind the bike has been in near-daily use for months already. I had to dig thru my archives for pics rather than taking them as I went along. So illustrationwise, there’s not much to see. On the flip side of that, there doesn’t need to be as the Big Fat Dummy is an easy (easy!) build.

Since I have covered this ground elsewhere, I’ll be leaving generic details out, and providing links to related content more so than I will be doing in depth step-by-step instructions.

Get On With It Already!

Yeah, yeah sure … here we go.

Step 1: Buy What You Need

This can be very simple or very involved. Especially if you are a first-timer and don’t know what you need and maybe not even what you want. In my opinion the best motor for the job is a Bafang BBSHD. I typically buy my motors from Luna Cycle, and here is their page for their kit. They may or may not be selling a battery along with that kit. I am using a different source for the pack as you will see further below.

If you buy the kit, you don’t have to worry about buying individual bits, with the exception of needing a speed sensor cable extension, and a proper chainring.

But, lets go over the individual bits. Myself personally, I just buy the bare motor from Luna, and add the parts I need to complete the installation. This lets me use exactly what I want, which is not quite possible if buying the packaged kit. Here are all my parts:

  • Bare Motor:
    Purchased from Luna Cycle here. The Surly Big Fat Dummy requires the 100mm sized motor (It will be a perfect fit). if its available you can buy the optional spacer and mounting kit on that page. At the moment, Luna is not selling the 100mm mounting kit – the only difference is some M6 bolts and spacers… you can source that yourself to the correct size if needed. Or just buy the needed parts separately. Go ahead and accept the 46T chainring (aka ‘The Disk of Death’) as its a free throwaway item you would (should) never use.
    Secondary Source: California Ebike is a reliable alternative and one of my go-to sellers for parts, but their motors cost an additional $100 or so. Here is their BBSHD motor page.
  • Motor Mounting Parts:
    • Triangle Mounting Plate:
      This is what puts the bite on your bottom bracket to firmly affix the motor. You can buy these plates at Luna Cycle, BafangUSA Direct or Amazon.
    • M6 bolts, washers, spacers:
      Needed to affix the Triangle Mounting Plate, these are commonly available. If you work on bikes you probably already have them in the garage. If you buy a mounting kit they may have them but in all cases I recommend you do not use them and instead go out and buy stainless hardware.
    • Lockrings:
      I use two inner rings stacked atop one another. If you like, you can buy the more conventional inner and the aesthetically-pleasing outer. More on the reasoning behind the choices below. Buy the rings at Luna Cycle, Bafang USA Direct or Amazon.
  • Speed Sensor & Cable Extension:
    You will need the sensor (which integrates a length of cable to plug into the motor), the sensor magnet and an extension thanks to the Surly Big Fat Dummy’s long tail. I have seen builders route the sensor to the front fork but by necessity this puts the sensor inside of the tire rim’s width, which makes for issues taking that tire off. Put it on the back where it belongs and forget about it. I described the sensor in a fair bit of detail here. Don’t mess with multiple magnets unless you feel a need to experiment, but I do provide a link to what I think is a lighter weight, superior magnet that you may want to substitute for the Bafang wheel weight that comes with their sensor. The speed sensors themselves are available in a wide variety of places, cheapest at Luna but also at California Ebike and many other sources. You can get the speed sensor extension anywhere you can find the speed sensor. California Ebike or Bafang USA Direct or many other sources, including Amazon with Prime Delivery. Notice all of the options I linked are different lengths. Measure the gap you have when you are routing your cabling and decide which one you want, accordingly.
  • A Proper Chainring:
    I am going to skip most of the detail here and refer you to this blog post on BBSHD chainrings. It was written with the Mongoose Envoy build in mind but the Surly Big Fat Dummy is essentially an identical set of problems and solutions. I will say this: For a combination of mostly street with some mild trail use I settled on the 46T Lekkie Bling Ring, which biases chain line towards the bottom half of the 11 speed cluster. This is the ring that has the most miles on my bike and its the best all-rounder. At the moment I am set up mostly for trails, though, and as such I am running the Luna Eclipse 42T which biases chainline heavily toward the inner half of the rear cluster, giving me good access to the inner cogs. You cannot go below 42T in the front without compromising chainline to the inner cogs.

    Note with a BBSHD, the stock My Other Brother Darryl rims and the stock Edna tires, you will not be fully able to use all cogs simply because chainline will not be acceptable for a 1x drivetrain pumping out 1000 to 1750w. You8 can do it, but the chainring teeth and maybe the chain will not last very long if you run at either extreme – say… the biggest cog and the Lekkie chainring.

    Two of the pics below show a 130 BCD adapter which really biases chainline to the lower cogs, and is best for the street. Both of these use 48T, 130 BCD chainrings. Even though most of my mileage on this bike is with the Lekkie ring, it doesn’t appear as if I ever took a picture of the bike with the thing installed.
  • Crankarms:
    In two of the pictures above you can see I used Lekkie Buzz Bars, and with their forged construction and left offset to correct the misalignment under your saddle that will happen with standard crankarms. Luna Cycle sells a less-expensive clone worth looking at if you can’t handle the price of the Lekkies. As a last resort you can also use the standard Bafang crankarms that are cheap and cheaply made, but good enough for many riders. Make sure you buy BBSHD-specific arms or they will not have the left offset.
  • Display:
    I have used many displays and hands down, at the present time the Bafang/Luna 860C is the best out there. It is fully visible in blinding sunlight and can be set to display both real time amp output as well as real time wattage. The Luna version reads battery voltage level accurately up to 60v, meaning it works with 52v batteries. Bafang versions of the 860C may not. There are many other options for a display including a low-visibility-but-clean/low profile EggRider v2. For my money the 860C is worth waiting for if its temporarily out of stock, and its my go-to for bikes I build.
  • Throttle:
    I like the basic el cheapo Bafang universal thumb throttle. Its an easy fit and unobtrusive. If you follow my lead on BBSHD settings for it, its annoyingly short throw will still be well controllable and allow for fine adjustments while riding. Buy it at Luna, California Ebike or Bafang USA Direct.
  • Main Bus Cable:
    You have options here. the main bus cable is available in short and long lengths, and there are also extensions available. However nothing fancy is required on the Surly Big Fat Dummy. You can buy this standard one from Luna or many, many other sources. If you opt to use Magura MT5e brakes, California Ebike has a specially modified harness to plug in the red Julet cutoff connectors the MT5e uses. I am using this bus cable and MT5e’s, myself. NOTE: If you opt to keep the SRAM hydraulic brakes you will not have brake-actuated motor cutoffs. This is no big deal. They’re nice but the stock brakes can overpower the motor in a pinch. If you like, you can invest in some hydraulic cutoff conversions that involve gluing on a magnet to your levers and strapping on some wires. the alternative is a brake upgrade (not a bad thing, but not cheap, either).
  • Installation tool(s):
    Using one of the many Bafang-inspired toy wrenches to install a BBSHD is a cruel joke on the inexperienced. You have to use a proper torque wrench and special socket to do the job right, where the motor doesn’t move. I’ll leave the torque wrench choice to you (I use a Wera B2). The socket you need for the inner ring is often out of stock. Buy it here at Luna Cycle or hunt around… its available elsewhere if you look. The tool for the outer ring can either be hand-tightened – if you must – with a stainless steel version of the cheesy Bafang wrench. I bought this one on Amazon so I know it fits. But it is absolutely a sucky solution. Better is to use a 16-notch bottom bracket tool that you can fit onto a torque wrench and do a proper job of applying the manufacturer’s torque spec, written right on that outer ring. Note if you use two inner rings you do not need the special outer ring tool.
  • The Battery:
    There are a bunch of different ways you can play this. Among others you can plant one on the bike on the framework just behind the seatpost. At present mine is in the triangle in a bag. My seize Medium frame can just barely hold this 21ah, 52v battery from Bicycle Motorworks. ‘Barely’ means after I have added some padding. I also keep the battery in a quick-detach bag inside the triangle. I described the quick-release setup with pics in detail here.

    I’d like to have more room for padding, so I am exploring a shift to that framework as an alternative. We’ll see as its a big change.

Step 2: Remove Stuff

OK so you have all of your parts for the motor… Time to take things off so you are ready to do the installation. Its a simple list: Remove the crankarms, bottom bracket and chainrings.

You’ll also want to pull off one of your handlebar grips in preparation for installing your throttle. Which one depends on how you want to set up the bars. You will also likely want to loosen up and shift around your brake levers and the remaining rear shifter so your throttle is butted up directly against your hald-grip, rather than the brake being there. this is a bridge you should cross when you come to it, disassemblywise.

Initially I used a Luna Wolf Pack, as shown in this picture. Thats another option for your build.

Thats it. You’re ready to install your motor.

Step 3: Install The Motor

Here again I’m not going to get too deep into the specifics of motor installation. I’ve already covered it myself elsewhere for a similar bike, and God knows there are plenty of video and written tutorials out there on the interwebs. However I will note that the 100mm motor is a perfect fit on the Surly Big Fat Dummy, which requires no spacers of any kind. Just put it in like it belongs there and clamp it down tight.

About that clamping part, I will go into that a bit:

Lockrings

I mentioned above that I like to use two inner (gray) lockrings: I stack them atop one another in jam-nut fashion where each is tightened to 100 ft lbs. Thats quite a lot more than the Bafang specification for using just one inner lockring. I am going off of installation advice provided by Luna Cycle – not in their official installation video linked above. At one time there was a supplemental vid made in their shop that discussed their learning to do this on their shop bikes. It went hand in hand with the use of a big 1/2″ torque wrench to apply the necessary force, and that wrench in turn used a specially made Luna tool for the lockrings (that sadly is no longer available, although you can see them on the site still). The use of 100 ft lbs and some additional info on it is in the link to the tool above.

I have stuck to that 100 ft lb specification and it has never let me down. I have also added to it by using a second inner lock ring rather than the ‘beauty’ trim ring that is more typically used. the number of threads needed for another inner ring is about the same. You gain the benefit of a serious jam nut holding down the first ring. Also, something we are not doing here but you can see elsewhere: If you are building an AWD bike, the use of two rings lets you mount the front wheel’s PAS ring in between the two.

I do not use the outer trim / beauty ring at all.

Lastly on the subject of lockrings, here’s a technique to tell at a glance whether the rings are loosening or your motor is shifting (or about to): Make a registration line along the frame and the lockrings. If the line ever breaks apart, something is loosening. You can tell with a simple glance down as you are mounting the bike.

See the registration mark (aka the black Sharpie line)? Also note there are no spacers needed on the locking plate under the M6 bolt on the left. Perfect fit for a 100mm motor.

Next, I’ll make note of how I did the speed sensor installation, both with the factory SRAM brakes and my later MT5e upgrade.

Using the SRAM Brakes / No Helpers

Attaching a speed sensor on a Surly Big Fat Dummy is not as straightforward as it is on a typical bicycle. In addition to the added distance – addressed with an extension cable – there’s no place to put the thing! The frame is different enough that nothing appears to work – on first glance.

Keep looking! the SRAM brakes that come stock with the bike have a weird sort of tail hanging off the caliper, and this is a handy, if unusual, place to mount the speed sensor.

I first wrapped this tail with a length of 3M mastik tape to enlarge its diameter and give the sensor more to grab onto. Then I simply zip tied it on as if it were a chainstay, and aligned the magnet as usual. These pictures show a dusty bike as they were taken just before I uninstalled the sensor and upgraded the brakes to the Magura MT5e’s.

Using Other Brakes – And a Crutch

For the Maguras, there was no such luck as the calipers have no tails or anything else I could glom onto. So I had to add something: I used a simple small handlebar extension, and built up the frame to a proper larger diameter to mount it by wrapping the frame with gorilla tape, which I then faced with silicone tape to provide a grippy surface for the bar mount. Next, I used more zip ties (!) to clamp the new ‘frame tube’ to the upper part of the Big Fat Dummy’s … superstructure. Once this was done, I had a tube close enough to the spokes to re-mount the speed sensor as shown.

What About a Gear Sensor?

Good question. Read this.

Whats With The Heat sinks on the Motor?

I’m glad you asked. Here’s your answer :-).

What Else?

Well, a bunch I suppose if you were looking for a bolt-by-bolt conversion tutorial specific to this one bike. But really, between the other pages already on this site and the links I have given off-world up above, you’ve got everything here that you need to buy – and build – your own.

So have at it!

Big Fat Dummy: Leftovers

We hit the high points of the Surly Big Fat Dummy build. Lets wrap it up with a discussion of some odds and ends

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar.
Episode 5: Leftovers (you are here)
Episode 6: Electrification

Basket-Case Handlebars

One of the most notable features of this Big Fat Dummy are its handlebars with the integrated basket made of thick, hollow alloy tubing. At first glance, these are nothing more than EVO Brooklyn integrated-basket handlebars. Here’s a factory-stock picture of them.

Now lets take a look at the ones on my Surly Big Fat Dummy. Notice a difference?

Figure 1. Hint: Look at the grips

The grips give it away: I extended the handlebars so now they have a width of about 810mm. I am using ESI Extra Chunky 8.25″ grips to cover the extensions and give me an extra-long gripping area, suitable for multiple hand/seating positions (choke up and hammer it, sit up and cruise). Just like on a pair of Jones bars, the brakes can be reached from any position on the handgrip.

The grips give something else away: the bar extensions have a smaller diameter than the stock handlebars. At first I planned to use the extension you see in the pics below as an internal sleeve coupler between another bit of tubing, the same outside diameter as the handlebars. After seeing it in place and thinking this ‘coupler’ had potential on its own, I covered one side in a grip to see what it felt like. The two diameters worked for me and I decided to stop there.

I like the lesser diameter as a sort of change to the handhold. Good for longer rides where I want to vary my grip to reduce fatigue. The wide outer hold is better suited to comfy cruising anyway, so between that and the added thickness provided by the fat ESI grips: The lesser diameter section feels normal. The point of transition between the two diameters is also another form of handhold variation. It is just one more way to grip the bars differently on a long ride to change up what part of my hand is getting pressure.

What about the bar extensions themselves?

They are a bit of aluminum bar stock whose outside diameter is very near that of the inside diameter of the handlebars. Some fairly pricey stuff can be found at specialty hardware sites. I stumbled upon pre-cut bar stock with the right OD; already cut in the perfect length, so I didn’t even need to put a saw to it. (I did chamfer and bevel the inner and outer edges with the same tool I list in the Big Fat Wideloaders post). I bought two of these and that part of the job was done.

Specifically, the material is 6061-T6 aluminum bar with a 0.625″ (5/8″) outside diameter, a 0.375″ inside diameter (0.125″ wall thickness). Each bit of tubing is 10″ long. On the off chance its a link that will live on (its live as of today, several months after my purchase), here is what I purchased.

How did I affix it inside the handlebars? A combination of things hold these extensions firmly in place:

  1. The inside diameter is a close fit but not a tight fit. I wrapped a single layer of silicone tape around the inner bar in two places with a gap of a few inches in between. Just enough to make it a seriously tight fit.
  2. I spread/glopped some JB Weld around the outside diameter of the inner bar, in between those silicone tape wraps, before insertion. That makes for a bit of a seal for the application of the JB Weld and ensures during insertion it builds up into enough to fill the gap between both bars.
  3. I inserted the bar fully and then used a 2-lb sledge to make sure it was for-sure seated inside the handlebar.
  4. Stretching/installing the ESI grips over the assembled, extended bars provides, in and of itself, a strong hold that prevents movement.

One last note: Even at an 810mm width and extended grip length, the ESI grips are just a skootch too long for this bar, considering the controls I have to mount on whats left of its straight portion. I turned that bug into a feature. The ESI grips are so substantial they are good as bumper pads. To supplement that, I tightly rolled up some white silicone tape (the same stuff I used in giving the bars a tight fit) and used that as a bar end plug. The roughly 3/4″ of overhang is now a substantial padded bumper, useful when I am leaning the bike up against something. You can see the bumper in Figure 2 below.

The Double Stem

Figure 2. Going up. The stems are angled up in this pic for an elevated bar orientation.

Wait… what? A double stem? What the hell is the thinking behind that?

So, here I am building out this Big Fat Dummy with these basket-case handlebars. I have used them before, on Frankenbike. On that bike, the bars could shift down if you were standing up, honking on the pedals and putting strong downward pressure on the bars. Knowing this can happen, how can I get around it? Would using a higher quality MTB stem do it? Then I realized a)I had an uncut steerer on my Bluto fork and b)the handlebars have two mounting points in their design.

The idea was to use one or the other. But that long uncut steerer might just let me use both (spoiler alert: it does).

So, as usual I tripped and fell into a functional and eye-catching solution. Use varying spacers in between the two stems so they space apart exactly to fit the two mounting points. The lower 25.4 stem mount point needs a 31.8 spacer around the bar. Also, the easiest way to limit the variables in play is to use identical-model and -angle stems and simply vary their length. I used Funn Stryge stems in 60mm and 80mm.

In Figure 2 above I have angled both stems up, giving the most upright position possible. Later on, I flipped the stems to a down position to give more lean-over (clearly these bars have a significant rise built into them so seating position is still fairly upright).

Figure 3. Going Down. Both stems are mounted upside-down for a lower handhold. Just reverse the front plate so that part is right-side up.

In my final tinker with the stems, I changed their orientation once again: The lower stem is still pointing down, but the upper one is pointing up. This still keeps the bars oriented in the ‘down’ lean-over position, but the position of the upper stem moves further down the steering tube to achieve the same bar angle it had when it was matching the lower stem as seen in Figure 3.

Whats the point of doing that? It uses less steering tube. As you can see in the pics above, I am using 100% of the Bluto’s uncut tube. Making this flip and exposing more available steering tube enables a change to a Wren Inverted fat fork, which reportedly had a shorter uncut steerer…. with this change I would use 100% of the Wren tube, should I ever find another home for the Bluto.

UPDATE:
The Bluto did find a new home and the Wren is on the bike now... I compared them while I still had both in hand and both forks have identical steering tube lengths.

Reinvented Wheels

The Surly My Other Brother Darryl wheelset that comes with the Bliolet Big Fat Dummy is very good. It can take quite the beating. I certainly have never been able to throw either of them out of whack. However, I wanted summer and winter wheels, the ability to go tubeless, and have wheels as strong as possible. Additionally, the MYOBD wheels hold on to tire beads so tight it is effectively impossible to get at a tube to repair it on the side of the road. That had to change.

SIDEBAR: If the MYOBD rims are tubeless-compatible as claimed by Surly, mine certainly are not. The rims are pinned and not welded. And both of mine leaked at the pinned seam on the edge just under the bead – a place you can’t tape. I personally don’t see how they can be used tubeless unless you get lucky and those pinned rims are perfectly manufactured. Mine were, and are, great tubed wheels but they can’t be used tubeless even when its been done by professional LBS techs who know what they are doing. I failed. They failed. The rims don’t work tubeless.

With that said, lets focus on the wheel build. I settled on the following components:

DT Swiss 350 Big Ride hubs

The DT Swiss 350 Classic is just that. A reliable classic. In particular, the rear hub is acknowledged by DIY builders as extremely durable when paired with a high powered mid drive. Couple the ratchet engagement mechanism to the steel cassette body option that DT offers and you have the core components of a bulletproof drivetrain. DT even makes the 350 Hybrid hub that is reinforced still further for tandem and ebike applications. Sadly, its not available on the fat bike Big Ride variant. But a plain 350 with a steel body is still unstoppable. I know because I have used one on my 2Fat build for some time. The 2020 parts shortage made finding a front and rear hub an adventure – I got the rear in Poland and the front from the U.K. … But I got them.

Alloy on the left after 1500 miles. Zero miles and steel on the right… After 2 years it still looks that good.

Nextie Wild Dragon II Rims

This was a tough one. These are expensive hoops at over $300 each. However, they are also a known quantity as I own another set on the Stormtrooper (those wheels with their matte 3k finish are the header image for this blog). The standard version (not the Elite light weight) have a load capacity of 250 kg.

As far as I can tell, nothing else on the market can touch that load capability. Also, they have a center channel I know from experience makes ALL the difference between getting the tire off the rim on the side of the road, and not being able to do so (that would be the case with the MYOBD’s). Lastly, they are a nice compromise of 90mm, which I hoped would allow me to lose only the highest rear cog on my 11 spd cluster. Turns out that was a correct guess. Others who go 100mm lose the top two.

The Nexties check all the boxes. It boiled down to whether I was willing to spend the money. After some time hemming and hawwing, I surrendered and spent the big bucks.

<takei>”Ohhhhh Myyyy” </takei>

I did 3k matte finish last time. This time I upped the bling factor – just a bit – and went 12k matte. And holy cow are they ever gorgeous. They fit the bike perfectly with that deep dish construction making the fat tires the fattest fatties in Fatland. As it is, this beast of a bike already makes a serious visual statement. The wheels dial the message volume to 11.

With the above said, you might be under the impression that the look of these wheels contributed to my buying decision. I am outraged anyone could consider such a thing.

In addition to looking marvelous, they’re waterproof too!

Sunrace CSMX8 Wider Range Cluster

The original Surly-spec’d cluster is a Sunrace CSMS7 11-40T. Even though the Surly BFD is not sold as an ebike, that is the perfect 11 speed cluster for one. It is all-steel, bolted together into a single 1-piece unit and has steel spiders inside. As usual the heavier, cheaper steel component is the good one if you have an ‘e’ in front of ‘bike’. Finding an 11-42T version of that cluster would have been perfect… but alas thanks to the 2020 parts shortage, I couldn’t get my hands on one. I settled for the CSMX8, which is 11-42T and also uses steel cogs. Its in 3 pieces and uses alloy spiders. Not ideal on a mid drive, but its still a respectable bit of kit. Why did I want a wider range cassette? because I knew other Big Fat Dummy riders who went to wider rims and tires lose their two biggest cogs. Expecting this, I wanted the biggest cog I could still get to. So: wider range cluster.

As it turned out, the 90mm rims and 4.8″ Vee Snowshoe XLs only cost me one cog. So while I cannot use the 42T cog without rubbing, the 36T just under it is no problem. That means I only lost four teeth off of my former 40T inner cog, and I have a 10-speed instead of an 11. I’m fine with that.

Sapim Strong Spokes

Here is the one place I compromised. I wanted DT Champion 2.34 spokes. In the age of lockdown-induced bicycle parts shortages, that was just not happening. Nobody had enough spokes in the three lengths I needed … worldwide. Actually I did find stock in a bicycle shop in Germany but they refused to ship to me because of the then-severely-extended ship times of 10 weeks-plus. DT Swiss themselves said forget about it until at least 2021. Casting about, I talked to other strong players including Phil Wood. Every time, I struck out. Eventually I did find a small local bike shop in another US state who had Sapim Strong spokes and could cut them to the sizes I needed in-house. The 2.34 Champs would have been stronger, but the Sapim’s are plenty strong themselves. I don’t expect any issues.

Orange Seal Valves and Whisky Tape

Last but not least: The valves and the tape. Whisky tape is good stuff – a bit wider than most alternatives – and I was able to find a big roll, so I had plenty of extra socked away for my attempt at converting the MYOBD rims to tubeless (which as noted above… failed). I chose the Orange Seal 60mm valves because they have something a lot of valves do not: A metal bottom. Why? the metal bottom provides a hard surface that the valve gasket can firmly smoosh up against. There’s no way for the valve to pull thru. Its also less likely to spring a leak down the road when you manhandle the valve putting air into the tires. This last issue plagued my Stans valves on a different bike, until I replaced them with these.

You get everything but the kitchen sink in the bag with the Orange Seal valves, including a nice core-remover that screws onto the valve itself so it can’t get lost.

Phat Tubeless Tires

So… on this bike… tubeless is where its at! The Nextie rims coupled to Whisky tape seal right up. The Vee Snowshoe XL’s I put on (I have had them in the garage for a couple years and it was time to use them up) sealed to the rims so well I didn’t really need any sealant to finish the job. They held air for days as-is.

But of course I used sealant. And as I have mentioned in earlier posts, after discussion with the manufacturer and some great experience with it as a tube sealant, I used the recommended 16 oz(!) of FlatOut Sportsman Formula as my tubeless sealant. Application is easy via adding a presta adapter to the end of the integrated hose in the bottle lid. Once in the tire, they hold air for about… 5 (five!) weeks before its time to air up again.

And since I set these tires up, after a few months, I had the worst-case experience with respect to finding out whether FlatOut actually works to seal up tires.

Want to see a cyclist poop his pants? Punch a line of a half dozen of these in his back tire. Then tell him to hop off the saddle and go look…

Yeah thats right. So I go to Home Depot and load up on all sorts of crap. My Great Big Bags as well as my upper deck are pretty much full and I am chugging home. Suddenly I hear a tickticktick behind me and I know thats not good. I jump off, look down and OH.MY.GOD I see a row of about six roofing nails stuck deep in my back tire. As if thats not bad enough they are off to the side in the vicinity of the sidewall (the ticking was a nail head hitting the frame as the wheel revolved). Not thinking to save the nails for a future photo shoot, I pulled them out and cast them away. When doing that I saw the tire knobs pull away from the tire thanks to the damage from the nails and of course the hissing got worse. Having lots of sealant in the tire, I did what I could to lean the bike over on the side with the holes and roll it down so the goop could glop into the holes and save my bacon.

The hissing lessened but didn’t go away.

26×4.8 tires inflated to a street-legal pressure of 18 psi have a lot of air to give, so I jumped on the bike and got rolling fast; again with the idea of letting the sealant spread and seal. I got maybe a block before the lessened but continuing air loss meant it was time to stop and refill. Here’s where having the lightweight, emergency electric bike pump made all the difference. In short order I had the pump connected to my tire and battery and it began noisily refilling the now almost fully flat tire. Once the tire got reasonably firm I disconnected, stuffed the pump into the kangaroo pouch and got rolling, all the while hearing hissing, still. I repeated this process two more times on the way home. After the third refill, the hissing stopped. FlatOut sealed a massive series of holes and today, weeks afterwards, the tire is still holding that same amount of air.

It remains to be seen if the tire can be considered reliable for long term, long range use. I have been riding other bikes in The Pacific Fleet recently until I can take the time to do a full post mortem. But bottom line: FlatOut got me home and averted certain disaster. It gets my enthusiastic seal of approval.

The Bag Bumpers

Problem: the Great Big Bags are so big, they exceed the length of the frame structure. The padding keeps them from flopping around, but they can still curve inward and, on the drive side, touch the chain which is very close by. That chain is a chain saw on the fabric and you’d better not let it contact the bag for long. Also in the rear the bags can be worryingly close to the tires – still 2-3 inches away but it would be nice for them to keep their distance period.

Solution: Re-purpose the existing M5 bosses that Surly used for the stock Dummy Bag mounts. Attach a 36″ metal strip, whose function is pretty obvious just looking at it:

Figure 1: Initial test fit. This fit uses smaller washers and the strip is upside-down as noted below.

Pretty straightforward stuff. Whats not so straightforward? I think Surly did a pretty solid job of engineering this frame so its sturdy where it needs to be and flexible when it needs to be. They don’t need me re-engineering the give and take this frame was designed to deliver under load. So the challenge is to create a rigid structure that keeps the bags from intruding into the wheel well, but at the same time does not provide unexpected structural rigidity.

A stiffer frame sounds great, until you realize you are adding rigidity selectively. If flex is a part of the frame design, then its going to happen one way or another. I would rather it be distributed as the manufacturer intended rather than restricting all of the forces to exert themselves in a new spot, in a way the designers didn’t anticipate.

So here’s how we do that: first and foremost, I drilled an oversized (M10) hole at the front anchor point. Additionally, I sandwiched the connection in front and behind with rubber washers that themselves are captured on both sides by stainless oversized washers.

That big hole is off center on purpose. You hang the strip so it lies roughly centered. Then it can still flex without hanging near its edge (Figure 1 is a test fit and its actually upside down in that pic).

Also note the steel washers above were swapped out for wider ones to fully capture that rubber washer in between.

Just an oversized hole doesn’t fully allow the frame to flex as designed. You need a long slot in the back to further allow unrestricted frame movement. I created this by hand using a time-tested – and ugly – method:

  1. Mark your material with a Sharpie.
  2. Drill a line of pilot holes with a small bit. Yes it looks sloppy.
  3. Drill out the pilot holes with a larger (M6) bit.
  4. Hand file to a squared-off rectangle slot. Not quite finished in the last pic at right.
  5. File the face of the strip on both sides to debur it after all that filing.

When done, bolt it on. If I had this to do over again I would add another half inch of play fore and aft just to be sure I achieved my goal here.

Yes, of course I replaced that rusty old bolt after this test fit.

The Inexpensive, Custom Frame Bag

Custom frame bags cost a small fortune. Mine cost me $40 delivered to my doorstep. I use a vendor on EBay named Uraltour. Four bags purchased from that vendor so far and all are sturdy, heavy cordura with perfect fit around existing frame bosses and whatnot. You can specify width and since I am buying bags that will hold 18650 battery packs, I insist on a 10cm width. Maybe you can get away with 9cm. Don’t use the default of 6cm unless you have different needs. He will also work with you for shapes other than triangles.

See the little red whatsit up front? Thats my charge cable with a waterproof cover. Ask for flaps top front and rear for cables.

The downside? Well, his business name provides a clue: He’s deep in the middle of Russia. So mailing stuff from Russia to the USA can take at least a month and possibly two. My first bag took three. But thats life. A USA supplier would have provided me with excellent bags, at a much higher price point. Oftentimes they are booked up and you’ll wait months assuming they will take the order at all. Not being able to get a US vendor able to take my order was what made me go looking for another source and finding this vendor.

The Shelf

The space just behind the top tube on the Surly Big Fat Dummy – just ahead of the rear rack supports – is wasted space. A few owners have had custom bags made for this area. I more or less built my own cargo shelf out of odds and ends.

  1. A small bit of aluminum flat bar stock roughly 4″x16″ (I forget the exact size… I had it in my garage from a previous project where I was making a rack floor for another bike).
  2. Another small bit of flat bar stock, about 4″ wide and 10″ long
  3. Leftover 3/4″ ID Silicone hose
  4. Some leftover Great Big Bag closed cell padding
  5. An M6 bolt, washers, a nut, an unthreaded spacer, four zip ties and some Gorilla tape.

Showing pictures of the thing make it pretty easy to figure out how I used the above parts.

The silicone tubing is used to pad the frame. Just slit it down the middle and fit it over the frame tubes. It’ll hold and stay on its own.

Look under the bolt on the crossbar. There’s a spacer with washers underneath so the bolt doesn’t just bend the floor plate up towards the frame.

The padding covers the big floor plate, and the gorilla tape covers that to make a big padded shelf base.

The smaller flat bar plate and zip ties make for a backstop for the shelf. Its sitting at an angle and the last thing you need is for your stuff to slide into the wheel well. I painted mine black but gorilla tape could be used on it as well. Drill 4 holes for the zip ties.

If you look over at the post on A Proper(e)Bike ToolKit – which spells out the BFD’s tool kit – the cheapie MOLLE bag I use there is sold in a pack of two. This is where I use the other one.

This is how I carry along my super duper Pragmasis hardened steel noose chain and U lock.

I keep the keys in the bag with the lock so I never forget them.

The Quick-Detach, Carry-On Battery

I wrote this up as its own separate thing. Check it out here.

Big(ger) Brakes

The SRAM brakes that come stock on the Surly Big Fat Dummy are good, but on a bike that can take on extreme loads and terrain, they need to be great. I literally use the same brakes on all my bikes.

  1. Magura MT5e 4-piston brakes. The ‘e’ means they have a built in cutoff cable that I can plug into my BBSHD or hub motor.
  2. 203mm Tektro Type 16 rotors front AND rear. These are downhill rotors that are 2.2mm thick. Magura brakes are meant to work with 2.0mm thick rotors (typical quality rotors are 1.8mm thick). The Magura calipers will work with the Tektros albeit only barely with fresh pads. Often when I set up a new bike, I swap in partially worn pads from one of my other bikes and give that other bike new pads. By the time the new bike wears thru these swapped-in partially worn pads, the rotors have enough wear that they can take new Magura pads no problem.
  3. Magura MT7 4-piece pads. I still use the 2-piece MT5 pads that come with the brakeset, but as soon as they wear out, I switch to the MT7 pads, which fit perfectly. They have the performance advantage of delivering significantly more measured torque according to reviews. They also can be taken out with your fingertips without removing the caliper from its mount. MT5 pads on the other hand come out from the bottom and to do that you have to dismount the caliper. So better performance and easier maintenance.

The Big Battery

Fopr most of the life of this bike I have been using a 52v, 17.5ah battery pack I bought in 2017 from Luna Cycle. This pack has a 50a continuous BMS and uses 25R cells. The pack has been in use on three successive bikes over the years and has seen almost daily use, with two charge cycles per day since I charge at the office and at home. However, thanks to my ridiculously rigid adherence to best practices when it comes to battery charging, that pack has almost miraculously lost no measurable amount of its original capacity.

However, a bike this size eats power. Especially the way I ride. Recently I purchased a 21ah pack from this vendor and have been very pleased with it. It only barely fits in the Size Medium frame triangle, but it does fit.


The End?

For the Surly? Hell no its the One Bike To Rule Them All. Really, its a great bike and I intend to ride the wheels off of it.

Is it the end of the mods to this bike? Pretty much I think, with the exception of the summer wheels I’m making up using the MYOBDs and a pair of Apache Fattyslick fat tires, for that Kojak street commuter look. Since its a true slick, we’re talking summer wheels for sure. But maybe not as I live in California and like the old song says, it never rains here.

Kickstand Kaos

A whole page on a kickstand? For a bicycle? If you are riding a 100 lb freight train whose weight can quadruple when loaded up, there’s more to ponder over than you might expect.

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos (you are here)
Episode 4: Add a Flight Deck. And a Hangar.
Episode 5: Leftovers
Episode 6: Electrification

The Surly Big Fat Dummy is a fantastic bike, with one widely acknowledged weakness: The kickstand.

There are those out there – possibly this includes the staff at Surly – who say this is a feature and not a bug. The BFD after all was created as a bikepacking, overland trailblazer. You don’t need no steenking kickstand since you can just lean the bike up against a cliff face, or an axe handle.

Begrudgingly it seems, the Big Fat Dummy is delivered with a kickstand that on any normal bike would be pretty sturdy. Alas on this monstrosity, it is adequate only when the bike is empty, and woefully inadequate when loaded.

How do I know this? Well, ask around any user group, but insofar as personal experience goes: On my first shopping trip with my new freight train, I went to Costco and loaded up four packs of soft drink cans. Since this was Costco, each of those four packs holds 36 cans. Thanks to a total lack of planning and intelligence on my part, I created a load where just the soft drink cans weighed over 100 lbs.

Memo to Me: When shopping on a bicycle, pay attention to how heavy the cart is before you leave the checkout line.

So, my wideloaders were sturdy enough to handle this. My great big panniers were more than big enough. But… how am I planning on loading the bike, then loading the (14 lb, 2-meter) chain and u-lock, and only then climbing on the bike and rumbling across and out of the parking lot? During this loading process, I learned first-hand how important a solid stand was. The next 15 minutes after this picture was taken were a big adventure.

Figure 1: All quiet at the bike rack… things are about to go horribly wrong.

Moving Forward

So, the problem is obvious: If you are using the BFD as a cargo bike and not a bikepacking bike, the kickstand is way out of its league. Has to be replaced. Period. Talking to folks on the various Surly user groups, the Rolling Jackass with its roughly $400 price tag is the best commercially-available solution.

Its DIY Time

I wasn’t ready to fork out that kind of money. I was bound and determined to build my own stand, and I had an idea. How tough could it be?

If you have seen my article on the wideloaders for the Surly Big Fat Dummy, you may have noticed (and seen mention of it in the post) there were some oddball fittings pictured that served no purpose in the published design. That is because I planned an integrated kickstand as part of that project.

The idea went thru a number of iterations. I started with the idea of using simple ‘pegs’: a 3-way elbow on the outside edge, with a length of tubing extending to the ground and terminating in a rubber crutch pad. Place it maybe in the front, or perhaps the rear. Perhaps one on each side, or maybe the front and rear of just one side… what about front on one side and rear on the other?

After mulling the possibilities, I came to the conclusion that every type of peg idea was fatally flawed. There was just too much potential for the bike to fall over while attaching the pegs, or removing them. Especially loaded.

I ended up settling on this: use a 4-way elbow joint on the inner, forward tube joints. Form the actual stand from two pegs attached to one another by another tube to make a ‘U’. And furthermore, make the ‘U’ stand up on its own with another 4-way tee sprouting two short arms that become stabilizing props. This will let the stand be placed in position without someone holding it while the bike is set up onto it.

Its a whole lot easier just to show a picture of the final product than it is to describe in words:

Figure 2: Crossbar with standy-up crossbrace thing completed

By the way, I used the same marine rail fittings that I used for the rest of the wideloaders, so these connections, with a little Vibra-Tite, are guardrail-solid.

The whole idea of making it self-standing was a happy accident sprouting from my need to turn two leftover short pieces of pipe into a full-length crossbar. the 4-way tee was a leftover itself, that I thought I was temporarily pressing into service. I didn’t think to add tubing and feet to the two unused, open holes until I glanced over at more leftover parts lying on the floor. Adding this self-standing (and load distribution) feature turned out to be crucial once I actually tried to use the stand.

Figure 3: This picture was actually taken before Figure 2, during initial construction/guesswork.

And this is what ended up working. I measured the vertical tubes so they only raised the bike up by a bit off the ground. This was crucial as attachment was achieved by lifting the front of the bike up and simply plunking it down on the stand. This is the part where inadvertently making the stand able to sit upright turned out to be (very) useful.

Attaching the stand is easier to do than it sounds. Load on the bike is on the back wheel. Lifting the front is not very difficult even when the back is loaded. And keeping the rise low on the stand is important because it means you don’t have to lift up the front too high.

Removal is also simple. Lift the bike up and the stand falls away (sizing is crucial for this to happen so the stand doesn’t hang up inside the fittings). Push the bike back an inch and set it back down. Grab the stand and toss it into your panniers.

It Works! more or less…

Success! And I still had $400 in my pocket, but… really… after using it for about a month every day, I found the attach/detach process was kind of a pain. As an exercise in problem solving… as a fun project… it was great. But as an expected convenience used with a daily driver. No bueno. And if you have wondered to yourself if, while lifting that bike onto, or off of, the stand it might just fall sideways… I had a few close calls but it never happened, even with a full grocery load.

Still, if your use of the bike is more occasional, this could be a viable option to add into your wideloader project.

Or skip the wideloaders, do a short front crossbar only, use simple single elbows for the stand pegs and work out how to flip it up and down… You could make just a stand with a little more effort and some smarts.

Figure 4: Kickstand/workstand in use

I ended up relegating the kickstand to a portable work stand, and bought the Rolling Jackass (they can both fit). In Figure 4 above I am at a city park, with the bike up on the ‘work stand’ so I can clean and lube the chain. The work stand does a better job than the Rolling Jackass because the latter can come undone if you mistakenly push the bike forward. Not possible with the fixed stand. I like doing basic maintenance at a park after a ride so the time and effort to make this stand was not time wasted.

A short Afterword on the stand…

I made one more improvement – sort of – that might be more successful for someone more determined than I was to see it through. There was a second issue beyond just lifting up the bike and putting it down onto the stand. That lift was actually fairly easy. The real potential for annoyance was if the stand shifted a hair, or my aim was off by a smidge, and the bike hangs up and sits atop one of the open tubes of the stand, rather than sliding into the fitting. Solution to that was to walk over and give it a little kick which, 9 times out of 10, would work. Sometimes not if my aim was really bad, though, and I would have to retry the process. Like I said: an annoyance.

The boat rail fitting itself has an internal chamfer to make fitment easier. And there is quite a bit of extra material there to allow you to hog it out further to make a much bigger well. That would work great. But these are steel fittings about 3mm thick. My poor little Dremel’s grinding wheels just polished that steel and little else. Something bigger and badder was needed and I wasn’t up to it at the time (the job needs a drill and a big internal chamfer bit).

Instead, I rounded off the ends cheap and easy with 7/8″ round end caps. this worked perfectly, but the caps are so tall they make the stand a bit wobbly, since so much less of the pipe is now in the socket.

Pop this onto the tube end. Problem solved.

Whats Next?

So, we went round and round with the kickstand and in the end, bought one and use the other for a work stand. Fine. I’m not done yet as there is one more goofball problem to solve.

Where I work, I am lucky to have my own private garage where I can park the bike, hook up a charger, turn on a couple of industrial fans to blow the sweat off me and change into proper work clothes. I’ve even got a small air compressor, a big rug and a nice padded chair.

There’s only one problem… to get into that garage I have to make a U turn through a narrow walkway under some stairs.

Figure 5: uh oh…

It was never an issue until I built a bike almost three feet wide and over 8 feet long. Yeah I sort of didn’t really focus on that until after I had the build completed. You’ve probably heard the story about That Guy who bought a pickup and then realized he couldn’t fit it in his garage? What an idiot, right?

Problem Solved!

Use the little dollys that people use to move around pianos and pool tables.

Figure 6: Choose your product carefully. A lot of them have horrible reviews.

Throw one under each leg of the kick stand and just wheel the thing around as you please. Easy peasy.

Figure 7: Hello Dolly! Note the Rolling Jackass, and the still-in-place elbows for the ‘work’ stand.

Moving the bike into the office garage through that narrow entryway is a snap. Without them its still possible but involves a lot of dragging and lifting and fighting and cussing.

Last But Not Least (At Last!)

Take a close look at Figure 7. At the feet of the Rolling Jackass kickstand. Underneath them. Looks like some kind of disc or foot? Well, it is. If you refer back to the Frankenstein boots for the Ursus Jumbo, I did essentially the same thing here. The idea was the steel feet of the Rolling Jackass – are thick steel. they will probably last a long time, but I want them to last forever. I also park the bike in places where I do not want the floor scratched (like the marble floor of my bank’s lobby. Yes really).

Using the same process I described in my other post on the Jumbo, I layered on about 10-12mm of Shoe Goo… the artificial shoe-leather. It became a flexible but durable sole to the Jackass’ steel shoes. Before applying the Goo, I roughed up the smooth steel surface of the feet with some power tools.

10-12mm may seem thick, but that thickness is necessary to keep the edges of the steel feet from digging into the ground as you lever the stand into the down position.

The security guard at your bank will thank you for taking the time to go that extra mile.

Add a Flight Deck. And a Hangar.

The Surly Big Fat Dummy has a great big deck in the back. Using a 40″ kicktail longboard and some hardware, Lets make it bigger. And a double decker to boot.

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar (You Are Here)
Episode 5: Leftovers
Episode 6: Electrification

In the Beginning…

Back when I put together the Mongoose Envoy Project, I used a skateboard deck to cover over the long, but only marginally-useful-on-its-own rear framework to create what ended up being an aircraft carrier landing deck.

I started out with a 33″x10″ double kicktail which I mounted on top of eight 25mm tall by 13mm dia. spacer posts. The idea behind the spacers was to give me some working room to attach a net to the top of the deck, and have room to easily mount its hooks to those posts. It worked well, but I left money on the table with only a 33″ deck. I could go longer. So I did. I found a 40″ longboard with a single kick and mounted it on 10 posts, this time.

It was great, but of course, I thought I could go one better. So I scored a 44″ double-kick longboard, and – since the 25mm posts were a bit fiddly trying to get my fingers in that small space – swapped out for taller 40mm replacements. I also made some other improvements, and that deck remains on that bike as you see it here to this day.

Fast Forward To The Present…

Now I have a Surly Big Fat Dummy, and I want to do the deck idea one better (AGAIN!). I still have the 40″ deck left over from the Mongoose build. Since the BFD is already like 8 feet long I don’t need something that makes it longer, so this ‘shorter’ deck will do just fine. I drilled some new holes, repainted it and took the spacers a step further.

The Next Level (literally)

Unlike the Mongoose, which had nothing but a framework, the Surly Big Fat Dummy already has a pretty good deck as it is. On the Mongoose Envoy I was trying to cover over the bare framework and make something useful. This time I am trying to make something already useful more so.

To preserve the utility of the existing deck, I went with much larger spacers. That created a ‘hangar’ under the deck of this aircraft carrier of a bike. This new hangar’s purpose is to house things that need to be carried along, but generally kept out of sight. Stuff where I can benefit from it being reasonably handy, but kept out of the way.

Great Idea. But first I had to assemble the parts and make the thing.

To give plenty of room between decks, I went to McMaster-Carr and acquired ten 3″ long alloy spacers, 5/8″ outside diameter, sized for 1/4″ bolts. Then I went to Pegasus Auto Racing and, after measuring the exact stack height I would need, grabbed ten AN4 1/4″ hardened airframe bolts of the proper length, along with ten AN970 hardened large-area washers for 1/4″ bolts (for the top deck side) and a bag of AN960 1/4″ x 0.32″ flat washers, where I would need 30 for the deck underside, plus the top and bottom sides of the alloy dummy deck. I wrapped up the party with ten AN365 nylock hex nuts.

Airframe bolts have a specific thread length designed to fit a single bolt and a single double-thick washer. This project uses 4 washers of two different varying thicknesses. Measure carefully.

Wow thats a lot of hardware

Like my previous decks, I wanted to use enough spacers and bolt anchor points to make the deck an integral, structural part of the frame. No wiggling possible. Part of what it takes to do that is to use the widest spacers I can find (the 5/8″ OD are it, and dictated why I couldn’t stay metric). To further solidify the connection laterally, I needed washers everywhere clamping everything.

You can still see the holes from when the deck was bolted to the Mongoose, as well as the holes for the trucks that aren’t there anymore.

And excepting the spacers themselves, its all Grade 8 hardened steel. Its. Not. Moving.

Notice also I used hex bolts and did not bother to work with countersunk heads, matching washers etc. as with the previous decks. This thing is spray painted in truck bedliner to help keep things from sliding around, and the hex bolt edges do the same job.

Airframe bolts exist in a wide variety of very finely diced sizes. I am not giving the size I used because the ones you may need will vary according to the thickness of your top deck.

Here’s what the finished assembly looks like up close:

Now that the aircraft carrier has a landing deck, we find out what we stuff down underneath in the hanger.

Up front, fitting just barely between the front posts, is a 3-amp weatherproof adjustable charger that is a permanent companion to this ebike. In the middle is the toolkit for this bike, containing a pump and all sorts of other goodies. It fits just between the two sets of spacers so it can be dragged out the side. And in the back we see a big thick plastic ziploc freezer bag wedged in between the rear 4 stanchions. Thats the in-case-of-disaster emergency inner tube.

Since then I have added another little jewel:

Thats right. A folding chair. Held rattle free thanks to the net. Stuck in line at curbside pickup? Have a seat and relax.

Take the crap off the top of the deck and you have yourself a work table. Or a coffee table. Or a picnic table. Its 40″ long so use your imagination.

See that net? Its 30″ long before it gets stretched out, and since I ordinarily have the Great Big Bags on the bike, I generally do not need to use the top deck for storage of items up so high. But when I do, that nice long cargo net does a great job.

Here is one of the rare times the bags are full and I need to stack something up on the deck other than a rolled up jacket

Now What?

Got a Big Fat Dummy? And a drill? And a skateboard? Make yourself one of these. Next time you have to sign a peace treaty, host a banquet or make off with an emergency supply of toilet paper… you got this!

Quick Release, Easy-Carry Ebike Battery Setup

Parking your ebike outdoors all alone? When shopping, my cargo bikes are locked but out on the street… but the battery goes in with me. Here’s how I do it without people thinking I am carrying a bomb.

Yes You Can Take ‘it’ With You

An ebike used for utility purposes is, by its nature, going to be left out a lot. You go to the store, load up a shopping cart, come back and fill up your saddlebags. You really want all the parts on the bike when you left to still be there. Especially after loading on 50 lbs of cat food, Oreos and diapers.

The most obvious way you keep the bike itself is to use a good locking strategy. I’ll save that for a different discussion. This time I will focus on how I protect the single most-expensive component on any ebike – the battery. Not by locking it up, but by making it so I can do a quick grab and carry it in with me.

By removing that battery, we are making that big heavy ebike into a boat anchor, which we can hope makes it at least a little less attractive to thieves.

Size (and Shape) Matters

What I am describing can be made to work with any shape battery, kept anywhere on your bike. What you see here works best with a squarish, oblong battery. In the pics below I am using a 17.5ah Luna Storm battery, which is pretty big and heavy (in part thanks to its powerful but not-so-energy-dense 25R cells). More likely, if you have a similar heat-shrink battery pack like this one, its quite a bit smaller and lighter.

I also keep a Luna Wolf Pack battery like this and do not use its magnetic mount. The battery is easy to quickly get off that mount, but leaving it inside of a bag like I describe here is, overall, easier than stuffing it in every time, taking it back out and so on. For packs like this (Wolf, Shark, Dolphin etc.) you could certainly bring a small pack and put it in/take it out as a part of your routine.

There’s more than one way to skin this cat, so what you see here is just a jumping off point.

Lets Get to It

This is the battery in its bag, just like it would be if I rolled up to the local Costco.

Ignore the charger cable in the front. I took this pic at work in my ebike garage.

If we zip open the bag, we don’t see a battery. We see an inner bag, along with that charger cable extending thru to the rear. The controller cable is in there too just out of sight (look closely and you can see it)

If we look inside the bag, we see the battery charge cable is in fact an extension running from the rear of the interior bag up and out the front. The motor cable – an XT90S connector – also has a short extension between the battery cable and the motor cable. The idea is this: when routinely, frequently detaching and reattaching the cable, if there is any wear its on a cheap, replaceable extension and not a critical, live/hot cable coming directly off the battery.

Disconnect the cables and give a tug to the inner bag. Here its shown halfway out but you will just pull the thing out in one motion.

When I leave, I generally put the cables back inside and zip it only halfway-ish, so its obvious there’s nothing worthwhile to steal inside. Move along.

Annnd here we are. the cables are shown sticking out of the inner bag. You will want to cap those for safety’s sake. I use cheap plugs I got a bagful of on Fleabay for a couple bucks.

And yes… as-is I have had someone ask me “what is that a bomb?” … only half joking and ready to clock me if I make a sudden move. So stuff the wires in the bag so they don’t stick out.

Tell the Bomb Squad to cut the red wire

Done! Wires are capped and stuffed into the bag in 5 seconds. The sling strap goes over your shoulder for easy carry. I just lug it to the nearest shopping cart and put it in the bottom rack with my helmet and off I go.

This is just a 3L hydration bladder pouch, the sling strap that comes with it and a shoulder pad I swiped off another strap I wasn’t using.

Parts

Its a really short list with one item on it.

Hydration Carrier

You see above the Blackhawk S.T.R.I.K.E. carrier in use. Purchase link is here. Yes, the name is a tad ridiculous. But this pack is minimalist and is just durable cloth with no insulation or padding. Its easier to stuff into a confined space. Mine came with a super sturdy velcro sling strap.

Another that is well made (and a tad smaller for a tighter fit is sold by Voodoo Tactical. It comes with thin backpack-style shoulder straps that don’t take up *too* much space in your triangle bag and are not enormously fiddly when stuffing back in there.

Another one I use (with my Luna Wolf pack) is this government-issue USMC carrier. The link is to a brand new unit. I got mine surplus and cheaper on Fleabay. This pouch has no straps (you can clip on your own from a duffel bag if you like) and it is the opposite of the Blackhawk carrier: Its thick and padded. I can still stuff it into any triangle bag I have despite this. Its great as a protective layer over a battery.

Wrapping It Up

There are lots of ways to do this. How I do it is no big deal. Key takeaway here is to find a method that works for you so you can swiftly grab the battery, go off to your next adventure and then come back and plug right back in again.

Surly Big Fat Dummy Wideloaders

“Wideloaders” are a load-supporting framework that sit level to the rear axle on a cargo bike. They are not made for the Surly Big Fat Dummy, but the frame has fittings to attach them. Here is how I made mine with no special tools or fabrication skills.

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders (You Are Here)
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar
Episode 5: Leftovers
Episode 6: Electrification

Do It Yourself (its not like you have a choice)

Wideloaders go hand in hand with the use of XL panniers like Great Big Bags 2.0. If you have Wideloaders that your bags sit on, it lets the frame support part of the load directly and increases carry capacity. So, for my Surly Big Fat Dummy, I definitely wanted these.

Big Fat Problem

The Big Fat Dummy is a unique frame design. It is similar to the Surly Big Dummy. There’s a family resemblance to XtraCycle-compatible frames. There are many factory-original and aftermarket options for those bikes, but similar is not ‘identical’ or even ‘compatible’. BFD owners figure this out pretty quick.

The image below shows a bright green Surly Big Dummy frame overlaid onto a Big Fat Dummy frame. The front wideloader mounting points are lined up (look for the frame hole/white circle on the bottom tube extension, aft of the bottom bracket). This overlay makes it clear the rear mount holes don’t match. You need Wideloaders designed specifically for the Big Fat Dummy frame.

Image credit: Surly Bikes (click image for original page)

Unfortunately that product doesn’t exist. If you want them, you make them. So I did.

Lets Get Started

Your wideloaders are going to mount in the front and rear hollow tubes that already exist in the frame. These cross-tubes are both 7/8″ Inside Diameter (ID), so you will need to buy 7/8″ Outside Diameter (OD) tubing. Luckily, this is widely available. However you will find a variety of thicknesses, heat treatments and alloys. I’ll pass along what I think is the best to use, and, well, what I used. I’ll let you decide whether or not to follow my lead or make some changes, as what I did turned out to be really REALLY heavy duty, but also heavy for what it is.

What about copper tubes?
You can go a different way and use copper tubing and soldered joints for a very, very cool look. But its no lighter than the alloy and screw-together approach I used, requires semi-permanent solder connections and a whole lot more effort (and money) to put together. It will look incredible when its done though. If you go this route yourself, note that copper tubing is designed to have a specific liquid flow rate, so it is measured via its Inside Diameter rather than Outside. So while I am using 7/8″ tubing, your typical copper tubing that fits is going to be known as 3/4″ tubing. The deciding factor to proper fit will be wall thickness so pay attention when doing your buying.

Parts List

27.49  6063-T5 7/8" OD x 7/16" ID (0.219" wall) x 8 ft
43.00  AL7005 22.2mm OD x 1.8mm wall x 1000mm len (qty 4)
43.96  Stainless boat hand rail 90-degree elbow (qty 4)
43.92  Stainless boat hand rail Tee (qty 4)
12.88  Stainless Mil Spec 0.89" ID Washer 10 pak
11.98  2:1 1" heat shrink - 25 ft
14.98  Reinforced 7/8" ID garbage disposal hose
       (10 ft) (qty 2 optional)
 3.00  Stainless steel M6 socket caps
       flat washers
       nylock nuts (2 ea)
29.74  2" x 30" hook/loop cinch straps 6 pak (qty 2)
31.90  Ratcheting tube cutter (optional)
29.99  Inner/Outer Pipe Reamer (optional)
10.99  12" Flat Bastard cut file (optional)
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In original build but replaceable with disposal hose
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12.74  Corrosion resistant sleeve bearing (2)
 6.24  Abrasion-resistant cushioning washer 10 pak

Total project cost (not counting shipping): About $230.00. $304 with the optional tools added in.

Notes on the Parts List

Tools

  • Your life will be a lot easier with the tube cutter and ratcheting attachment. It makes doing the job of making repeated cuts easy and gives a perfect cut every time.
  • Once you are done cutting a tube, even if done with the tube cutter it will still have sharp and somewhat bulged edges. Use the reamer to give a finished bevel to the outer and inner edges. You could use a straight file, or a tiny long round file, and eyeball it until done. But this specialized tool does a quick, clean job in just a couple seconds.
  • You need a few passes with a flat file on the flat of your cut pipe to smooth out the surface after the cut. Well actually you don’t need it, but between this Flat Bastard and the reamer you will never cut yourself on a sharp edge. And yes I picked this file to link in because they called it a Flat Bastard (any bastard cut will do, or even a fine cut).
  • If you choose the 6063-T5 tubing you likely also will need a hacksaw. I am not linking one or giving a price. If you don’t already have a hacksaw in your toolbox you may as well pull your toga up over your head and accept your fate.

6063-T5 Tubing

This is an extreme-duty choice. With a wall thickness of just under 1/4″, it is heavy stuff. But use two of these as thru-frame cross-pieces and your wideloaders will not bend even with well over 100 lbs of cargo loaded on them. My record is about 160 lbs (72.5 kg) and I was glad I over-did it, especially when hitting road bumps… an overloaded bike that weighs over 500 lbs with the rider onboard is a runaway freight train: you have to just hang on and bulldoze thru things you would otherwise avoid on the ride home.

This tubing is too thick for the tube cutter. You can use the cutter to get it started, then switch to a standard-issue hacksaw, or find some other method of cutting this very thick tubing. Me, I went cutter+hacksaw. It worked fine, but was something of a pain in the ass.

AL7005 Tubing

This stuff is sold in metric measurements since it is coming from a bicycle frame tube supplier, but the measurements translate to 7/8″ OD tubing with walls about 0.071″ thick, in individual lengths of 39″. That is roughly the thickness of bicycle handlebars. As aluminum tubing goes, its thicker than most reasonably-priced alternatives, which is good. Its also much lighter than the 6063 I used for the crossbars. You can sub in two tubes of this 7005 for crossbars less insanely thick than the 6063. They will still be strong.

The pipe cutter makes life a whole lot easier.

Stainless Boat Rail Fittings

Being thick stainless steel, these marine boat fittings are all about durability and strength. Also they are heavy as hell for bicycle components. Once again, this is a job where weight weenies need not apply. You put these suckers on and screw down their grub screws into the softer alloy tubing and they will hold fast, regardless of whether or not you forget how wide the bike is and walk it into the corner of a wall … in that contest, the wall loses.

hmmm… This piece is not on the parts list

Worth Noting: In many of the pics here, you will see I am using tee and quad-fittings that allow more connections than are necessary for the project in this post. Thats because I was building with an additional integrated center-mount kickstand in mind. We’ll save that for a separate article. Stick to the parts in the parts list to just build the wideloaders.

Garbage Disposal Hose

What in the hell is that doing on this list? Fact is, I didn’t build my wideloaders originally with this in mind. You will see many pics here with the older bushings, washers and heatshrink tubing for coating. I got the idea a few months afterwards. Covering the outer tubes in thick tubing permanently dingproofs them and helps protect whatever I lean the bike up against.

Once I found cheap PVC garbage disposal hose, I realized I could further use it to replace almost all of the washers and spacers in the build.

Originally I used 3 layers of cheap heatshrink to cover the tubes, plus bushings and washers. The garbage disposal tubing replaces all of it and saves about $30 on project cost.

Since I had already built mine, I personally only used the disposal hose on the outer facing tubes, leaving the two inner lengthwise tubes covered in heatshrink. However, you could buy two units of the disposal hose and sheathe all of your tubing with it. Simpler, looks kinda neat and about the same cost.

25 feet of Heat Shrink

The need for this stuff was largely eliminated with the use of the garbage disposal hose. However, you still need about 2 feet of it (20″, actually) to line the crossbars inside the frame. In a cruel lesson in Chinese capitalism, 10 feet of 2:1 heat shrink is one cent more expensive than 25 feet. So what the hell lets get some extra. Also, the 3:1 that is widely available in shorter lengths is the marine grade with adhesive glue inside and thats too thick for our crossbar liners. So… maybe its not a bad idea to check your local hardware store before buying this stuff. Its not going to be any cheaper but if you don’t want an extra 23 feet of 1″ heat shrink tubing sitting in a drawer for the next decade, a local buy might fix that.

The Sleeve Bearings and Washers

I used these in my original build and you can see them in all the pics. They were optional then and, later on when I discovered the garbage disposal tubing, were replaceable in the project. The one remnant I would still use regardless are the “mil spec” steel washers. Why mil spec? They are cut to closer tolerances than ordinary washers. If you want a really snug fit to your tubing, with a not-gigantic OD to go along with it, these washers are pretty much the best option.

If you use the disposal hose to replace the cushioning washers and bushings for spacing, I would still use the mil spec washers up against the frame to ensure the most solid contact possible.

Set the fastening screws facing UP on your tee fittings. If they come loose you stand a chance of seeing the problem before they become UFOs.

Construction / Assembly

NOTE: While I often go into painful levels of detail, I won’t be specifying measurements on cut dimensions. I don’t want you taking my word for what works on your bike and your fittings. I’ll make one exception to this: The width of the crossbars, since that requires some thought and is worth discussion. We’ll get into that below.

Step 1: Cut the Crossbars to Desired Width

This is maybe your most important project decision. How wide do you go? Your answer will help determine what you bump into while trying to move the bike around, or smash into as you try and negotiate a narrow passageway (like a shared use path entrance). At a glance, a good rule of thumb for maximum width would seem to be ‘no wider than your handlebars’. That will mean whatever you are riding thru, if your handlebars fit then most likely the wideloaders will not snag, either.

While you are figuring this width out, know the center section of the Surly Big Fat Dummy is exactly 10″ wide.

The BFD 26″ bike in Bliolet uses Answer ProTaper bars; 810mm wide. That works out to almost 32″ of width, give or take. So knock 10″ off of 32″ (the width of the center section) and divide by two. Following the no-wider-than-handlebars thinking, you would have wideloaders 11″ wide on each side. The 1-piece crossbar would be a total of 32″ in width.

Thats way too wide. Forget about the handlebar rule. It sounds like a good thing to have that nice big shelf, but it will be VERY ungainly to have that much hanging off the side. Don’t even think about it. Another issue is trying to get the bike thru a door. Think how much fun it will be to get a bike 32″ wide (and almost 8 feet long) thru a doorway that is commonly no more than 36″ wide. And some doors are 32″ wide.

I settled on a bar that is 26″ in length. Subtracting the 10″ center section and dividing the remainder means I have an 8″ crossbar extension. The elbow will extend my width a bit more. So figure in the end, I have about a 28″ wide rear platform. Here again the dictating factor is getting thru a doorway (I park in a garage every day and bring the bike in thru a door at a sharp angle).

If you are unsure, its better to guess on the too-wide side. It is a whole lot easier to file or cut metal off than it is to put it back on again (fun fact: this is also the First Rule of Gunsmithing).

Step 2: Drill And Fit the Crossbars

This part is easy. I took the 26″ cut crossbar and measured it to 13″. Then I used a red Sharpie to mark the center. In the pic below, a test-fit, you can see the red mark coming thru the centered frame hole. Once you have confirmed the spot is in the right place (measure!), pull the tube out and drill a centered hole straight thru at the spot of that marker dot. Drill large enough for an M6 bolt.

Finalize Crossbar Fitment

Once you have drilled that hole you can fit the tubing right inside the 7/8″ ID frame tubing and attach the crossbar, centered exactly to the frame and fixed in place with a stainless M6 socket cap bolt, nylock nut and a washer on each side. However, there will be a small amount of play between the crossbar and the frame, which means these things will rattle. We can’t have that.

  1. Add a length of heatshrink – cut to a 10″ length to the center section of the crossbar. Using your heat gun, shrink the tubing so it sits tight on the very center of the crossbar. The hole you drilled will be a clearly visible depression on the bar.
  2. Get a bit of dishwashing liquid or similar non-permanent lubricant and smear it over the now-snug heatshrink.
  3. Push the crossbar into the frame. It will now be very snug thanks to the added diameter of the heatshrink. The dishwashing liquid will let you push the bar into the hole while leaving the heatshrink attached and placed on the center. You may have to experiment with lesser lengths of heatshrink as it might want to be pushed back by the frame as you get further into the frame and closer to centering it (I had to spiral wrap sandpaper on a wooden dowel and run it thru a few times to debur the interior of the frame. If you already own a cylinder hone of the right size this is a place you might carefully use it).
  4. As you push thru, when you see the depression in the center frame hole where heatshrink sags in under your drilled bolt hole, stop. Now just shove the washer’d bolt into that hole. It will break the heatshrink on its own. Clamp in with the nut on the other side.
  5. Repeat the process with the other bar.

Your crossbars are now tightly, permanently fit. Bolted into the frame and lined with a thin rubbery material, they will not rattle.

Step 3: Fit the Tee’s and Inner Lengthwise Bars

Now that the crossbars are bolted in, its time to attach the inner bars. What you see in the pic below is a test fit where I hadn’t yet finished Step 1 above. The crossbars aren’t yet bolted in. But the procedure is well-illustrated. Loosen the grub screw on your front tee. Stuff the bar into it until it stops. Measure how far it went in. Position the bar atop the rear tee. Its going to go in the same distance, so measure accordingly. Thats your tube length. Cut to size and if it fits, do one more like it for the other tube on the other side.

To do the actual fitting once the tube is cut, loosen the grub screws in the tees so they are still in place, but do not intrude at all into their opening (or remove them completely and stash in a safe place). Place the cut tube into each of the tees. Make sure the grub screw holes are facing up for both tees. Now slide this assembly over the attached crossbars and slide them inward to their final position. If they do not slide smoothly to the interior – if they hang up halfway down the crossbar for instance – you may have cut your tube a bit too long and need to make a second cut, or do some filing if its a near thing.

This is a good time to mention that for placement on the drive side, you want the inner bar to clear the derailleur when it is on the smallest cog, with some extra room to spare that allows for frame flex (although these wideloaders can’t help but stiffen the frame). Keep this in mind when you are deciding final placement on the drive side inner bar.

When the tees and tube are sitting, unbolted, in place, move on to the next step.

Position the inner tube on the drive side so it doesn’t hit the derailleur in high gear.

Step 4: Fit the Elbows and Outer Lengthwise Bars.

Repeat the process from Step 3 for the outer bars. This time measure fitment with the 90-degree elbows. In the pic below note I had a tee in place in the rear – I was considering doing an extension out behind. In the end I thought an 8-foot-long bicycle was plenty and squared it up with an elbow.

After cutting the tubes, do the same procedure as in the previous step with regard to placing the bar and elbows onto the frame without permanently attaching anything.

When the tubes are all cut, everything is lined up and you know it all fits, its time for Step 5.

Step 5: Add The Bumpers / Final Assembly

Since you didn’t actually tighten anything down in Steps 3 and 4 above, its easy to take it all back apart. Do so now, leaving only the crossbars, which should already be firmly assembled. Your next moves, in order:

Straighten out Your lengthwise (long) pieces of Disposal Hose

OK this is out of order because you should do this a day or two in advance of your actual build party. You want to give the hose some time to uncurl itself.

Off the shelf the hose is kind of a pain in the ass to deal with, considering between two and four lengths of it need to be cut fairly precisely to a bit under a 3-foot length. I found two ways to deal with this (and used both of them). First, the easiest way:

If you have some long lengths of 1 1/2″ hard PVC pipe laying around, stuff this curved tubing inside of it. Let it sit like this. You can do it with 1 1/4″ PVC but its a tight fit and really tough to get it thru in lengths any longer than about 3 feet.

If you don’t have PVC, use your actual wideloader tubing. If you are following the parts list above you have four individual tubes that are longer than you will need. Work with those. This is going to be a snug fit and require some elbow grease to stuff it on there. I stuffed on a couple of feet, then dripped on some WD40 and let it penetrate (there’s a bit of slack to let it dribble in) and just worked it. Once I had used enough of it (used… not over-used), and let it spread, they slid on and off easily. But it takes a little time and patience. Afterwards, wipe off the tubes. I didn’t worry about the residual WD40 inside the hose itself. Just enough remained to make final assembly straightforward.

I let this sit overnight and added a length of PVC on the still curly side to help straighten the rest of it

Cut spacers for frame-to-inner-tee fitting

You will cut spacers to desired lengths from the disposal hose. On each corner, use one of the milspec washers up against the frame for a total of 4 washers needed. The milspec sizing will give the washer a nice even fit.

On the build you see pictured, I used 1.5″ corrosion resistant bushings in the rear for a nice look and exactly the spacing from the frame I wanted. In the front, I stacked three of the rubber cushioning washers, sandwiched by two milspec washers. This front scheme was a leftover from earlier plans that did not include bolting in the front crossbar. Thats what you get when you plan a build and buy parts before you get the bike in hand to work with directly. You will want to just cut a short length of hose and back it with a washer.

Line the inner lengthwise bars

You are going to do one of three things here:

  1. Line the inner bar with 2 or 3 layers of heatshrink. Do multiple layers in case you scuff or ding the bar. Just one layer is easily torn. This was my initial build because its all I had figured out how to do at the time.
  2. Line the inner bar with a length of garbage disposal hose. to match all the other bars. Using the disposal hose is cosmetic on the inner bar, but it is more durable and will give you a consistent, beefy look. Doing this is almost the same cost as using the comparatively fragile heatshrink. If starting over from scratch, I would go this route.
  3. Do nothing and leave the bar bare. If you like the bare look then great you are done.

Install the inner lengthwise bars

At this point you are ready to do the final install of the inner lengthwise bars. Having attached any desired covering to the bar, loosely reattach the tees to the bar and slide it on just as in Step 3, again making sure the grub screws for the tee fitting are facing up. When in place up against the spacers you cut and installed above, its time to tighten the screws.

This is one of the few times a thread locker is properly in order vs. being a misused crutch. I personally prefer Vibra Tite. The blue gel is easy to apply, never hardens and holds tight regardless of vibration and impacts over time. Goop up the threads of each grub screw and tighten them into the softer alloy tubing until they are roughly flush-fit to the fitting. Nothing is going anywhere once that is done.

Line the remainder of the crossbar

Now you need to line the next section of crossbar if you care to do so. At this point I will say that heatshrink should not be an option – go with the flexible PVC (or do nothing if thats your bag). Cut each length to size and slide onto the tube.

Line the outer bars (or don’t)

Almost the same procedure as the inners: Affix your elbows to the tube and attach the tube assembly to the crossbars. Now you know how much exposed crossbar there is. measure this and cut your outer bar liner/bumper. Tighten ONE of the elbows onto the outer bar and remove the elbow from the crossbars. Now you are holding the outer bar with one elbow attached. Take your cut liner and slide it down until it is snug against the installed elbow. If you cut the liner to the proper length, it is now installed perfectly centered.

Since I did my bumpers after the initial build, I lined the outer bars first – the crossbars are bare in this pic.

Install the outer bars

Loosely attach the second elbow to the outer bar. Slide the assembly over the crossbars. Tighten all the grub screws down so there are no gaps, using thread locker and again tightening so the grub screws are roughly flush with the outer wall of the fitting.

We’re almost done .

Step 6: Add the Floor (Straps)

Up to this point we’ve created an empty framework. It needs a floor to help hold up the Great Big Bags that will be sitting on top of it. I opted to use 2″ x 30″ hook-and-loop cinch straps, 4 on each side, which are movable, super lightweight, have some give to them but at the same time are very strong.

I had to buy two 6-packs of straps to get what I want, so I could add more straps, but 4 is enough and more importantly I can space the straps in such a way they work in complement to the four pannier straps I use to provide additional support on heavy loads.

Since the bag straps also have to wrap around the inner bars of the wideloaders, the floor straps have to be out of the way, and what you see is spaced out to let me interleave the bag straps between the floor straps.

A Final Note on the Floor

At around $30, the floor straps added a noticeable bump up in job cost. Is there a cheaper way to do this? Probably. I considered a bunch of ideas including diagonally weaving super thick bungee cord into a floor. I have a spool of the stuff in my garage.

What about more tees and crossbars with the leftover tubing bits? Without question that would look great and be supremely sturdy… but is it necessary? I don’t think so, and I didn’t feel like taking the time, adding the weight or going to the expense. But for sure, it would look great. In the end I felt the straps got me to the finish line immediately and were easiest to manage over time.

What about skateboards?

Well, that would work great. If you are a parent and your wideloaders need to serve as platforms for little feet, and maybe you want your kids to be able to stand on them, then a skateboard is a great option. If you use the really thick 6063-T5 tubing it will for sure be well-suited to a couple of M5 holes drilled thru each bar to attach that board, front and rear. From there, find a blank deck to your liking and bolt that sucker on.

The floor straps are spaced so I can interleave two more bag straps between the two center floor straps for extra support with heavy loads.

Job Done. They Work Great!

These pics are from the initial build, and reflect the parts I used for spacers at that time, along with some showing a different strap setup. Your results may vary so the bags you buy or build may dictate a still different approach.

Great Big Bags 2.0 – 138L (each) Panniers… Seriously?!

My first set of Big Bags were 77L each, almost the same size as the largest generally available cargo bike pannier (and 1/3 the price). It turns out you can go a lot bigger than that and stay practical.

The Surly BFD Project Menu
Prologue
Episode 1: 138L (each) Panniers… Seriously?! (you are here)
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar
Episode 5: Leftovers
Episode 6: Electrification

When I put together my first set of Big and Cheap DIY Cargo Bike Bags, I thought two 77L panniers were huge! I fit them onto my Mongoose Envoy cargo bike project, and for several months they have been great, but not quite perfect. Not because of the capacity of the things. They were perfectly sized for that mid tail frame. But there were a few convenience issues … you’ll see below what my solutions were.

Why go bigger?

Well, I liked the Mongoose mid tail so much (it was my first dedicated cargo bike) I decided to jump all in and go for a full sized longtail with as much capacity as I could get my hands on. The Surly Big Fat Dummy was a bike I had *almost* bought before the Mongoose, and I decided with its fat tires, sheer size and very stiff frame it would offer the larger carry capacity and greater versatility I was after.

Going from a mid tail to a long tail meant I had more room for bigger bags. I could do the Rothco 77L canvas bags again, but after quite a bit of shopping around, I found Rothco’s larger, heavy-canvas 34″ long, square zipper’d duffel bag was dimensionally just about perfect to fit the BFD’s rear cargo area.

But, I am getting ahead of myself.

Parts List

$92.00 Rothco Jumbo Canvas Cargo Bag (qty 2)
  7.08 C.S. Osborne #5 5/8" hole Brass Grommets (qty 10)
 44.00 Cross Linked Polyethylene - 2lb, yellow 72"x48
 15.00 7/8" thick hardwood dowel (qty 2)
 20.00 12" soft cargo loops, 6 pak (qty 2)
  7.21 7/8" rubber chair feet 4 pak
 36.00 74" buckled 2" wide luggage strap 2 pak (qty 4)

Total Project Cost: About $221.00.
Result: 276L of pannier space. Two Hundred and Seventy Six Liters.

Notes on the Parts List

Foam
I am sure you can find something cheaper. I wanted something bright yellow so I could see the contents of the bag easily. Cross linked polyethylene is essentially a thin version of gym mat material. Extremely fine-celled. I have used Foam Factory for some esoteric jobs in business for custom cut stuff and found they had what I was after. What you want here is a big single sheet of foam that wraps entirely around the bag interior. The large foam sheet specified here is just over double what you need. Cut it in half, shave a few inches off one side and its a perfect fit. As an alternative you might try a couple of the Therma Rest mattresses that I used in my original bags, and some gorilla tape.

Grommets
You can also use #6 grommets just like I did with the original Big And Cheap Bags. It all depends on what tools you have in your garage. If you have no grommeting tools whatsoever, this #5 size midget grommet kit will give you everything you need – the tool and plenty of grommets. Cost is about $56 and you will have plenty of grommets left over so you can hammer reinforced holes into more things.

The Wooden Dowels
You can go to Home Depot and pay about half what you will at Amazon. Thats what I did, and HD has a handy manual-cut station you can use to cut the rod down if you don’t have a saw (please buy a saw instead). I only put Amazon as a source so there is an online purchase choice.

The Luggage Straps, Part 1
I specified four 2-paks for a total of 8 straps. 4 per side. Generally you only need two. But when carrying really heavy items, like the pictured load below (still in the shopping cart) that weighed about 128 lbs (58 kilos) … you want more straps to help take the burden off of your wideloaders. So, you can buy fewer straps. Or you can buy the max that will fit and toss the spares into your cavernous panniers and forget about them until they are needed. Your choice.

My first shopping trip with these bags was a Costco run. I didn’t realize I had almost 130 lbs in the cart. The duffel in the bottom goes onto the deck and was at least another 20 (Just the lock is 15 lbs).

The Luggage Straps, Part 2
Notice in the pic above, and in my previous Big Bag posts, I used 2″ and then 3″ wide velcro straps (a single 3″ above). these hold fine, but in daily use, velcro is… velcro. It is constantly sticking to things it decides to stick to, and generally making my life more difficult. The straps do indeed do their job, but first and foremost just finding 3″ wide straps long enough to work with these bags is very difficult (and a process I will not describe since I abandoned them). Also these 3″ extra-long unicorns are just too damned expensive. Kydex buckled straps unbuckle in an instant, don’t stick to themselves or anything else, fit 4 to a side which is plenty and cost less to boot. Lastly, the luggage straps I am specifying adjust from 40″ to 74″ which is perfect for folding the bags up, empty, and expanding them out when full. Since the excess strap length is captured via a sewn-on sleeve, nothing is ever flopping around.

Whats With The Dowels?

My original Big Bags used hooks, and I went to a fair amount of trouble to make sure they were absolutely planted and rattle-free. And they are all that. But still, I thought there has to be a better way, and I ended up coming up with one.

Using dowels and cargo loops for hanging the bag has major benefits over hooks:

  • It doesn’t rattle
  • It is light weight (lighter still if you use an alloy tube)
  • It is cheap (less so if you go alloy)
  • It distributes the load on the bags evenly across their entire length
  • It holds them fully secure
  • There are no points of excessive wear/rubbing.

And last but not least, they make bag removal and reattachment a snap. The process described in a nutshell:

STEP 1: Loop-tie five cargo loops per side to the Dummy rails, and loop those up thru the deck itself so they drape down. If you are not making bags for a Surly or Xtracycle-compatible cargo bike, use as many loops per side as you can, as well-spaced as you can make them.

Here is one of my early fitments when I was figuring this all out.

STEP 2: Create 5 grommet holes in the top inside edge of each bag. One on each top corner, and the remaining three positioned so they are roughly equally spaced down the side of your rack. the exact positions will vary depending on your rack. I illustrated the whole grommet-creation process in the original bag creation post. But worth noting for these bags I used smaller #5 grommets and I really prefer this smaller size.

STEP 3: Line up your now-holey bag with the dangly loops and, one at a time, put each loop into each corresponding bag hole. As you do this, thread your dowel thru the loop on the inside of the bag.

Here is what this looks like with no bag in the middle


Annnnnd with the bag:

STEP 4: Remember the rubber chair feet? Put one on each end of the wooden dowel. This keeps the bag from rubbing on a relatively sharp edge of cut wood. Sooner or later it will rub enough to wear thru the canvas. But not if you have a big soft round rubber bumper on that edge.

Note the above pics show a 1.25″ wooden dowel. I downsized to 7/8″ and its much easier to fit the loops thru when putting the bag back on. You can see the smaller version in the pics below. Original concern was the dowel bending, but there are so many cargo loops to suspend it… thats not going to happen.

Spend a few minutes with some fine-grit sandpaper to make the imperfect surface of your dowel silky smooth.

Bag Removal and Re-Attachment

Here it is in a few easy steps. I photographed my first bag removal as you see, and I timed the second with a stopwatch. It took 30 seconds to detach the bag and another 15 seconds to toss the straps in and zip the bag up.

You can forget about making something that fast and easy with hooks.

STEP 1: Unbuckle the two bag straps. Pull the top inside corners of the bag back so each end of the wooden dowel is visible.

STEP 2: Pull off the rubber foot from one side. I removed the rear one this time.
STEP 3: Pull the dowel out from the other side. Its only halfway out in the picture. It will slide out quickly and easily.

STEP 4: DONE. The bag is now free. It is now a big duffel bag with handles you can lug into the house with all its contents. Feel free to use the shoulder strap that came with it.

Did I Mention The Kangaroo Pouch?

Yes really. Just like the original bags, Big Bags 2.0 are typically folded up when empty. The foam liner inside means the folds are fairly thick and a pouch is created in the fold. For bags this big, its pretty deep, too. And almost three feet long. Check out how I almost disappear a 2 lb sledgehammer into it, standing on its end, below.

That makes for secure storage of most daily-use items. On a typical day, a small backpack with my work clothes, pouch with my keys and alarm remote and garage door opener, and another with my wallet and phone are all snuggled in one side or the other. Road bounces and vibrations don’t disturb them, and there is enough room left over that I don’t have to open the bags up at all unless I am on a shopping trip. So as big as these things are, if anything they handle small jobs just as well as the the large ones they were designed for.

I used to think the 77L bags were crazy big. I spent a lot of time agonizing over whether I was wasting time and money even attempting to go bigger with these duffel bags. Now, having had some time to live with them and on more than one occasion to stuff them full, I can’t imagine why I would want to go smaller.

The Surly Big Fat Dummy Project

Prologue (you are here)
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar
Episode 5: Leftovers
Episode 6: Electrification

Less than a year ago, I started the Mongoose Envoy Project. I loved the bike and – after dabbling with fast-carry-stuff ebikes for a few years (that ended up looking more like zombie-apocalypse bikes), it was my first actual purpose-built cargo bike.

The Mongoose Envoy, in its final form with the 44″ skateboard deck, indestructo wheels and big poofy tires

With respect to the cargo platform, I. Freaking. Loved. It. I am not a recreational rider. I never have been since I started riding in the 1970’s. I put in long commute rides, and I try and do as much as I can of my daily errands on a bike vs. uh… one of my automobiles. Yes I have to admit that while I am doing the whole save-the-planet schtick and trying not to drive, its because I love riding bikes and I always have.

I bought this station wagon factory-stock so I could haul my bikes without an external bike rack. That focus shifted… things got out of hand

Anyway, where was I? Right. Cargo bikes. So… I built the Mongoose out until it was truly as perfect as it can be for its intended purpose. Its even a good value and componentwise I would put it up with just about any high end cargo bike. With that said, it has some problems.

  1. It doesn’t fit me quite right. Mostly in the upper body. I have done pretty much what I can to deal with this. A LOT of the problem has absolutely nothing to do with the bicycle and has everything to do with lingering injuries from when I was T-boned by an inattentive driver in a SMIDSY type collision. I did a passable Superman impression on the arc upwards… and a decent impression of Vinko Bokataj for the landing.
  2. It hurts to ride the damn thing. Again, this is all about residual pain from the above-referenced accident and has nothing to do with the bike. My wrists remain in bad shape, probably permanently, and while the Jones bars help by putting my hands at a better angle, I need both a higher upright riding position to take weight off my wrists, and a suspension fork to reduce the impacts that are part of normal street riding.
  3. As the cargo bike platform expanded my idea of what a bike could accomplish, I wanted more than the Envoy, with its mid-tail size and only plus-sized (after upgrading) tires could deliver. Go big or go home as the saying goes, and the Big Fat Dummy is arguably, physically the largest production 2-wheel bike on the planet.
  4. The addition of the larger 2.8″ plus sized tires on the Envoy worked so well, and I have done so much work with the fat tire platform, I wanted to go fat on a cargo bike and take advantage of the added capacity the fat tires give (and since my very first serious Costco run weighed in at a total of over 500 lbs counting me and the bike… good decision!)

So, this section of the blog, of which this page is only a teaser that will eventually house the episode menu, will document the custom work I have done on this bike. What is worth mentioning that is. This is not going to be a rivet-scraping pass over the bike. We’ll just hit the high points.

One bike to rule them all? So far yeah. Its all that.

The BBSHD: Musical Chainrings

It seems inevitable.  When I build a bike, I go through front chainrings trying to get the gearing just to my liking.  My Mongoose Envoy build has pretty much set the world record for tweaks in this regard.  But gearing wasn’t the problem so much as chain alignment.  Alignment is one of the most talked about issues with mid drives and up to this point I have not had to work too hard to get it right.  This build, not so much but I think I finally got it (like $350 later).

While dealing with this I have fooled around with three different sets of crankarms (160’s, 170’s and 175’s).  Not the subject here so if you notice the different crankarms in the pics, I am ignoring them on purpose.

Sidebar:  When building the Surly Big Fat Dummy, I found exactly the same thing as I did here insofar as chain alignment is concerned.  And used the same solution – the USAMade adapter listed as an Honorable Mention below got pulled out of the parts pile and put to use.

The Right Tool For The Job

The Mongoose build is a first for me in many ways.  One thing in particular:  the BBSHD fits the frame really well.  Its a 68mm bottom bracket with absolutely zero chainstay obstruction for the secondary housing.  So I can butt the motor right up against the bottom bracket.  Further, its a lonnnng way back there so chain alignment and misalignment – an inevitable concern with an HD build – is a lot more forgiving since the angles are gentler thanks to the longer reach.  On this bike, if I want I can even forego the offset non-drive side crankarm and the pedals are still easily centered under me.  So the HD is a great fit here.

About That Job…

The Mongoose is a cargo bike.  So it hauls heavy stuff (usually groceries).  It has a secondary job as an unladen backup commuter, but primarily it needs to be optimized to start from a stop while the entire system – with me – weighs 400-450 lbs (180-204kg).  I have really loaded it that heavily so this is not a theoretical exercise.  So I want a big-ish chainring for when I am pedaling fast and light, and still need to be able to get to the big cogs in the back for when I am loaded up and chugging along like a two-wheeled freight train.

Plan A:  Luna Eclipse (42T)

The Luna Eclipse is one of the best BBSHD chainring setups on the market, with a unique ‘wicked’ tooth profile meant to eliminate the possibility of a chain drop under extreme use.  It also has the most extreme internal offset of any chainring option.  This will do the most to overcome the grief visited upon the BBSHD builder by that drive’s secondary housing sending the chainring way out to right field.

Its also gorgeous.  The gunmetal finish I chose matched beautifully with the dark grey frame.  Unfortunately 42T (which is the standard for full-offset chainrings as any smaller and you can’t clear the secondary housing) was not large enough to keep me from clown-pedaling when riding the bike as a commuter.  There was another problem:  Chain alignment.  Running that smaller 42T ring with the smallest rear cog resulted in, after only a few weeks, a whole lot of wear on the inside.  This is why mid drive builds demand the most out of the builder in terms of thinking things thru.  Time for Plan B.

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Its not ruined yet, but its lifespan sure has been shortened.  this was only a couple hundred miles of wear.

The Eclipse is a proprietary chainring platform, but fortunately other sizes are available.  the largest of which is what I tried next.

Plan B:  Luna Eclipse (48T)

So Plan B was to swap in a Luna 48T ring onto the Eclipse center section to fix the clown pedaling, and to stay the hell off the 12T small rear cog to deal with the alignment issue (I am using a welded together steel cluster for durability and the 12T is alloy and not a part of the welded cluster, so its better to stay off it for the sake of longevity anyway).  I thought that 48T/14T on this bike was the perfect sweet spot.  A small front ring is best when its on cargo duty, and a large one is best when its a commuter.  48T, when used in conjunction with upshifts, gave me pretty much everything I needed.

Pretty much but not everything.  First of all, remember the deep offset of the Luna ring?  It moves the chain inboard 24.8mm which *usually* eliminates the damage the BBSHD does to chain alignment.  Not on the Mongoose, whose narrow bottom bracket effectively papers over all of the sins committed by the motor (at this time I had not yet fully figured this out).  So, as I found with the 42T ring, it was inset too far, even when I stayed off the smallest cog.

So Plan B helped, but it didn’t solve the problem.  After only a couple weeks (I am now checking carefully and frequently) I saw the beginnings of the same wear on the inside of the chainring.  Like the 42T, I had to retire this thing fast so I could use it on some future project.

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Not as bad as the 42T, but still bad.  Both this one and the 42T looked perfect on the other side.

Sidebar: A mid drive chain powered by a 1500w motor is a chain saw when it comes to components rubbing against it.  That is just a reality of a mid drive and you have to deal with it as part of your design/build process.  When you get it right, you are golden for thousands of happy miles.  Get it wrong and you are sawing thru chainrings and cogs like nobody’s business.

Plan C: Lekkie Bling Ring (46T)

So now what?  42T was too small.  48T was more or less just right.  And the chainring offset that lets me use the inner cogs at great alignment still needs to be reduced or I can’t use anything but the lower gears.  Lekkie has a Bling Ring available in 46T.  It has the same internal offset their 42T ring has and, since I use them on two other bikes I know they are top quality.  At 18.3 mm its offset is quite a bit less than the Luna.  So I got a 46T.  I also added a 2mm spacer underneath it, further reducing the chainring offset to 16.3mm.  That is a whopping 8.5mm less than before so I hoped I would be good on the smaller outer cogs and still let me use the big inners.

And, pretty much, it was.  Chain alignment didn’t seem to be much of an issue, although it still wore down a bit more on the inside.   I was also able to shift up to the biggest cogs in the rear for very low gearing options.  Those are important on a full cargo load and if I am dealing with hills.

But… I flat out missed that 48T high gear for commuting.  And I was still seeing – very slight but noticeable – wear on  the inside of the chainring teeth from the chain, which was still visibly angling outboard a fair distance.

IMG_20200503_123847
This one was on for a few months and had 8.5mm less offset.  But it still shows signs of premature aging.  This was undesirable but livable.

I decided to try an extreme option I had not previously considered.  But on this bike, where all of the normal chainring offset stuff doesn’t seem necessary, it might actually work.

Plan D: Luna 130 BCD Adapter and Wolf Tooth 48T Ring

BBSHD chainrings are generally all proprietary to the platform.  Not so in the cycling world, where chainrings are universal, needing only to match the proper Bolt Circle Diameter for the chainring bolts.  Match the BCD between crankset and chainring and you are good to go.  There are adapters out there in the world that allow a Bafang motor to use standard 104mm and 130mm BCD chainrings.  The problem is they don’t give you anywhere near as much inward offset.  But given my experience so far, maybe I can live with that.  They should fix my alignment on my ‘commuter’ cogs, but will I still be able to use my ‘cargo’ cogs?

In addition to the LunaCycle 130 BCD adapter, I also chose the Wolf Tooth Drop Stop chainring as those rings are best-in-show for this sort of thing on a mid drive.  Attachment to the adapter was a little different than the usual chainring-to-crank operation in that its backwards.  The chainring bolts onto the inside.  I was able to play some games to good effect:  I reversed the chainring so it is logo-side-inward.  Not as pretty, but doing that lets me take advantage of the countersunk bolt holes on what is normally the outboard side.  The countersinking let me mount a bolt so it is almost flush with the ring, which in turn is butted up almost on top of the secondary motor housing.  With the countersinking it now has plenty of clearance.

Plan D Results

FINALLY.  Everything is working right.  The reduced chainring offset means my 14T cog (still not using the 12T for the reliability issues mentioned above) lines up straight back.  This outboard shift did affect my inner cog alignments but I can still get to all of them but the biggest 32T.  I’m comfortable with the angles on all but the second-largest 30T for long term use, and in a pinch, that 30T will work fine.  I just don’t want to stay on it for a week.  So this 9-speed is now a 7-speed and as DIY mid drives go thats still better than a lot of builds can manage.

And worth mentioning, like a lot of what they do, the CNC-machined Luna adapter is freaking gorgeous, and very precisely manufactured.  So much so it really stands head and shoulders above another adapter I got my hands on and was able to compare it directly to.

Honorable Mention: USAMade 130 BCD Adapter

I was surprised at how well this worked and how nicely it was made.  The part only cost me $29.99 on Amazon.  Still, it was Made in USA, well machined and rock solid.  The only things I didn’t like about it was the fact it was machined a bit too heavily, which meant it placed the chainring a millimeter or two further outboard than was necessary, and in this game millimeters count.  Further, as you can see above I was able to reverse the WolfTooth ring and take advantage of the bolt head countersinks.  That didn’t work with this part as USAMade countersunk the outside edge of their part, which made the bolts too long to allow my trying the same trick on the inside, where I needed it.  For a different build it might work fine so I am keeping it for my parts pile.

As for the Stone chainring seen on the USAMade adapter (scroll up to the title image at the top of the page), thats a Chinese Special that ran less than the godawfully expensive Wolf Tooth.  Its noticeably lighter in construction than the WT and I’m not sure I am sold on the tooth profile.  This ring will sit in my parts pile waiting in the wings as an emergency replacement.