m@Robertson

Big And Cheap: DIY Cargo Bike Bags

There is another post that shows later improvements to these bags. Here is another one that covers a hole I left in this article below.
Great Big Bags 2.0 uses a better attachment method.

I have a Mongoose Envoy that I turned into a project bike. I essentially took a very inexpensive bike with low end components (but a fantastic frame, with a good fork and wheels) and rebuilt it into a high power, heavy duty cargo bike with better components than I’d get if I paid for one from a major manufacturer.

The Envoy comes with two almost-38L-each panniers (24″ long x 16″ tall x 6″ deep). Thats one hell of a lot for a bag on a normal bike. But on a mid tail cargo bike frame, they’re smaller than what they could be.

The stock bags look skinny, and are no thicker than a normal pannier. But I’ve had them loaded with a complete Costco grocery run where the bike ended up well past its 140-lb rated cargo capacity. Using an elastic bungee net to make sure everything stayed tight to the bike, all I had to do was lumber home without killing myself.

Figure 1. A light shopping run – not using front bags. The bags we’ll make here are about the same size as the ones shown, but more than double the width. Note the cargo net used here as insurance that those bags stay put.

So… the bags work great and are essentially free. But I’d like something that better suits the capacity that the mid-tail cargo frame can handle.

I managed to score a brand new set of Surly Dummy bags for a great price. I found they were great bikepacking bags not suited to bulk grocery hauling. Whats needed is a giant hole you can dump stuff into and zip closed.

It looked to me like the Yuba Go-Getter bag ($300 plus shipping for the pair) was the closest fit to this idea, and to my frame (It is meant to fit their popular Yuba Mundo cargo mid tail) I contacted Yuba about the exact size of the bags, and that they would be going on a non-Yuba bike. They promptly got back to me with this:

Length – 29″ / 74 cm
Depth – 10″ / 25cm
Height – 17″ / 43cm
Volume comes to about 84 quarts or 79.5 liters.
It is important to note that we designed the Go-Getter to be specifically compatible with our Yuba Mundos and we cannot guarantee its compatibility with non-Yuba bikes.

Figure 2: A single Yuba Go-Getter bag mounted on a Yuba Mundo cargo bike.

Thats pretty awesome in terms of capacity. However, those dimensions are just enough to worry me on my bike. The Envoy’s bags are 24″ long. 29″ might end up pushing into my heel clearance. The height of 17″ is for sure an issue. Envoy bags are 16″ tall, and its already a problem that those bags essentially sit directly on the lower rack. While the bike frame is rated for 90 lbs, the lower rack is only rated for 20 per side, or 40 lbs total. Now, they can handle much more than that in real life, and I have reinforced the lower rack’s attachment to the frame (Supplementing the factory’s four connections with an additional six that are each stronger than the simple factory bolt), but still a bag that basically sits its weight on that lower rack is not ideal.

What would be better would be a bag that is a little shorter, that bows downward under load, putting strain primarily on its hanging hooks, so only partial weight is borne by the lower rack. Add in a couple straps to help take the load off those 4 hooks and its better still.

I think my solution accomplishes that. Bear in mind everything I did here was done specific to this bike. You can take these ideas and make adjustments so this basic concept fits to yours.

The Budget

Lets call the number I am trying to beat the cost of the Yuba Go-Getter bags, which were my benchmark for capacity: $300. So I wanted this project to come in as far under this number as possible and still get a quality bag. As you can see from the build sheet below, I came in well under the commercial product’s price point.

Build Sheet ($111.50, or $55.75 each)

Rothco Parachute Bag (2)             Amazon   45.98
3"x30"velcro cinch straps (8)        Amazon   21.54
C.S. Osborne #6 13/16" grommets (8)  Amazon   11.36
Stainless 0.3"/0.78" S hooks (8)     Amazon    2.67 
Therm-a-Rest Classic Foam Pad        Amazon   29.95

The Bags

I want something more durable than the fabled, dirt cheap Ikea bag. But really those bags got dropped as candidates because the zippered version is so short at 11″ that it would be putting the load unnecessarily high. Also its 28″ length is again just enough to worry me. And how sturdy is it? The zipper in particular?

I had a candidate already in my hands in the form of a Rothco Parachute Bag. These are simple, cheap $23 bags made of reasonably thick canvas and strong, smooth zippers with a snapped storm flap. Dimensions are 24″ long (identical to the Mongoose stock size), 15″ tall (1″ shorter than stock, so addresses my height/weight concerns) and 13″ deep. Work out those measurements to cubic inches (4680) and convert to liters and you have a 76.7L pannier bag.

Since I already had one of these bags in my closet, I was able to toss in some full size pillows (it ate 3 of them and still wasn’t quite full) and sized it to the bike. Looked like a perfect fit. So I bought two more for testing.

Attachment

After a fair bit of fussing around, trying to figure out exactly how I wanted to attach the bags to the bike (it actually took a few weeks), I settled on primary support being grommet holes in the bags, which will connect to simple S hooks mounted to the frame. These will be further supported by straps.

I used the C.S. Osborne #6 grommet, which has a 13/16″ hole. Why this brand and size? Well, there are drapery grommets, shower curtain grommets and outdoor tarp grommets. The grommets for curtains are nowhere near strong enough to work on a tarp… or a pannier. I knew from experience the Osborne grommets are solid and will distribute the forces involved as well as possible.

I chose a 13/16″ size because… I had the grommets and the grommet tool already.

Sidebar: The #6 grommet size is the smallest size commonly available that will let you fit an XT90 connector thru the hole. Thats why I have the grommets and tools in my garage – from building battery bags for my custom ebikes. I grommet the pass-thru holes in the bags. And since I have been using them for years, I know they hold up. The bag on the right was made in early 2017 and is still in use today. This $12 Amazon bag with reinforced holes is way cheaper than a custom ebike bag.

You can see in the first pic below, three of the four grommets’ upper edges match the seam of the bag, while the forward-most grommet is lower. Oops. My second bag had them all even and all in the lower orientation. Despite the different mounting, you can’t tell the difference in how they sit on the bike.
The single brass grommet was deliberate as I wanted a quick visual cue to help me orient the bag. Brass = rear for both bags.

Straps

Not wanting to rely totally on the hooks, there are two dedicated three-inch velcro cinch straps. These are actually made up of two 30-inch straps combined to make one longer strap. I had to do this as there does not appear to be a 3″ wide velcro cinch strap in a 60″+ size on the market. If you wanted to save some money and use a narrower strap, 2″ cinch straps are widely available. In fact, the pics below show an early test fitment where I was using 2″ x 72″ straps, which worked OK but were so long they were a bit unwieldy. Shorter straps were more convenient and the wider 3″ version provided more support.

The right way to use the straps: Loop over the rack at top, and the very bottom, directly underneath. But do NOT loop under the lower rack and then go up over the bag. Instead, from the bottom of the bike frame, loop the strap directly under the bag and then back up to the top. The top loop over the rack helps support the bag’s weight. The bottom loop onto the lower portion of the frame (or rack depending on your bike) helps hold the bag close to the frame so it won’t flop around. And the remainder of the strap, directly up against the bag and not under the lower rack, holds up the bottom of the bag, preventing – along with the padding – the bag from sagging.

Bottom loop over the frame. On the drive side you will want to be careful to ensure you are not contacting the chain.

Notice… the strap goes over the rack, not under it.

A lot of the weight of the bag is transferred to these straps.

3″ straps ended up being used in the final build to provide more support.

An early fitting using 2″ straps and testing use of a top strap to keep the two weight bearing straps together (turns out its not needed). Bag is stuffed with a king sized 0-degree canvas double sleeping bag… and its still not truly full.

Hooks

These are pretty straightforward. I wanted an S hook with beveled edges that allows quick attach/detach, but at the same time is shaped in such a way that the bag will not easily come undone from it as I bounce from pothole to pothole. I searched for months for such a hook for a cargo net and fell into the ones I am specifying in the build sheet. Originally meant for my cargo net, they are also perfect for this project as well. I have the painted black versions but I am spec’ing the unpainted stainless versions. For your own personal bike, you may need something different. Follow the link above and note the seller offers three sizes.

More Options

Most of the reason I used pre-made cinch straps rather than buying webbing and fastex-style buckles is that hook/loop strapping is much easier to adjust. This makes it easy to cinch up the straps when the bags are empty, and fold the bags up quite nicely. There is even a deep, wide pocket formed by this process that is a decent candidate for stuffing in whatever fits.
During testing of the bag when fully loaded, I ran a 15″ x 30″ cargo net from my top rack, over the bag and underneath to the bottom rack. It provided great support to keep the bag from sagging, and held it firmly, close to the frame. For really heavy loads this looks like a smart thing to have available; especially since it can lay flat in the bottom of the bag and take up no extra space.
I have a 24″ x 36″ cargo net (see it in action in Figure 1 above) that I can use to stretch over my entire cargo area. Up over a side bag, the loaded upper deck and back down over the other side. For big, heavy loads, a net like this can put a gentle, compressing and enveloping grip over the entire load in the rear.

Where Do You Go From Here?

Unless you have a Mongoose Envoy then your bags will need to be tailored to whatever your bike fittings are. Expect to put the grommets in different places. Maybe use a different size of S hook. Don’t expect my project to work perfectly for your bike although the parts I am using should be mighty close to universal once you space things out per your bike’s needs.

In the photo above: I had so much room in the new bags after loading up my shopping cart, I never even used the 36″ x 12″ duffel that sits atop my 40″ rear deck. There is almost 154 liters of pannier space in those bags, and after dumping that whole shopping cart into them (the front bags helped too)… they still aren’t full!

Mongoose Envoy – Chapter 8 (Low Cost Builds)

Introduction: The Mongoose Envoy Project

Chapter 1: The Raised Rear Deck

Chapter 2: Better Brakes

Chapter 3: What Kind of Motor?

Chapter 4: Motor Choice

Chapter 5: Motor Installation

Chapter 6: Misc Upgrades and Notes

Chapter 7: The Build Sheet

Chapter 8: Low Cost Builds (You Are Here)

So in Chapter 8, I put up a Build Sheet. If you do all the math, you will find my $750 bike turned into a $3600 bike (some bits, like the battery, I already owned and just plugged in so cashwise I am not out the full parts total). Given how expensive quality cargo bikes are, and the level of quality I have now, I am very happy with that cost vs. benefit. I have a really solid frame and top quality components, and a bike that is probably the best all-around transportation/auto replacement bike I have ever owned.

But what of all of this was actually necessary? I build bikes as projects. Generally, I am more concerned with making the bike the best it can be. I don’t pay as much attention to final cost as most people would. Especially since I oftentimes upgrade in bits and pieces, which is less of a shock to the budget.

Based on my experience with the stock Mongoose bike – seeing first hand what worked, what didn’t and what I changed because I had more money than brains – I can see a different way to go that might be of a lot more interest to people who just want a good bike that doesn’t break the bank. For the record, I’m of the opinion that the Mongoose Envoy represents a significant break from current cargo bike offerings in that it can be built into a first class solution for a lot less, thanks to its bargain basement starting price.

So… lets build a few different configurations using my kitchen-sink, spaghetti-against-the-wall build. In the end, I replaced everything but the frame, headset and fork.

All prices are in US Dollars. The last two builds are non-electrified.

Build #1: Just The Very Basics+Assist ($1,807.48)

This is a low-cost build that changes only the things that I think must be replaced.

Right off the bat, you can see I left on the Magura 4-piston MT5 brakes, and the great big (but relatively inexpensive) thick rotors. These brakes work so smoothly and so well when I have had this bike fully loaded. I think you’d be insane not to take any and all uncertainty completely out of your braking equation. These brakes are not overly powerful when you consider the duty cycle they will have to put up with. Safety first, but this choice also guarantees trouble-free ease of use.

This build uses the BBS02 because it is lower-cost and still does a spot-on job. You can see from my motor choice post that if I did not already have other BBSHD bikes in my stable, I would have chosen the ’02 for this build as it is ideally suited for the cargo bike job. The cost below does upgrade to the mini color display; adding $40. Knowing the different displays as I do, this is well worth that minor upcharge.

Note I changed the shifter… that has to happen thanks to the change in brakes. The stock brake levers are combined with shifters (cheaper that way, I bet) and if one goes, so must the other.

Mongoose Envoy Bike               Amazon               731.49
Magura MT5 disk brake set         bike-discount.de     137.00
ISH-203 203mm rear disk adapter   bike-discount.de       6.86
QM5 203mm front disk adapter      bike-discount.de       6.86
Tektro 203-17 downhill rotors (2) ebay (hi-powercyles)  42.40
MicroSHIFT TS70-9 shifter         Amazon                22.88
BBSO2 motor kit                   Luna Cycle           490.00
   68-73mm standard motor
   mounting hardware
   wiring harness
   speed sensor
   basic crankarms
   Luna 500C mini color display
   Universal thumb throttle
Battery Solution
   52v 12.5ah battery pack, basic Bicycle Motorworks   369.99
   pack construction, 50a BMS and
   Samsung 25R cells

Build #2: Change Out The Drivetrain ($1,933.00)

Includes everything above, plus the following, which adds $144.61 to the build price.

Everything From Build #1 plus...
KMC X9.93 chain (7 feet/more links)  Luna Cycle   57.75
Shimano HG400-9 12-36T cluster       Amazon       25.99
Shimano RD-M591 9spd derailleur      Amazon       41.78

This takes out the frankly bottom-end Shimano drivetrain and in its place substitutes a smooth-as-glass 9-speed click-shift setup. Yes the chain is expensive but if you want to do a mid drive right, you have to pay attention to the chain and the rear cluster, which in this case is a durable, steel, welded-together unit that will give longevity and will not tear into your cassette body.

You can get a strong steel cluster with an 11T small rear cog, and I suggest you resist the temptation. 11T cogs are always problematic on mid drives in the first place. On a cargo bike the problem is worse. The speed you can achieve dropping that one tooth is likely unattainable anyway. Especially when you factor in the weight and the motor-bogging that will occur under load. Don’t do it. Get the 12T.

Worth noting: The stock Mongoose 8-speed cluster is also a welded steel unit so its just as survivable. Also the Mongoose chain is an 8-speed KMC, so its likely just as durable. The weak links – no pun intended – are the rear derailleur and shifters. Mine worked poorly although I intended to replace it with a 9-speed from the get-go, so I didn’t try to adjust it into compliance.

At this point, we have a really first class electrified cargo bike that stops easily, shifts smoothly, will survive over the long term thanks to the components we plugged into the drivetrain… and we’re still under 2 grand.

Build #3: Add a Front Rack ($1,988.48)

Yikes we’re still under 2 grand here!

Everything From Build #2 plus...
Front Rack 
   Axiom Streamliner Front Rack  Amazon       46.99 
   Delta AxelRodz skewers        Amazon        8.49

Adding the front rack greatly increases your versatility. For mine, I use waterproof RockBros 27L panniers similar to Ortlieb rolltops: They are big, carry a lot and mount about 2″ low on the rack.

Note my discussion of the installation of this rack in the Odds and Ends post. You’ll need to spring for about 20 stainless 5/32″ fender washers to fit the rear AxelRodz skewer onto your front axle. This sounds crazy but really, it works very well.

Build #4: Beef Up The Drivetrain ($2,187.43)

We’re adding almost $200 with just these next two parts.

At this point, since we are building with a BBS02, we’ll want to address its weak links a little differently than I did with my BBSHD.

The Lekkie chainring gives you some offset to bring your chain line back into alignment, provides a tooth profile that eliminates any chain drops and lasts, essentially, forever provided you do your part as described in the mid-drive section of the motor musings chapter.

Everything From Build #3 plus...
   Lekkie Buzz Bars (crankarms)  California-ebike    99.00
   Lekkie BBS02 46T chainring    California-ebike    99.95

As for the crankarms, those are self-extracting, quality bits of forged alloy, versus the low-end Chinesium alloy used on the stock arms. Those square-taper arms are often replaced, and the fact they only cost about $15 each makes said replacement relatively painless… but never having to replace them in the first place is an idea that has some merit.

You can consider the crankarms an optional option and see if you pedal hard eough to make them fail, which you might not, in which case you’ll save yourself a hundred bucks.

Build #5: No E-Assist, Proper Parts ($1,081.69)

What about just treating the Envoy as a ‘donor’ to make an analog bike? Take advantage of the great frame and replace the iffy components to make yourself something really good for really cheap?

I did not throw on the hand built uber-wheels, or change the tires. Both of those components work well on the stock bike. Sure I think custom wheels and upgraded tires are a good idea, but they are icing on a cake and, particularly with the wheels, spike the build price up considerably.

I focused on turning the bike into a silky-smooth-running, safely-stopping hauler.

The drivetrain – excepting the front crankset – was replaced with a great Shimano 9-speed long cage derailleur
The chain may seem expensive, but you’ll have to buy two 9-speed chains to make one long enough to fit this bike, or just buy the super-strong one I did that is in one piece already with no potential mid-chain weak spots where the two chains would otherwise be attached together.

Mongoose Envoy Bike                Amazon            731.49
Magura MT5 disk brake set          bike-discount.de  137.00
ISH-203 203mm rear disk adapter    bike-discount.de    6.86
QM5 203mm front disk adapter       bike-discount.de    6.86
Tektro 203-17 downhill rotors (2)  ebay               42.40
MicroSHIFT TS70-9 shifter          Amazon             22.88
Shimano HG400-9 12-36T cluster     Amazon             25.99 
Shimano RD-M591 9spd derailleur    Amazon             41.78
Shimano FD-M591 derailleur (front) Amazon             29.95
KMC X9.93 (two of them)            Amazon             36.48

Build #6: No Electrics, Fully Loaded ($1,566.41)

This one has almost everything but the kitchen sink thrown in for max comfort and quality. Here again though, I left off the hand built wheels.

The Thudbuster LT is pricey but its such a big change to the comfort of the bike, a top build has to have it.
$90 for a kickstand is hard to choke down, but if the bike falls over once at the store with 100 lbs of groceries in the bags… it doesn’t seem quite so expensive.
Those Jones bars are just too comfortable. Nothing wrong with the stock bars… but if we are throwing on stuff to feel good, these have to be on the list.
I use the RockBros panniers with my own front Axiom rack and decided to include them here. They are big, waterproof and inexpensive. While you do not want to overload your front rack, these can carry jumbo bags o’ tortilla chips without squishing any. So as usual, size does matter.

Everything from Build #5 plus...
Thudbuster LT 27.2 XL            Amazon      119.99
Ursus Jumbo Superduty kickstand  Amazon       79.99 
Jones H-Bar SG Loop Handlebars   Jones Bikes  79.00 
Jones 205mm Kraton Soft Grips    Jones Bikes  20.00
Front Rack 
   Axiom Streamliner Front Rack  Amazon       46.99   
   Delta AxelRodz skewers        Amazon        8.49
   RockBros 27L Panniers         Amazon      108.99

Wrapping it all up…

The first four builds above address all of the functional weaknesses of the $730 Mongoose Envoy. Do these things and you have

upgraded an analog bike into a solid electric performer
addressed every functional weakness in the original bike

The last two builds take a look at the same thing, but go in the direction of making the bike the best it can be without a motor.

One functional item I am leaving off here is a heavy duty wheel build. While I have one in progress, and its on the build sheet, the fact is I have not yet killed the stock wheels. Nor have I ding’d them. They are still nicely true, and my desire for a 30mm internal, survive-the-apocalypse set of wheels can be argued as me overdoing it… again.

There are a lot of other line items on my personal build sheet that are not discussed on the electric builds. Stuff like the Thudbuster seatpost, or the Jones bars. These address personal comfort issues that don’t need to be there. Those are items you can spring for individually over time… or not. You know how the bike upgrade thing goes…

So have at it!

How I Bleed My (Magura) Ebike Brakes

This is sort of a companion post/supplement to my Mongoose Big Brake post (go there for links to resources on cable cutting and bleeding). Worth putting up separately as its a topic that comes up from time to time in my travels, and putting it here will let me just link it into a discussion.

These directions assume you are working with Magura brakes. However, they should translate reasonably well for a generic application (for best results find specific instructions for your model).

Next time I do it, I’ll take some pics so I can spruce up the page a bit.

Toss a small towel on the ground under the caliper you are bleeding. Just in case Something Bad happens.
Leave the caliper on the bike.
Get everything ready because once this process starts oil is going to be dripping out of and onto things. ‘get ready’ means in part to get your lower syringe with the bleeder hose fully filled in advance, with the hose filled with fluid not air bubbles.
Loosen the lever on the handlebars and re-orient it so the brake reservoir is level to the ground
With the top bleeder still in place, which will limit the rate of fluid loss somewhat, open the bottom bleeder and haul ass to get the syringe screwed onto it. I usually manage to get only a small dribble onto the caliper. Tighten the syringe onto the bleeder with an 8mm wrench and make sure it is on tight (not ‘crank arm’ tight… go just a skootch past ‘snug’).
Remove/open the top bleeder. Since the bottom bleeder on the caliper is closed, nothing is going to be leaking out yet. Attach the top syringe/reservoir.
Do one cycle of bleeding, bottom to top and back to bottom, gently, to establish vacuum and ensure you have a good setup and don’t have any leaks or surprises. While doing this, periodically tap the caliper and fluid reservoir in the lever with something firm like a *small* dead blow hammer (or the handles of your pliers) to help dislodge any stuck bubbles.
With a full bottom syringe, push the fluid up through the system… hard this time. Not enough to break the syringe or do something crazy, but enough so you can see the oil well up in a wave in the top syringe. On the return stroke back down, be gentle so you don’t suck any air in via the edges of the top syringe seal.
Repeat Step 8 until you no longer see tiny occasional streams of bubbles. You can stop when fluid is in the bottom syringe, drained from the top syringe, with just a bit of fluid in the top syringe (say… 2-3mm or so) for the next step.
Using the 8mm wrench, break the lower syringe loose and as soon as you are able, spin the thing off the bleeder by hand. Have the bleeder screw ready to pop back on asap because fluid will start dripping out immediately. Important: The little bit of fluid you left in the top syringe will keep the reservoir topped up unless you screw up and are too slow to get the bleeder bolt back on..
Remove the top syringe and replace the cap screw, taking care not to overtighten … its a plastic bolt and need to ONLY be snug (0.5nM, officially).
Mop up. Chances are good you only got a little on the caliper from Step 9.

Mongoose Envoy – Chapter 6 (Odds & Ends)

Introduction: The Mongoose Envoy Project

Chapter 1: The Raised Rear Deck

Chapter 2: Better Brakes

Chapter 3: What Kind of Motor?

Chapter 4: Motor Choice

Chapter 5: Motor Installation

Chapter 6: Misc Upgrades and Notes (You Are Here)

Chapter 7: The Build Sheet

Chapter 8: Low Cost Builds

This section holds various bits that I changed that do not fit anywhere else or do not merit their own Chapter.

The 76L (each) Panniers

This needed its own writeup and, since it happened after the bike and these chapters were finished, got its own pair of standalone posts. In the months since I first put them together, they have proven perfectly durable and saved me about $200 over commercial bags of about the same size. Big And Cheap: DIY Cargo Bike Bags.

Front Rack

This bike cries out for a front rack. It is after all a cargo bike, and loading it up is part of the game. Sure, weight on the front wheels is not conducive to stability, but if you have ever done a bicycle tour, you’ve learned to deal with the issue. Besides… for a grocery getter, a front rack with a couple of nice big panniers is perfect for bags o’ potato chips, loaves of bread or similar high-volume, low weight delicate items. I do have to admit… one time I loaded the front bags up with soup cans. That made for a hair-raising ride home.

Normally on my fat bikes, I use an Axiom Fatliner rack, which is rated for a whopping 50 kg (110 lbs). For this nonfat bike, the Axiom DLX Streamliner is the next best fit, and it too is rated for 50 kg. Now… you’d be out of your mind to load that much onto it, but its nice to know it can handle a lot more than I will ever put on.

Axiom racks use an oddball kind of armature that threads thru the QR skewer and shifts the rack rearward a bit. In this case, I am going to take a rear rack and stick it on the front… so those mounting arms will shift the rack further forward.

Here’s where it gets weird: A common complaint on this rack is the arms add *just* enough width to make it difficult or impossible for your skewers to fit over the arms. I had exactly the same problem. No way was it going to fit. I tried using Axelrodz skewers whose front skewer was – on paper at least – long enough to work. It wasn’t. So I came up with an alternative that ended up, if anything, working better than if things had fit right (and still used an Axelrodz skewer). Look at the front axle closely in the pics above. It doesn’t look quite right…

I keep a supply of stainless steel 5/32″ fender washers on hand as they are cheap, easy to buy by the box at Ace Hardware in any US town, and a perfect fit for an M5 bolt. More snug than an actual M5 large-area/fender washer, in fact. Since they are large-area, they are just a smidge wider than the skewer’s contact area with the fork. They are also just as wide as the contact area of the rack mounting arm. If I stack a half dozen of them on the axle, the rack – which was meant for a 135mm rear mounting – fits much better, with perfect full-contact with the washers. If I stack another half dozen or so on the outside of the rack arm, then clamp down a REAR 135mm axle rod… Job done. If I remember right, I used 6 washers on the inside, and 6 more on the outside. I set it up so there is absolutely full thread engagement on the rod.

Doing this also eliminates the risk of someone walking up, flipping the QR skewer off and wandering off with my front wheel. An M5 hex key lets me pop off the wheel easy-peasy, almost as quick as a quick release.

Parts List:

Axiom Streamliner DLX rack
Axelrodz QR skewer replacements
5/32″ stainless steel fender washers

Thudbuster LT

I have maybe 3 of the Thudbuster Short Travel posts on other bikes, and one Satori Animaris – a $50 alternative that I found well worth the money with virtually no downside vs. a Thud ST. But for the Mongoose, I decided to go to a Thudbuster Long Travel post. I bought the XL version which is a full 450mm long. Not so much because I need it (on this large frame, a normal 400mm would have worked fine) but so I can potentially use it on a smaller frame if I ever need to swap it out. At about $150 a pop these suspension posts are pricey.

Having many thousands of miles under my … belt … riding short travel suspension posts, this is my first long travel version. I wish I had bought long travel all along (and in fact since I got this one, I retired my Satori Animaris for another Thud LT on my daily driver bike). The trick to getting this to work right is to adjust the pre-travel screw so its already pretty stiff when you give it a shove with your hand or upper body while standing next to it. When putting your full weight on it, it will move quite a bit but you won’t realize it. But your bum will.

I installed a thudglove neoprene cover. Not so much to keep it clean – its a city bike after all – but to make my use of a $150 seatpost a little less obvious. I took a black sharpie to the white lettering on the glove to tone down the advertising volume a bit.

I also used a seat leash. These are not ironclad theft protection, but they will stop anyone from a quick grab, and if you have a bolt-on seatpost clamp like I do, even loosening that will not let someone walk away with the seat. They will have to disassemble the seat from the post itself to be able to walk away with the seat, or the post, or both. Of course, if the thief has a decent set of bolt cutters, or an angle grinder, they’ll make short work of this, but the leash is a great security measure against all but the prepared, dedicated thief.

Parts List:

Thudbuster Long Travel XL (450mm total length) in size 27.2
Thudglove
Seat leash cable for a bit more theft protection

Dual Seatpost Clamp

A seatpost clamp? Really? Picking nits, are we? I’ll explain. This is kind of a big deal, actually.

The Envoy comes with a typical quick-release seatpost clamp. It works, but you figure out real fast you have to absolutely clamp the bejesus out of it to get the post to stay still… Unfortunately it turns out the seat tube of the frame is just a hair over sized. So the seatpost is going to require unusual amounts of force to fix it in place. This is not so great for the frame.

Its even worse when you want to substitute in a quality seatpost; in my case a Thudbuster to soften the ride. The Thud’s ribbed-but-polished-anodized surface is just slick enough that the QR post clamp simply will not work unless I clamp so hard I fear for the frame’s survival. This is after all an alloy frame, and alloy often prefers to break before it bends.

I did manage to get myself a thicker wider-clamping-area carbon fiber clamp on Amazon for about $12. When clamping that to frightening levels (and only then) I found it could hold the Thudbuster steady… although I did not test it for more than a couple of rides. I replaced it with this doodad as soon as it arrived:

You want the exact sizes shown in the image above. 27.2mm for the seatpost and 31.8mm for the seat tube of the frame.

I bought it on EBay for about $25 (You can also find them on AliExpress. Amazon sells the ‘KCNC twin seatpost clamp‘ for about $40). It turns out dual clamps exist because carbon fiber seatposts tend to slip. Why does this design fix the problem? Clamping both post and tube solidifies the connection. Considerably. I have had no shift whatsoever in my post height since installing this piece, and I didn’t have to put undue stress on my not-replaceable frame.

You may have to do a little extra searching to find this specific type of “double seatpost clamp” versus one that simply is thicker and has two bolts. Those frame-only clamps put all the extra stress on the frame which is not my preference.

Ursus Jumbo Kickstand

The stock kickstand is a good product, but when you have loaded up the Envoy after a Costco run, you’re on shaky ground even if you are absolutely level: Bump the bike wrong or let the handlebars with their laden panniers flop around, and the bike can easily tip over. It does after all, weigh probably another 140 pounds or so and thats before you climb on.

I asked around at the Cargo Bike Republic group on Facebook and one of the options was the Ursus Jumbo kickstand. Its an $80 option, but believe it or not its not the most expensive option by a long shot.

You can see the extra wide Ursus stand above. In this picture, the bike is loaded with well over 100 lbs of Costco booty. Note I loaded the bike way too close to the rack. I was unable to roll it forward to raise the stand. Next time: turn the bike completely around before loading.

The stock stand spreads about 7 inches, or just under 18 cm. The Jumbo on the other hand spreads over 40 cm. It also keeps the front wheel only *barely* off the ground. Perhaps a half inch. Thats a good thing as I see it. Raising the kickstand while the bike is loaded is a different approach to the stock stand, where you push the bike forward and gravity + momentum force the stand to retract (with a thunk, and the bike plops down at the same time). With the Jumbo, you physically pick the bike up at the front and retract the stand while its in the air. Different, and more difficult for sure. But the added stability is dramatic. Its worth the extra effort.

Jones Handlebars

With clear/soft Kraton grips.

I’ve taken to Jones H-Bar handlebars on all my bikes after an inattentive driver hit me back in December of 2016. The resulting injuries left me with wrist pain that I can only deal with for short rides. The Envoy has a similar handlebar design, 710mm wide with a less-pronounced 27-degree sweep vs. the Jones 710mm and 45 degrees. Unfortunately I’ve decided the sharper angle of the stock handlebars is too much for me. They are a good effort from Mongoose to provide a well-functional bar out of the gate… but if I want to go on 15+ mile commutes the discomfort is unfortunately spoiling the ride and lasting well into the next day… when its time to go ride again. The Jones bars are a known fix to this problem for me. Highly recommended on general principles.

Parts List:

Jones SG flat bars
Jones clear/soft Kraton grips

Custom Built Wheels

Given the kinds of weights I am dealing with in a cargo application, I wanted an indestructible wheelset. Worth noting: The stock Mongoose wheels never let me down and never took so much as a shimmy; always staying true. Further, the steel cassette body showed zero wear after 300 miles of use with the BBSHD motor in play.

I knew right off the bat I wanted to build the wheels with a DT Swiss 350 Hybrid rear hub. The Hybrid is an insanely sturdy hub designed with ebikes in mind. Compare it to the already mighty 350 Classic and its … well, you’ll never break it. the 350 Classic’s super strong splined engagement system has been upgraded from the already-best-in-class 18T to a 24T for even faster engagement, and the spline wheels are solid rather than the stock units which are now skeletonized.

A DT FR560 is my rim of choice for indestructibility on an enduro bike, and they would have been my choice here, but I’m trying to keep the cost down… and I found the Sun Ringle MTX39, which is tailor made for downhill and freeride nightmare rides, making it also perfect for cargo. It makes for a crazy strong wheel like the FR560, at half the cost (and maybe twice the weight 🙂 ).

SIDEBAR: I went 32H not realizing the 350 Hybrid uniquely comes in the unusual-but-preferable 36H configuration. Since the MTX39 is also available in 36H, and so are Shimano front hubs… I could have done an even stronger wheel build. Frankly given the components in use here (DT Alpine spokes are just as overbuilt as everything else on the parts list) its almost hard to imagine needing that extra bit of strength, but I would have done it if I had realized the rear hub had that option before I ordered my other parts.

Sun Ringle MTX39 Rim 26″ 32H (30mm internal width)
DT Swiss 350 Hybrid ebike/tandem rear hub. Steel cassette body, 24-tooth splined ratchet engagement. 148mm thru axle converted to 141mm QR.
Shimano M475 32H front 6-bolt disc hub
DT Swiss Alpine spokes

Stock Mongoose Envoy rims are on the spec sheet as 26mm internal width, when in actuality that is their external width. Internal width is 20mm which is ok but nothing to write home about.

Likewise I could spend much more on a front hub, but a workhorse basic Shimano hub will do the job just fine.

12ah Portable Battery

Full description pending.
My battery needs to be easily removable as I carry it into the store with me. It also needs to be easily concealed in the store as I don’t need someone seeing thick red wires and thinking I have a bomb in the bottom of my shopping cart. Also, my runs to the store are usually only a few miles from home, so I can get away with a smaller battery, which – double bonus – is easier to lug around.

Tires

I’ll admit it. I’m a tire whore. I’m always looking for something a little better, a little different, and oftentimes I don’t wait for one set to wear out before I jump ship and throw on a different set to see if I have finally found the Grail. Usually, I have a stack of the things sitting in the garage, as a result. Since the Mongoose has 26″ wheels like my old Stumpjumper FSR, which I converted to a street bike powered by a Cyclone mid drive, I already had some tires in the pile to play with.

Naturally, I didn’t use them right off and instead bought more.

Firstly, the stock Chaoyang tires are decent. They are rated 26×2.35 but in a first for Chaoyang, exceed their size spec and measure out to have a casing 2.5″ wide at a comfy 50 psi. Pulling them off the rims, I found their casing to be thin-ish but not unnervingly so. A basic tire I would expect to work well with no special flat protection.

Continental Contact Plus City 26×2.20

I replaced the Chaoyangs with the largest flatproof tires I could get my hands on. The Contis are bigger than the Other Leading Brand best-in-class tire, the Schwalbe Marathon Plus. I know from past experience that Continental seems to be trying to beat Schwalbe by putting out comparable tires and selling them at much lower prices. I use the Contact Plus tires in 700Cx37 and they are absolutely as good as the Schwalbe competitor, but are half the price. That tread is not available in a large 26″ size, but the ‘City’ version is. And since the Marathon Plus only goes up to 26×2.0, this appears to be the biggest flatproof tire out there.

Like the other Conti tires I use, the tire casing is actually smaller than rated, and stretches over time to approach but not quite reach the rated width. At installation these tires were 2.15″ wide. After a week or so, they had stretched to 2.2″.

Why is there a caption here? You can read the label in the image.

A smaller casing is not really what you want on a cargo bike, but I expected these tires to be really solid; making up for the loss of volume. So far that expectation has been met. These tires qualify as tank treads, and they roll smooth as silk. There is enough tread articulation to make me comfortable using them in the wet, and not so much that there is any vibration of any kind while rolling.

Under load, with my 250-lb self, 140 lbs of cargo, 55 lbs of ebike and a 60 psi max inflation, the tires performed just fine without any worrisome flattening of the tire profile under load.

Some other tires I have in the parts pile:

CST Cyclops 26×2.40

Stupid cheap but well made tire that is essentially a Maxxis Hookworm – reportedly made on the same tooling as the Gen1 version of that wonderful tire. The Cyclops has thinner sidewalls but really, they are decently thick. The Hookworms are thicker still. This is a really nice, smooth roller with grippy tread articulation for a sure grip. If you want a $25 tire you can count on (I got mine on sale for $15 each), this is it.

Schwalbe Crazy Bob 26×2.35

I use these on another bike and in this size, these tires are E50 rated for moped use (says ‘moped’ right on the tire casing). They are really thick, solid tires although they lack puncture resistant belts. The bead-to-bead tread means you can heel a bike over hard with these shoes on. Not something you need with a cargo bike, but these tires are a solid choice.

Tubes

I’m not doing the tubeless thing here. Instead, I’m going for the monster bulletproof setup. The outside layer being the super thick Conti tire, with the inner layer being a slightly oversized thornproof tube.

An oversized tube is good since it does not distend/stretch as much when inflated. Long term they are less flat-prone. This particular brand of thick tube has issues with the tube separating from the valve stem if it is stretched. I am experimenting with applying Shoe Goo to reinforce this area. We’ll see.

A big part of the draw of these tubes is not only are they thorn resistant, but they also have removable valve cores, which facilitates the addition of slime into the tube.

So…

flatproof tire
Thorn resistant tube
Slime in the tube.

Hoping for no flats, ever.

The Ridiculous Lock

Nothing, and I mean nothing, is safe from a portable angle grinder. But this is as close as you can get. This setup rides in the brown bag you see in many of the pics about this bike. This 14 lb ensemble and its keys are permanently along for the ride. Details to come.

Pragmasis DIB motorcycle grade U lock
Pragmasis 13mm boron steel chain, 2 meter length
Lockitt motorcycle roundlock

This is how the bike looks when its left outside. Roundlock nooses the frame and rear wheel. U lock grabs the front wheel. four separate 2-minute cuts with an angle grinder are needed to get this bike rolling. Note if I was being smart I would have done something to get that chain off the ground.

All the bits laid out. The cloth cover for the chain has been slit at just the right spot and sealed with heat. The bag has since been lined with some custom cut foam padding so this abomination doesn’t rattle while riding.

Mongoose Envoy – Chapter 2 (Brakes)

Introduction: The Mongoose Envoy Project

Chapter 1: The Raised Rear Deck

Chapter 2: Better Brakes (You Are Here)

Chapter 3: What Kind of Motor?

Chapter 4: Motor Choice

Chapter 5: Motor Installation

Chapter 6: Misc Upgrades and Notes

Chapter 7: The Build Sheet

Chapter 8: Low Cost Builds

“My brakes are too effective”
— said Nobody, ever

I am a firm believer in Big Brakes. I learned when building a hot rod track car that everybody pours money into motor and suspension, but brake upgrades often come as an afterthought (usually accompanied by soiled underpants).

As a daily bike commuter, I also want trouble-free operation. And since what I usually ride is a big, fast, heavy ebike, I appreciate big brakes a whole lot more since I am riding a rolling worst-case scenario.

Now, the Mongoose Envoy donor bike is the subject of this series, and it is not a fast bike. It hauls lots of stuff though and thats probably worse than merely shucking speed. So far, I have loaded it with about 140 lbs of groceries in addition to my own 250 lb self. Add to that the bike’s roughly 50 lb weight. With all that, the brakes that come with this bike from the factory really have their work cut out for them.

I suppose those factory brakes are OK… If I set aside how spoiled I am with my usual upgrades. I can see they are about average for a low-cost bicycle. While I wanted to keep this bike’s cost down, a couple things pushed me to upgrade.

First, out of the box the front brake essentially did not work at all. It seems it was so poorly adjusted that all it did was caress the front rotor and do nothing to help stop the bike. This was after I adjusted the inner and outer pad positions (the stock brakes have a dial for each side) as well as the caliper on its mount.

The rear brake … well, it did apply what I would consider to be moderate pressure. A bit light but in the ballpark of what you’d expect from a cabled system. But there is a long cable run to the back of that long frame. A fair bit of my brake lever travel was eaten up by flex in the brake line, between lever and caliper. An inspection of the brake housings showed they were not lined/compressionless – not a shock given the bike’s price point, but bad news for braking.

My initial solution was a game I have played before, and I should have known better… but I wanted this bike to be low-cost, so I tried a half measure: I upgraded the calipers to Avid BB7’s (I had a spare set in my garage), which have a very good reputation. But no matter what they are still cabled brakes. I ended up wasting half a day trying to get them just right and never did.

The front brake came together quickly. It didn’t want to stay in adjustment but thats what you get with cables. Its stopping power was just fine. It was the rear brake that was a waste of time. I tried every trick in the book to get it to be effective – perfect was never an available option. Most of the blame goes to the aforementioned flexy cable housings.

And mounting them? Avid calipers use a semi-hemispherical washer set above and below the caliper to allow it to be angled if need be, and that makes its positioning options quite fluid. The height was never correct and there was always some kind of rubbing somewhere. Regardless of how I shimmed or re-jiggered it, something was not right somewhere. I like to think of myself as something of a brake whisperer – if a brake set can be finessed, I can get the wheel spinning perfectly without so much as a touch from a misaligned pad or rotor. Not this time.

So I said to hell with it and went back to my old standby. Magura MT5 hydraulic brakes. This makes my 5th set across my 2-wheeled fleet so I am pretty familiar with them. Why these brakes?

They are powerful. 4-pistons in the caliper means four clamping points onto the rotor. Its like the difference between grabbing something with one hand versus using both.
They are smooth to activate. Unlike cabled brakes, you can use one or two fingers to gently tug on hydraulic brake levers. For the Maguras, they have lots of travel so it is easy to modulate the force applied. Despite their power they are very gentle unless asked to be otherwise.
They are dirt-simple to install. Use a Magura adapter to match your rotor size and bolt the caliper directly to it. Done. The use of Magura adapters coupled to their caliper results in a perfect height every time. No shimming. No dinking around with axes and semi-hemispherical washers… just bolt it on, eyeball it to center and tighten down.
They self-adjust. Yup thats right. You centered the caliper at installation. The pads align themselves. Really. You won’t mess with them again until you wear the pads out.

Ordinarily you pair these brakes with a Magura Storm HC rotor. These rotors are 2.0mm thick, which is thicker than the typical 1.80mm thickness most rotors(including the stockers on the Mongoose) come in at. In addition to having more meat on them to do their job (a rotor is a heat sink and more metal = more heat sink) thicker rotors are less inclined to warp. In fact I’ve never seen one do that across any of my bikes and thousands of miles.

This is a fresh Magura Storm HC 203mm rotor just after installation on an ebike. Notice the heat discoloration from the brake bedding that was just performed. Also note the caliper is bolted straight onto a Magura brand adapter with no need for shims. Matching the brand on caliper, adapter and rotor makes for perfect alignment.

With all of that said, I have found a better rotor than the Storm HC – the Tektro Type 17. Its designed for downhill bikes, who need to stop under the most extreme of circumstances. These rotors are 2.3mm thick and as such are even more substantial – and even less likely to warp. They fit perfectly on a Magura braking system, with the tops of the rotor ‘waves’ matching the top of the pads, and only a hair of lower rotor surface being untouched… not because the calipers are misaligned… there’s just more rotor face than you can use.

Here is one of these monsters, installed. Note the marks left by the pads on the surface, and its noticeable thickness.

The Tektro Type 17 mated to a Magura MT5 caliper. Once again note this caliper is bolted straight down onto its adapter and fitment to the rotor is essentially perfect.

Its worth noting both the Magura and Tektro rotors discussed here are generally too thick to use with normal brake calipers. Not so with the MT5’s. And if you are guessing the extra-thick, never-warping rotors are going to last longer, you’d be guessing right. the rotor above on the orange bike… so far I can’t seem to wear it out. That bike is my daily driver and I can’t measure any wear after about a year installed. I have worn out a set of the Maguras, but it took thousands of commuting miles.

Thats nice. How Much?

So all this is wonderful. What did I spend?

I’ll give you a couple different answers on that. On every bike of mine but the Mongoose, I used the Magura MT5e brakes, which include a safety cutoff that wires into the BBSHD via the brake lever.

Here’s what an MT5 versus an MT5e lever looks like:

Note: the comparison above is deceptive as the MT5e lever appears the same size as the MT5 on the left. It ain’t. The ‘e’ lever is actually a fair bit larger.

Thats the only difference between the two brake sets, but its kind of a big one. First of all, the MT5 lever on the left is often cited as feeling cheap or unsubstantial. I do not find it so, but I understand where the sentiment comes from. Most riders who use these do so on singletrack MTB’s where there is a lot of banging around, over and up against things. On a street bike this need for durability – and bend-ability – is not so much a factor.

The lever on the right has the obvious connection that leads to your motor, so that when you depress the lever, your motor power cuts off for safety. This lever is also constructed completely differently. Its larger, made of alloy and its shape is much more… substantial. Also note the metal pin in the middle of the lever itself. This is a hinge. It allows you to gently touch the lever and activate the cutoff while not activating the brakes. This can be handy if you are using the brakes as a sort of clutch to cut the motor out during shifting (the reasons for doing this are discussed here). This second hinge also gives you a surgeon’s precision when modulating brake pressure.

Currently as I write this in October of 2019, the cheapest source for MT5 and MT5e brakesets is here. This is where I bought the MT5 brakes I have on the Mongoose. I have also bought MT5e sets here in the past. Note that while this is a web site in Germany, and you will have to pay shipping charges, they are reasonable and the prices are so low you still save money. Especially if you get a few sets of extra brake pads, which are roughly 1/3 of what you will pay for the same name brand pads in the USA.

If you are using the MT5e levers with the cutoffs, then you also need an adapter to mate their red HIGO/Julet plug to the yellow one on the Bafang motor used in this project. Those are found here.

Brakes (two options)

If you are just going the lowest cost, max-functionality route like I did, you’ll pay about $150 for a complete set of brakes (MT5 only).
If you instead go with MT5e’s (you must select the version that is “Normally Open” a.k.a. “Closer”) you are looking at around $100 per axle at the above German web site. $125 if you buy from a USA dealer (I like Planet Cyclery on EBay – they are a Magura dealer and performed a free warranty replacement for me a year after a sale). Add to that about another $30 for the cutoff adapters. So about $280 total.

Brake Caliper Adapters

Adapters for the rotors are going to run you $7 to $10 each. I used 203mm rotors front and rear so a Magura QM9 / ISH-203 in the rear and a QM5 / ISF-203 in the front. Buy these with your brakes and pads and save the shipping cost.

Rotors (two options)

I am only listing two options here in case you cannot get hold of the Tektro Type 17 rotors. Make sure they are specifically the Type 17 as Tektro makes other rotors that look almost exactly alike and are very common on the marketplace, while the 17’s are relatively rare.

Magura Storm HC rotors are meant to work with these calipers and do so just fine. They are available for about $21 at the same source as above, and at many other retailers for only a little more. The only reason I don’t use them anymore is I found something better…
Tektro Type 17 rotors are only regularly available from two sellers I am aware of, although I am certain there are more out there. The first is from seller hi-powercycles and is where I buy all of mine. The second source is at Empowered Cycles. Empowered also sells the Type 17 in a 180mm size, so if for some reason you decide you need a smaller size, they can sell you one.

Replacement Pads

You have two choices, but if you are smart, there’s only one you should pick

MT7 (type 8) pads

MT5 (type 9) pads

MT5 pads (Magura Type 9) – These 2-piece pads provide a single surface for the two caliper pistons to press into. They do provide excellent response, but the type 8’s are … more better. Plus in order to remove Type 9 pads, they have to come out the bottom of the caliper. You have to remove the caliper from the mount to make that happen. More work for you. Unless for some reason you decide you want to use the Type 9.C Comfort pads (hint: you don’t) there is no reason to use Type 9 pads past using up the set that comes with the new calipers.
MT7 Pads (Magura type 8) – These 4-piece pads are better in every way than the Type 9. Most obviously, they can be removed from the brake caliper from the top, so you just undo the screw-in retaining bolt, pull the pad out with your fingertips and slide in a new pad (they set nice and easy thanks to ingenious magnets inside the caliper). Not so obvious: the independent Type 8.P pads have been measured to add a significant increase in clamping torque to the rotor. They also come in a Type 8.R pad, which has a sintered pad compound.

Whats the Down Side?

Just one: You will have to learn how to cut and bleed brake lines. Honestly… its easy to do. But you will have to do it. Check out the videos at the bottom of this post. They are what I used to figure it out. You will need a bleed kit to get the job done.

HOWEVER…

You can cheat. Each brake set comes with 2200mm of cable, pre-bled and fully operational. Just use it. Run the cable, then loop the excess and stuff it into a handlebar bag. There’s a little for the rear and a lot for the front. I added a front rack and the little bag I have on top is where my extra cable went. Its kind of disgusting how well it works and how its so low key I could get away with just leaving it like this forever. But it is definitely a lazy kludge. I’ll do the job right some weekend or evening this winter.

Performance

ummmm. Awesome! Duh…

They are not grabby.
You never have to squeeze hard.
They don’t fade.
There is always more brake available than you need.
They are silent (the sound of Magura pads on a rotor is sometimes referred to as “blowing bubbles” and this is actually accurate. I’ll leave it to you to experience what that actually means for yourself.
The pads never need adjustment.
If you use the MT7 pads, you replace the pads without removing the caliper from the bike (and you also get a lot more clamping force as a bonus). But since the MT5 pads come with the calipers for free, use them up.
The lines do not leak. I have heard of hydraulic brake systems that leak fluid and Maguras … don’t.
These brakes use mineral oil rather than DOT hydraulic fluid… thats a big deal because DOT fluid is nasty stuff… corrosive to paint just for starters. Mineral oil, on the other hand, is harmless.