Larry vs. Harry Bullitt – Put On The Brakes!

I mean that literally. We’re going to go over choosing and putting on the brakes in this frame-up bicycle build discussion.

The Bullitt Build
1. Battery and Battery Box
2. Cargo Box
3. Brakes (you are here)
4. Front Motor & Wheel
5. Rear Motor & Drivetrain
6. Bits & Pieces

For me, the choice of brakes are easy: I use Magura MT5e brakes on all my bikes and the Lizzard King was no exception. Poke around and you will see the MT5e is arguably the best ebike brakeset on the planet – even over and above the new MT7e (which provides identical calipers and brake levers… the stickers are different, plastic caliper covers are yellow not silver and the only functional difference is slightly better pads you can buy yourself – after you wear out the perfectly good ones that come with the MT5e’s).

I also use a less expensive but better rotor, as seen in the above headliner photo. But I’m getting ahead of myself here. By and large, this is an entirely mundane brake installation, with the exception of an extra-long front brake hose, plus some tweaks on pad choice. Lets begin with the…

Hoses

For the rear axle, its a totally generic job. The brake hose simply runs along the guides of the top tube and down the non drive-side chainstay to the caliper. Zip tie the hose to the existing mounts on the frame and job done.

Well, not exactly. You will want to cut down the 2200mm hose that comes with the brakes, and unless you are very careful (it can be done and Magura shows you how in their Youtube videos) you will have to bleed the hoses after cutting them, then reattaching the sized hoses to the lever.

If you are using the standard Bullitt frame kit, you have a Satori Easy Up, which allows you to raise the handlebars temporarily so you don’t bonk a passenger on the head with your handlebars as you ride. When you size your brake hoses, do so with the Easy Up fully extended.


Its the front mount that needs special attention. On a normal Bullitt, running the hose the way Larry Vs. Harry intended, they specify a 2350mm hose length. I heard 2750mm in a discussion with Splendid Cycles, and I think they are more right than wrong by going long. Either number is well beyond the 2200mm provided with the Maguras in their caliper/hose/lever kit.

Note:
My needs for running brake hose from the front wheel are different than most because I had a battery box where a normal Bullitt would run its brake hose.

So this is going to be one long hose; longer than is needed on a tandem, so you are going to have limited options. If you dig around, you will find a few sources for extra long hoses. You may hear the recommendation to use one of a couple of extension solutions that use a butt-end connector to bridge two hoses. These will work, but I won’t discuss them because thankfully, I found other options:

Jagwire Pro Hydraulic MTB Hose Kit

This can be purchased on Amazon and comes with a single 3000mm hose. You are supposed to cut that 3000mm somewhere in the middle so it is enough brake hose for both your front and rear brakes. On a normal bike thats plenty of hose for front and rear. For a Bullitt its enough for the front only. You will also have to buy the hose end kit for your brand of brakes. Naturally, those are sold separately. I bought this one for Magura brakes. It should be noted the only reason I bought this is because – most likely thanks to COVID shipping delays and general global chaos across the planet – the next option listed was taking months to deliver. In the end I didn’t use this Jagwire kit because the following finally arrived:

Custom Hoses (from Austria)

Via Ebay from seller ‘judma‘. There is no telling how long this link will last… The green ones I bought are already gone and only orange and white remain for sale (for now? Maybe they’ll come back?). I didn’t want colored hoses so much as I wanted 1-piece hoses, and this seller had a particularly useful option: I could specify the custom length of each hose. So I specified 3000mm (I actually got about 2950) for the front and a lesser, specific size for the rear. Since these hosesalready had the ends properly machine-pressed on, I opted to use them. However the neon green was a little too bright. I toned it down by covering it with dull green heatshrink tubing, from the caliper to where it entered the cargo area (more on that later) and with black heatshrink after its exit into the sunshine near the handlebars. These hoses turned out to be of top quality.

A blindingly Neon green brake hose gets toned down with a dull green heatshrink as a permanent cover.

UPDATE: An Alternate Path

In discussions about this article on the Bullitt – the Dark Side group on Facebook (thanks to Arild V. for bringing this up), it was pointed out Magura sells extension hoses alone in 2500mm lengths. Thats another avenue to the same goal, then: Buy an MT5e kit, still (buying a lever and a caliper outside of the kit is much more money than just buying the kit and stashing the hose that comes with it for some future project). Then buy a 2500mm 90-degree hose. Substitute this hose for the one in the kit. You will have to have a complete bleed kit and all tools necessary to redo Magura brake hoses (you should have this anyway).

If you live in the USA like I do, this is nowhere near as attractive of an option as it is in the EU. Magura brakes and parts are double or triple the cost here. This 2500mm Magura hose in the USA runs about US$65-US$70.

After this discussion I decided to go measure my brake hose on the bike to figure out just how much I cut it down from its original 2950mm. I came up with 2670mm. Could 2500mm work? I’m sure it can for a normal Bullitt. When looking at my hose lengths, remember I had to re-route due to the battery box. This means the hose exits the corner of the cargo box and runs around (and is protected within) the concave rear edge of the honeycomb floor. It comes forward to the steering tube from the inner rear edge of that floor and only then begins its run up the steering tube. That adds several centimeters to the necessary hose length…

Which I didn’t care about as I had plenty of hose to start with. If I had only 2500mm to work with, I’m not certain I could have made internal routing work. Something for you to take into account and puzzle through when you do your own project.

Worth Noting

In my initial build, up front I was able to make the stock 2200mm hose that comes with the Magura MT5e brake kits work – and work pretty well. Look at the picture above and pretend you are seeing the stock black hose… I ran the cabling inside thru the cargo bay as you see above, and let it sit naturally along the lower edge of the floor (it’ll stay in the channel created by the edge of the honeycomb floorboard just fine). As it curves back up to the handlebars along the back of the cargo box, it did so in an arc right along the rear bulkhead. Flush to it. Nothing sticking out.

Fitment was fine, with nothing really extra but nothing stretched, either. The hosecame up along the rear wall, out of the cargo box along the extended handlebar stem and then to the brake lever. I added a couple of zip ties to keep it snug to other hoses and completely unnoticeable.

I ran the brakes this way for a couple of weeks while I waited for the longer cabling to show up, and I could have lived with it being like that permanently if I had to. However, if I had needed to raise the Easy Up to accommodate a passenger I might not have been so sanguine about this lazy solution.

Rotors & Pads

The choice of rotors to go with the MT5e’s is a little gimmick I really like. Generally bike owners shopping for rotors only concern themselves with rotor diameter. 160mm, 180mm, 203mm… those numbers sound familiar, right? But what about how thick the rotor is? Well, Tektro type 17 rotors are 2.3mm thick.

So what?

Your typical bike brake rotor is 1.8mm thick. Some brands will shave that down to as little as 1.4mm (Avid rotors were thin like this years ago when I was still using them). A thin rotor is lighter and thats nice for your skinny analog road bike. But a great big ebike? Not so much. You want meat on those rotors just like you want great big brake rotors on your race car. Brake rotors are heat sinks and braking is the process of converting momentum to heat. The more rotor you have the more heat it can absorb. The beefier and thicker your brake rotors are, the more it takes to warp them. Or for that matter wear them out.

My initial front wheel build used a 180mm Magura MDR-C rotor

So, one of the reasons I like Magura calipers is they are designed to take an unusually thick 2.1mm Magura brand rotor. Great. The Magura Storm HC rotor, or its new beefier cousin the MDR-C, are designed for the MT5e/MT7e, and vice-versa. These 2.1mm rotors are considered worn-out when they get to 1.8mm – thats the size most other rotors are sold new. Magura calipers should NOT be used with thinner industry-standard rotors. Thinner rotors extend the pistons too far and could cause them to leak. Do not ask me how I know this.

But what about thicker ones?

At last! We get to the point. I’m using 2.3mm thick Tektro rotors, which were originally meant for the small niche of downhill MTB bikes. Now they are sold by the boatload as ebike rotors with Tektro’s newfangled ebike brake kits.

Is 2.3mm too much for the Magura caliper? Almost, but it works. Since I have so many sets of Magura brakes on The Pacific Fleet, I can pull a set of partially used pads off of one of them, plug those still-usable pads into a new bike build, and let the slightly worn pads give me an extra skootch of clearance. When these pads have worn down and need to be replaced, the fat rotor is now worn a bit and can handle fresh pads easily.

I have yet to wear out one of these Type 17 rotors down to 1.8mm thickness, which is not something to complain about.

On the Front

So, on the front wheel the rotor is the 203mm size. Thats a lot of rotor for a 20″ wheel. I initially used a 180mm Magura MDR-C, coupled to Type 9 Performance (Black) pads. those are the ones that come with new MT5e calipers. I found this combo could easily lock up that poor little front wheel. I was already building another custom front wheel, so the final wheel build used a bigger 203mm Type 17 (even more stopping power, which is not so great) but with downgraded Magura Type 9 Comfort (Blue) pads – a lot less stopping power but great modulation and longer lasting.

My original – now backup – wheel is waiting in the wings with a Tektro rotor already installed. I’ll swap it onto the bike soon so I can take the primary motor apart and regrease it without disabling the bike in the process.

The pads were expected to be so much less aggressive that they would more than make up for the bigger rotor, and thats exactly what happened. I still have strong braking performance on that front wheel but now its very nicely modulated so I can clamp down hard without locking up the front wheel and making a spectacle of myself.

Since the Comfort/Blue pad compound is not sold in a Type 8 4-piece pad, I considered replacing them once they wore out with the Type 8S (Green) ebike pads. Still a step down from the Performance/Black compound, but the 4-piece pad config would step up the torque the calipers can apply to the rotor. Hopefully not too much.

That was the plan, and maybe it is something you want to try with your build. But the day I was to publish this post, I performed front wheel maintenance on the bike and saw the pads are down to about 1.5mm already – time to replace them in a couple weeks. The market is such that the Type 8 green pads are very pricey, and the Type 9 pads are dirt cheap from a German bike site. So what the hell I stuck with what I know already and bought 3 sets, along with another cheap Super Moto X tire (also very pricey if bought from a USA source) to soak up the $20 shipping charge and still keep me ahead of the game on costs.

On the Back

The rear rotor is, at present, a Magura Storm HC 203mm rotor. Its a solid choice for a rotor, and of course its the go-to until recently for a factory-matched kit. Why use it instead of the Type 17? Frankly it was in my parts pile and needed to get used up. So instead of playing the pad-swap game described above to fit a fat Tektro rotor, I put on a factory rotor and we’ll wear down the pads some thataway. After 1000 miles on the bike, it is already down to 1.9mm from its original 2.1mm. It won’t be long. Don’t blame the rotor: cargo biking is as severe of a duty cycle as you can get. I use the rear brakes as my primary stoppers with the fronts eased in after the rears engage. I get well-balanced rear brake wear as a result.

This 203mm rotor is taking a beating and will be replaced sooner rather than later with another of the big Tektro’s

Out back I am using the standard-issue Magura Type 9.P pads – the black Performance compound. Ordinarily I only use the Type 9’s initially as they come with the new calipers. I then replace with the more torque-y Type 8.P’s from then on. But here again I have Type 9’s in my parts pile so I am just using this bike to run through them. They work just fine, although to replace them or check pad wear you have to remove the caliper from its mount, which is one more reason why you want to use MT7 pads (a.k.a. “Type 8”) in your otherwise-identical MT5 calipers.

Brake Cutoffs

This bike has a Bafang mid drive powering the back axle, and a Bafang hub motor with KT controller powering the front. In my 2wd twin-hub-motor builds, I split the cutoff signal from one lever to both controllers on each lever, so actuating either lever alone cuts both motors.

I learned with the 2Fat build that trying this with a BBSHD and a KT hub controller bricks both motors – they never can start in the first place. I tried every kind of setting or workaround and they have to be entirely separate circuits or you get no motor power period.

Trying it again on this Bullitt build, a few years later: same result. The solution is for the rear brake lever to cut the rear mid drive and the front lever to cut the front hub.

One difference from the past is now, in 2021 I am able to buy a BBSHD wiring harness designed to use Magura’s red Higo/Julet plugs natively without messing around with finding or fitting adapters. Otherwise, you have to buy red-to-yellow Higo/Julet conversion plugs. Before the above direct connection wiring harness existed, I used these little jewels.


Thats it for the brakes. Lets talk about

The Front Motor and Wheel

Larry vs. Harry Bullitt – the Battery (Box)

A big bike with two motors needs a big battery. Lets take advantage of the frontloader design to both hide and secure it.

The Bullitt Build
1. Battery and Battery Box (you are here)
2. Cargo Box
3. Brakes
4. Front Motor & Wheel
5. Rear Motor & Drivetrain
6. Bits & Pieces

A big issue with an ebike – particularly one that is left outside on its own all the time – is battery security. The battery is maybe the most expensive component on an ebike and its a big theft target. So typically you have to carry the thing inside with you, and hey… thats a real pain in the neck. Not only is it a really heavy black brick, but you have to dismount it and re-mount it to the bike, and disconnect and reconnect it to the motor (forget about your display keeping the correct time and date), every single time. I have come up with my own way to make the best of this bad situation for my other cargo bikes, but with the Bullitt, we can make the problem go away.

The Kinda-Secret Compartment

Take a look at the picture above. See the big black box under the cargo area, near the ground? Thats it: the battery box. You’d be surprised by how many people don’t notice it. Even if they do, what are they going to do about it?

I had seen a few other Bullitt builds with battery boxes and they seemed like great ideas: The battery goes out of sight, out of mind under the floor of the bike. It lets you get creative on battery size (as in you can go bigger if you like since there’s lots of room down there). It may even be made secure enough that you can just leave it on the bike – eliminating maybe the biggest inconvenience of using an ebike for daily errands and shopping.

Also, just as with electric auto designs, a ‘skateboard’ config for the battery puts it centered and below the floor – down as low as it can go. That is as good as it can get for performance.

But I was thinking of none of these things when I was putting together my build sheet. I was still thinking I would do another quick-carry sling pack with the battery inside, and toss that pack into the cargo bay for easy removal and replacement. It wouldn’t be secured to anything but I would see about figuring that out later on.

My sling pack with a 20ah battery inside, used on my Surly Big Fat Dummy

But while the parts were still trickling in, I was participating in a discussion on the Bullitt Universal Owners Group on Facebook. Another Bullitt owner showed off his own build and mentioned his battery box – and that he had gotten it from Splendid Cycles – the same shop where I got my Bullitt frame and parts. I gave them a call and in short order one of the last examples they had on hand was on its way to me. I was told up front the box was a blank canvas, and I would need my own elbow grease to add mounting holes and any other refinements, such as waterproofing, cable exits etc.

As-delivered, the battery box looked as you see it below. A simple slot holds it up on the back. Its front at first seems unnecessarily complicated, but is quite clever. Its seamless, unbroken face prevents any direct channel for water ingress from the front, just behind the tire. The cutouts necessary to let the box slide into place doubled as my exit points for the power, charging and temperature sensor cables, so no need to cut any holes. It fits absolutely flush to the near side of the frame so no insulation is needed or wanted. Its shape is angled on one side to clear the steering tube.

The box as-delivered, almost. I used black flexible silicone sealant to all the internal seams, and dabbed over all of the rivets as well.

Box Installation

The first step was to drill the box so it could be fixed in place. As-designed, it would stay put. But I am sure there would be some shifting and rattling… and I can’t abide rattles. Also, the existence of the box complicated the installation of the honeycomb floorboard. The floorboard expects to be able to drop a bolt straight down and use a nut underneath to lock it down. Well, now that bolt hole is completely inside the box on the front left corner. Its outside on the right front, but not by much. I needed to change those two mounts to fixed studs going from the bottom up.

I also wanted to add an entirely separate bolt on the front dedicated to strongly fixing the box in place. I decided to use an oversized hole, and used a hand file to enlarge it to a rectangle. Following that, a combination of an oversized, hardened washer and a flush-fit M8 bolt gives a flat fit that works under the honeycomb board fitting directly down on top of it.

The new ‘studs’ are common, long M6 socket caps with – get this – a Presta valve nut to hold them in place. I needed a low profile nut and there’s nothing lower-profile than the common presta nut, which even fits snugly inside the bolt hole manufactured into the LvH honeycomb board.

Forward box mounting complete. Two studs are ready for the honeycomb board, and the center bolt holds the box tight to the frame.

For the rear of the box, to match up with the honeycomb board’s rear mounting hole, I had to use another M6 rather than go with another big M8. I drilled a thin hole thru the box’s top flap and the honeycomb board’s rear mounting bolt goes thru there. However to be consistent – because I wanted to use security nuts to make getting into the box that much more difficult – I made it go in from the bottom-up like the others (we’ll show those security nuts etc. in more detail when we talk about the cargo box installation).

Now Install The Battery

At this point, the next step in the installation process – which, maddeningly, has to be done in this order whether you like it or not – was to install the battery.

You can see how I accomplished that below. All of the padding is closed-cell, and I left as much of the battery untouched by foam as I could. The battery lays on the bare alloy of the box with no padding (a solid metal wall is plenty of protection). It is surrounded on four sides such that it cannot move, even after months of pothole pounding commutes and store visits. I disassembled the bike after 500 miles and looked inside to be sure of this. No water had gotten in either despite riding in rainstorms.

There is a brake cable braze-on above the pack underneath the center bar. It is perfectly positioned to smash into the cells underneath if the pack bounces up to meet it. I prevented this possibility via some left over Minicel T600 EVA foam (you’ll see what I used it for in the Cargo Box episode) to fix the battery in position (i.e. keep it from bouncing). Two pieces are used, one on each side of the braze-on. Underneath this area the visible green rectangle is a piece of thin metal fence strapping which provides a last but certain line of defense against that braze-on ever contacting the bare pack.

The battery is literally incapable of movement on any axis. It is held solidly – but not enough to smoosh anything. Rapping on the box with your knuckles yields a satisfying thunk as if you are rapping on a solid block of metal.

Notice the short extensions in the pics above? There are two lengths of them in use (strictly speaking there are three as we need two when we split the power to run to both motors). I don’t like to make direct connections to wiring that is a hassle to repair – like wires that run hot directly from the battery. I want to be using a short extension on each side of a connection for two reasons. 1: So the wear and tear occurs on something that is easy and painless to replace if it wears out. 2. If something terrible happens like a short, the melted connector is on an extension and can be easily unplugged, thrown away and replaced. No need to be working on live wires to salvage the battery (assuming a short doesn’t cause other problems with the pack itself).

I have had one occasion where this saved my bacon when an XT60 extension shorted on a water bottle bolt head. There was no damage other than to the destroyed cheapie extension. In this case, there is no issue of frequent connects and disconnects, but the habit of using extensions for the safety angle is hard to break.

Lets Talk About The Battery

An AWD bike needs a lot of power. Even one where I have toned down the power to civilized levels. You must have a pack whose Battery Management System is strong enough to run two motors at once, and if you get into the subject and learn the specifics, you will find out real fast that commercially-manufactured battery packs can’t cut the mustard (this is why commercial AWD bikes have two separate batteries). If you want to build the bike right as opposed to building it cheap and sucky, you have to get yourself a custom pack built that is tailored to the job.

Pack Details

The battery itself was built custom to my specs after some discussion with Matt Bzura at Bicycle Motorworks. This is one of several packs I have purchased from his firm, after hearing nothing but good things about his work from other builders over the span of a few years. I’ve had nothing but good experience working with him as well.

I knew that an AWD bike needs more power, so the battery pack needs to be bigger than usual. And the Splendid Cycles battery box is a big sucker. If I put in a battery that filled that box it would be TOO big. Looking at the box dimensions and knowing what I wanted to do for crash padding gave me one half of the picture. Matt @ BicycleMotorworks filled in the blanks with the dimensional details of the cells and battery management system chosen for the job.

Cells Samsung 40T (21700’s)
Pack Config 14S8P (52v)
BMS Capacity 70a Continuous output
Amp Hours32
Output CableXT90S / 8ga
Charge CableXT60 / 12 ga

The 40T cells in the larger 21700 size, and overall pack design allows it to operate under load without voltage sag, and without heating up, despite the enclosed space and the dense, closed cell padding that holds the pack fast. A temperature sensor is attached to the pack top and runs outside of the box for easy visibility from the saddle.

What About Heat? 
In use in a normal climate - bearing in mind its sealed in a big metal box - the pack does not get noticeably warm over and above ambient air temperature - nothing over 5 degrees Fahrenheit above ambient.  However, 5 degrees over ambient is a lot when its 105 in the shade, where in the sun, the pavement is radiating heat at 130.   In severe heat (as I write this, the end of next week is scheduled to reach 114°F, which is more than 45°C) I need to plan ahead for where the bike is going to be parked, and plan my route to provide the shortest, shadiest path to my destination.  Our local area has already experienced several days where the temperature has exceeded 110°F / 43°C. Even though the battery cells are not thermally coupled to the case, I ringed the box with heat sinks to help keep the pack a bit closer to ambient temperature.  They have reduced pack surface temperature by up to 5 degrees. 

The battery charge cable is routed outside of the box along with the power cables, and comes up as shown in the photo below (the green plug). This plug is semi-rigid thanks to the manner in which I insulated the end connector, as well as how its braced against other secured wiring. It is easy to access, protected from the elements via the plug cap and not going anywhere. In winter months a rubber band and some plastic will ensure nothing can get through and cause any fireworks.

And last but not least… this is a 52v battery that has a capacity of 32 amp hours. I like having batteries big enough that range anxiety doesn’t exist. You simply go ride the bike and do what you need to do. Considering the bike – thanks to its motor configs – eats only 400-500w at cruise… my ass will wear out in the seat before the battery charge does…

So long as I remember to charge it. But even then – and this has happened to me already – the battery is big enough to maybe rescue me from that faux pas.

The battery temp sensor sits here, without any need for actual mounting. The Bullitt’s ride is so stable nothing more is required. The charger plug is covered in a green cap at center.

Thats about all I have on the battery and battery box. We’ll stick to the same area of the bike in the next article in the series, as the two are linked together:

The Cargo Box

The Bullitt, by Larry vs. Harry – Cargo Bike Build

And now for something completely different. The Bullitt from Larry vs. Harry is a bucket list bike that (now that its finally done) I love to ride. This series will cover the details of a frame-up build that includes AWD electrification.

The Bullitt Build (you are here)
1. Battery and Battery Box
2. Cargo Box
3. Brakes
4. Front Motor & Wheel
5. Rear Motor & Drivetrain
6. Bits & Pieces

Originally, this was going to be a single article that covered everything. However, as time progressed and I got more and more of the details written down, I found I was at almost 6800 words, and could easily hit 8-10,000 before completion. Thats too damn big, so it had to be broken up. This opening post will cover some of the introductory bits. Then we’ll split off into followups that hit the high points of the various things worth bringing up.

There’s a lot to get to so lets jump in.

Background

Having built up the Mongoose Envoy as my first cargo bike, then supersizing to the Surly Big Fat Dummy, you would think the Larry vs. Harry Bullitt was my third choice for a cargo bike. It was the opposite: The Bullitt was my first choice. But first,

What the hell is a Bullitt?

A Bullitt is a bakfiets. How does me saying that help you? It doesn’t, until I add that bakfiets is a Dutch term that means “box bike”. You’ll be helped along a bit more by the fact that a bakfiets is often referred to in English as a ‘frontloader’. So, the box is in front of the rider. Here is a Google image search that will let you see a slew of them, of all different types.

Looking at all those different pictures, they all look sort of like 2- or 3-wheeled dump trucks. Not exactly a fun ride. But thats to be expected of freight haulers, right?

So, What the hell is a Bullitt?

A Bullitt is a frontloader-style cargo bike made by Larry vs. Harry in Copenhagen, Denmark. It does its cargo carrying job, but its also specifically designed to be nimble, on a frame that is relatively rigid. Its also meant to be those things in a lightweight package, where that frame is lightweight alloy (whose inherent rigidity is mitigated by the sheer length of the frame. A Bullitt is also a very comfortable bike to ride).

In short, the Bullitt is a cargo bike for people who still want to have fun riding their bike. You aren’t schlepping around in the bicycle equivalent of a minivan.

This gets the idea across in 1 minute.

When I originally decided to build up a Bullitt, I set up my build sheet and began listing out components. But before I finished, the cost crossed my pain threshold and I chickened out. This was going to be my first cargo bike. I had no experience with the platform, and wasn’t even sure I would like the idea, never mind throwing in the funkiness of a frontloader. I wasn’t ready to make such a big financial commitment.

So I went the budget route with the Mongoose Envoy. I used that frame and fork as a donor platform to develop a really nice lower-cost cargo solution. After some use I decided 1)this whole cargo bike thing was really cool and 2)the Envoy wasn’t big enough for the XXL jobs I wanted to give it.

When I was doing my research prior to buying the Envoy, I had almost bought the much larger Surly Big Fat Dummy, but bailed on that one too due to the same kinds of newbie uncertainties that led me to bail on the Bullitt project.

So, wanting to upsize, I went there next. That bike has been a thing of beauty. I loved it and still do for a variety of reasons beyond its utility as a cargo bike (and a bikepacking bike. And a take-the-trails-route-instead commuter. And an unstoppable freight train that terrifies all who cross its path). The Big Fat Dummy truly is a BFD.

But…

Using the BFD for all things, every day, I could see room for improvement. Stuff that bugged me and worse – slowed me down.

At the shops, you have to bring the battery in with you or risk getting it stolen. I had a solution for this but it still takes effort to deal with and is a pain. Additionally it limits the size of the battery as the bigger it is, the more trouble it is to carry around.

The BFD has two panniers that hold more than 275L (not 27.5… Two Hundred and Seventy Five). Who can ask for more? Except bags that big aren’t kept opened up and ready for use. They’re folded up and strapped to the frame. Expanding them requires some fussing and fiddling with the straps. Not the end of the world but it has to be done. And then you need to cinch those four to six straps down to secure the load. And balance your load between the bags or bad things can happen. When you are doing this every day at multiple stops, you start wanting things to be easier… but how?

Enter The Dragon

A Bullitt from Larry vs. Harry. Thats how. A bike purpose-built for a narrow type of use-case: urban utility. The Bullitt is the most nimble and rigidly-framed of the genre: the sports car of the frontloader world. The battery on this bike will be locked in a quasi-concealed, sealed box under the cargo floor of the bike; out of sight from prying eyes and prybars. No more lugging it into the store with me. Most importantly, the bike has a floor in the first place. Cargo is held in a great big open box. I can just walk up, dump my shit in and and take off. No more pre-flight prep.

Also I kind of liked that it looked weird… and I had no idea whether I could ride such a contraption. I don’t get that kind of uncertainty with bikes much these days and I looked forward to the challenge.

Oh, and since LvH decided to call the green paint on the bike Lizzard King, well that makes for an obvious name for the bike.

Bullitts are – wonderfully – built up from frames and customized by a great many of their owners. So even though I am doing a lot of writing-up here, there’s not much point in doing full how-to’s, since thats how most everyone does it already, anyway. So my focus will for the most part be more of a high-level one rather than getting down and into the finer details of Tab A inserting into Slot B etc.

What a mess! A month or so after initial build completion my custom battery arrived… time to take it back apart!

So Lets Build It Already!

So much going on… Where do we start?

The Frame Kit

Your local Larry vs. Harry dealer will happily sell you a complete bike, or even one whose frame has been purpose-built to integrate an electric motor. You can choose an internally geared hub, and the frame has a split in it to allow a belt drive. Lots of options for a complete bike, or buy their frame kit and build your own.

I chose the frame kit route. The kit comes with the frame, fork, steering arm, headsets (plural) installed and a number of other components that are unique to a Bullitt’s construction, so you don’t have to go searching all over creation for weird parts. I also purchased the “honeycomb floor board” (the cargo deck) and the “side panels” (hard sides to the cargo area that turn it into a big bucket). It all arrived in one giant box, too big for UPS so it was a LTL freight carrier in a full sized semi-hauler that brought it in. The truck was so big it had to meet me on the street.

I purchased the frame kit from Splendid Cycles up in Portland, Oregon. I handled the transaction entirely over the phone and the folks at Splendid were both helpful and generous with their time, answering my technical and build questions and making sure I was taken care of. Delivery was prompt and I was frankly amazed at how well the frame was packaged once I got the box opened up. Oddly enough I met the tech who packed my frame online, in the Bullitt Facebook group, who was happy to see I got the frame and confirmed what was visually obvious: he had spent time making sure it was packed well so it would get to me in the same shape it left their shop.

All Wheel Drive

Even though the bike only took me about a month to build so it was at least roadworthy, there was a lot going on with this bike. Most of the reason it was such a pain revolved around this one feature. In the end, it was worth it, but the added complexity of an AWD ebike is not for the faint of heart.

Two-motor AWD means wires everywhere. Hiding them is something of an art form.

I have built several all wheel drive ebikes, but not recently. I decided the Bullitt was going to be the proof-of-concept behind a different, more civilized/everyman form of ebike AWD that I had been mulling over for years but never did anything about. That subject, the merits of an AWD ebike and the specifics surrounding it are all dealt with in a separate case study in my dual-motor AWD ebike series. I’ll let that post and its companions stand on their own and just say that the sort of cooperative, drama-free AWD that was put into the Bullitt is, in my estimation, a tremendous success with regard to making it a viable all-day, everyday auto replacement.


Which leads us straight into the next episode:

The Battery (and Battery Box)

BBSHD Aftermarket Controller Bracketology

Seeding BBSHD aftermarket controllers has gotten more complicated in 2021. The 2021 choices have seen BBSHD market gorilla Luna up their controller game. To take on start up ERT in the F.O.C category, Luna has recently beta tested their Ludi V2 BBSHD controller. Luna explicitly states to “use this controller in off road only situations”.

The gray wire is an antenna for VESC dashboard & upgrades via Bluetooth on Android device.

I installed a Luna Ludi V2 FOC controller on my Specialized Pitch BBSHD conversion that utilizes a 42T Eclipse and wears Schwalbe 27.5 Moto X tires. Prior to upgrading the controller, the Luna 860c display showed a little over 30 hrs of riding time. I ride the same 25mi route of asphalt with this bike. It’s powered by a Luna Dire Wolf 52v 21aH battery that contains  84 LG MJ-1 18650 cells configured 14s6p.

I love this bike! It’s nimble and has crazy long range via 21aH Dire Wolf. It’s even color matched!

My commuter routine is about 12 mi asphalt in AM. Charge at work to 80%. Then ride home same route. Without changing gearing between the stock BBSHD controller loaded with Karl’s Sauce Settings and the Luna Ludi V2 controller, I have gained about 8 mph top end speed and my battery consumption has remain the same or slightly decreased.

The only issue so far with the controller upgrade is that the battery indicator goes red during acceleration or hill climbs when below about 50v. Previously the stock controller with Karl’s settings at the same mph and same gear selection did not trip the battery icon to red on the Luna 860c display .

On average, I am consuming about 3v less of total battery upon arrival at work, which is the 12 mi mark, before charging the battery to 80% using the Luna battery charger. My transit time is about 45 minutes to work and is nearly all ghost pedaling.

I am basically maintaining the same speed covering the same distance arriving at the same time to work but using less battery. This is possible because I am using less wattage/requiring less PAS as observed on the display.

Best 1st build BBSHD platform is a Thud Buster seat post on a mechanical discs hard tail frame.

The efficiencies can not be attributable to becoming a better ebike rider; getting more efficient in gear selection, braking, running stop light etc. If anything, I have greatly decreased gear changes. I am staying in my most effective cassette gear of 24T, 3rd biggest cassette gear, and not downshifting to provide more leg drive. 24T provides maximum chain wrap with out stripping. The previous 25hr of bike time I stripped out the lower tooth gears to the point I can’t use them under BBSHD power or human only power; the chain just skips terrible in those smaller cogs due to not enough chain wrap and the cassette teeth being worn down.

How much did I pay? This was beta and I did pay my own $. This is not available stand alone from Luna right now. If you want the Luna Ludi V2 FOC controller you have to buy a Luna BBSHD bike. In the past I did buy a Luna Ludi V1 controller for over $200 and I did buy an ERT NXT BAC 855 BBSHD kit for over $500. This beta was somewhere in between.

Make double sure you have the phase wire spade connectors seated properly to the BBSHD.

Is the Luna Ludi V2 desirable? YES!!! At the very least you can extend the range of your current battery. You can get more top end out of your bike and using throttle only you can reach a higher mph.

It was very straight forward to install. I have previously removed BBSHD controllers. I am familiar with how the PAS clip and 6 halls/temp clip operate etc. After you get familiar with this, it took under 1 hour to remove the stock BBSHD controller and install the Luna Ludi V2. It took about 10 minutes to silicone/water proof the connections.

Pro Tip!! When connecting the 3 BBSHD phase connection spade connectors, make double sure the spade goes into the female socket …… Plus look at the 4 pin PAS and 6 PIN halls/temp connector on your V2. Hints can be found how to disconnect your stock controller by actuating the retainer clip of the connector. When you disconnect wiring looms do you generally just grab and yank??!! No. Look at what came with the kit and carefully disconnect the stock controller by actuating the retainer tangs!

2nd Pro Tip!! Elevate the bike. Hang your bike by the front wheel and try to get the BBSHD/bottom bracket as close to eye level as possible. I had the luxury of a ceiling hoist. But you can use your garage door track or a ceiling hook as well. This will make it much easier to remove the stock controller and install the upgrade after mkt controller. You have to water proof all connection in the BBSHD before screwing down the controller and this is much easier at eye level.

It’s a tight fit to get everything folded back properly and the controller fastened to the BBSHD.

Luna has posted a firmware update. Using the VESC app, my nephew flashed the controller wirelessly using his Android phone and the blue tooth connection via the small antenna sticking out of the controller case. The flash upgrade included a pseudo-motor idle function that helps keep the chain semi-tight when letting off the throttle, helping to reduce chain slap. The amount of idle is increased by increasing the PAS level.

Performance into a 15MPH wind flat ground 55v at full sag during these observations.

Throttle only in PAS 5 and the biggest cassette gear of 34T gives 25MPH at 800 Watts; over 30+MPH at 1200 Watts. Full throttle made the LUNA Dire Wolf battery icon go red so I did not hold it there long but it was very fast acceleration and speed.

PAS 5 ghost pedaling and the biggest cassette gear of 34T gives 16.5MPH at 500 Watts; 24T gives 22.5MPH at 500 Watts.

In PAS the speed controller would stick to a MPH level and increase or decrease the Watts to maintain that speed; almost like a governor.

The BBSHD never got too hot to hold your hand on the motor or the controller. The motor never got hotter than 110 F.

Overall the Luna Ludi V2 is very good. It’s $ well spent even if just considering the battery range extension. If you are looking to scooter throttle only you won’t be disappointed in acceleration and top speed. As a PAS ghost peddler, it does not seem that different from the stock Bafang controller loaded up with Karl’s Sauce Settings. VESC app analytics dashboard looks cool but I don’t have an Android device nor the time to play around with those features. Luna warns not to change parameters on the controller without considering the consequences and locked out some of the most dangerous ones to the motor and rider.

P.S. At the time of publishing another field weakened BBSHD after market controller has burst on the scene. Enthusiasts of ASI BAC 855 have banded together via Discord collaboration to present a potential product challenge to Luna Ludi V2. The High Voltage team of Captain Codswallop, Mike and Greg bring a formidable grass roots business plan. I’ve done business with Captain on 3D printing for ebike items and was blown away at the exceptional level of quality and customer service. Captain told me High Voltage is “…new to the market but are providing a high quality product that customers are very happy with…focus…on customer service and quality. We are looking to expand to other motors in the near future.”

The High Voltage brand graphic to look for on authentic products:

BBSHD Performance Settings (slightly refined)

In BBSHD Programming for the Pedaling Cyclist, I laid out what my preferred settings were for my ebikes. I have settled upon them after a fair bit of tinkering over time. Since that was published, I have made some refinements.

I’m going to skip all the background I went into before. None of those details have changed. I’ll just note what I have done, and what it seems to accomplish.

Remember, There is no one perfect suite of settings for the Bafang BBSxx series of motors. Most likely, your perfect setup will take a bit from here and a piece from there to give you exactly what you want. Use what you see here as a basis for your own experimentation.

In fact, I don’t even have a single flavor I stick to as you will see below.

The Basic Screen

From then to now, I changed nothing on this screen, and I’m only showing it here to give you a complete settings reference in one place.

Figure 1: There actually is one change from the past but its only visual: the 30a current limit. The screen said 25a last time and that was not something I ever stuck with.

The Pedal Assist Screen

There are several changes here, all geared to toning things down and making behavior more gentle. I have two versions of this screen in play on different bikes. The first is the more general-use, but the things I get from Version 2 could be very desirable on any bike.

I can’t say enough that there is no one best choice of settings for your BBSxx motor.

Version 1

Figure 2: Before on the Left, After on the right

Pedal Sensor Type

Ignore this one unless you are in the mood to play around and see whats what. Some motors come programmed with BB-Sensor-32, others with DoubleSignal-24. This is something I just leave as-is depending on what the motor originally came with. Frankly its not a setting I know much about so I don’t fool with it.

Start Current

This has been reduced to 4 from 6. Start Current dictates how much juice goes to the PAS system when it initiates. A lower number means a lower ‘jerk’ on the drivetrain as the PAS system engages. This is a percentage number, so we are going from 6% to 4%. Restated, that is from ‘very gentle’ to ‘mouse-fart’! Still, as small of a change as is indicated by the numbers, its a noticeable decrease. Bear in mind I am riding some pretty big fat and cargo bikes and when starting a bike with a heavy load, a little less is much more.

Also don’t forget no setting is an island unto itself. These things taken together make up a whole, and its that whole that matters.

Start Degree

This has been increased from 4 all the way up to 10. Start Degree is the number of signal points that are crossed (as you turn the crankarms) before pedal assist engages. A full rotation of the crankarms equals 24 signals, so I have kicked up the pedal assist engagement from a 1/6 turn to almost a half-turn.

This comes in handy when I am at a stop light, but I stopped smart, several car lengths back from the actual edge of the intersection. I can then stay in the saddle, balanced with feet on the pedals. I slowly turn the crankarms a bit at a time to maintain my balance and crawl forward. If I do it right, the light turns green before I reach the edge of the intersection, whereupon I can hit the throttle and move forward without having to dismount (and then re-mount) the bike. If I decide not to use throttle and pedal my way out, I’ll need about a half turn to re-engage assist, and when it comes on it will be a very gentle ramp-up in part thanks to the new lesser Start Current above.

Current Decay

I have set this to maximum now, meaning the system pretty much doesn’t want to cut back power as my cadence increases; virtually disabling the cut-back feature from the Basic screen, which conserves power (if you can spin the crankarms superfast, you don’t need assist). This is a setting I will very likely continue to play with. If I set it to the minimum of 1, then the motor will aggressively reduce the provided power as cadence increases. A lower setting is much more in tune with the pedelec ‘philosophy’ which I usually stick to. So don’t be too surprised if you come back in a month and this text has been supplemented with talk of a different, much lower setting.

Why did I change it? Just playing around. I’m leaving it here to illustrate that these settings often interact with one another in some big ways.

Version 2

Version 2 is a riff on Version 1 above. Its what I use on my 2wd/awd Bullitt cargo bike.

‘Before’ on the left is the Version 1 ‘After’ screen just above in Figure 2. On the right is Version 2

Slow Start Mode

The slow start mode – the strength of the initial punch the motor gives out when it fires up – has been turned down a notch to ‘2’ from ‘3’, which was already a low number. I have noticed the bike this is used on has a noticeable, audible clunk when the chain engages the upgraded, 36T internal ratchet mechanism of the DT Swiss 350 steel cassette body. Every time I hear that clunk is a time the hub gets beat on. Even if it was already a reduced amount, I wanted to notch it down further. This is a good thing on a heavy, often-laden cargo bike, and its probably not such a terrible thing for any ebike.

Start Degree

In Version 1 I have this set so that there needs to be just under a half rotation of the cranks before the slow-start of pedal assist engages. When all of the settings are taken in together, it typically means pedal assist doesn’t begin to be felt until the bike crosses a 5 mph speed (If I want assist earlier there is always throttle).

In Version 2, I have reduced this to a 1/6 turn of the crankarms. The idea with all of these settings put together is that assist from the rear motor starts faster – Remember, on this bike the BBSHD is supplemented by a front motor that starts almost instantly from a stop, so the BBSHD is not trying to haul a bike up from zero on its own. On such a big, heavy bike as this cargo bike, some assist from both wheels asap is a good thing. Net result is that with two motors, I can get a good result from pure pedal assist without having to resort to the battery-sucking thing that is hitting the throttle. I start pedaling and the bike sedately glides forward even if its weighing 400+ lbs.

Current Decay

This is a full 180 from Version 1, where Current Decay is set to do as little as possible, meaning the motor is the least likely as it can be to pull power as your cadence increases. Here, it is at its next-most aggressive setting. In part this is informed by the fact that there is a front hub motor (running off the same common battery) that – if faced with a sudden power drop from the rear motor – will still provide forward assist, and in practice that means it will increase wattage as its workload increases. This is part 1 of 2 of this story, with Part 2 being …

Keep Current %

The amount of assist that is retained when Current Decay pulls power back has been reduced to 30%. So the two settings together make it more likely that, as cadence increases, power will be reduced, and the amount of power that will continue to flow has further been reduced by 25% from its previous (fairly low) value.

Got all that? Here’s what the rider feels: Not much. Despite my characterization of these changes as ‘aggressive’, which they are if you just look at the numbers onscreen, reality is the result is muted. We’re using a little less power, which we don’t miss much, and that is going to give us a bump in range. At 20-25 mph, pedaling strong at 60-70 rpm cadence, the BBSHD on flat ground is eating about 200-250w on the typical Assist Level 4 and 225-275w at Level 5. Thats pretty light (power consumption will be more on a bike with just the BBSHD for a motor!)

If you want to have the motor back off when you demonstrate you don’t need it (if you did you couldn’t spin your legs and the crankarms) the Keep Current and Current Decay settings are your go-to’s to making that happen and reducing your power consumption.

The Throttle Screen

Before on the left, After on the right

There is just one change here, and its along the same lines as what I tinkered with on the Pedal Assist screen

Start Current

This is the same kind of effect as Start Current on the Pedal Assist screen, only it works when applying throttle. I have halved the initial response the throttle gives down to a 5% delivery.

What’s the actual effect of that? Well, in conjunction with the broadened Start Voltage and End Voltage already in place, setting such a low value lets me feed in a constant 50-100w to the motor. Its important to understand this is not an initial value that increases: This is the initial value that will output continuously at the lowest level of throttle engagement.

Lots of times, I want to engage throttle just a little bit to slowly navigate some delicate or narrow pathway of some kind; especially where pedaling might throw my balance off (remember I could be riding a loaded 500+ lb cargo bike). This lets me do that. It also means when I engage throttle, the thunk of the cassette body engaging itself is no longer a thunk at all.

So not only is the bike more controllable at a low level, no thunk means stuff lives longer!

I guess I won’t be selling this alloy cassette body on Ebay after all (400 miles on it and its easy to see what cogs I like to use)

Thats It?

Yup thats it. At this point in the development of what I like and dislike on a BBSHD setup, I’m down to the last of the fine-tuning.