My first Bullitt – the Lizzard King – was the basis for this bike build and written up extensively here. This bike is essentially a v2.0 of the same bike. There is much background detail left out of this current discussion (like drama-free AWD) since it was covered the first time around.
Before I get started, lets address why I need two Bullitts. When I built my first one, it was a bucket-list item I expected to last me forever… and its still going strong. But, here’s the thing: I split my time between two locations.
I work in Fresno California, where the land is all table-flat, and my job has for the last several years required me to essentially move there and set up a second residence. My actual home is in Pacific Grove, California… which has totally different terrain. Where Fresno is roasting hot in the summer and flat as a table, ‘PG’ is smack on the Pacific Ocean seashore, is only flat at the shoreline and has plenty of low but steep hills. I live at the top of one, in fact.
Recently I was finally able to start living at home again. My Surly Big Fat Dummy provided cargo bike duties, but I found something I didn’t expect: Having had a frontloader for a couple of years, now I knew what I was missing. I didn’t want to put up with the quirks of a longtail. I ended up describing the differences in detail. I found I was actually resenting the ride limitations, and putting off rides as a result.
Sneaking into Laguna Seca Raceway while it was closed for construction – I had the whole complex to myself. The Surly Big Fat Dummy was a joy to ride that day.
Screw that. Cycling is an integral part of my life. Its time to
Build Another Bullitt
As part of the build planning process, I needed to do a Build Sheet. Click the image below to go to the actual build sheet complete with links to almost every part in the build. I won’t discuss every bit and piece in this short series, but this list contains pretty much every part.
So… how do I organize this writeup? This bike is at its core just an improved version of the one I already built and documented. There’s no point in doing that all over again, but at the same time its hard not to if I want to avoid making the reader bounce back and forth from one build description to another.
Lets just start at the back of the bike and work our way to the front. I’ll go into details where I think they are worthwhile, and be brief when I think I am on well-covered ground.
This is a fairly common Axiom Streamliner DLX. Its got dropout extensions that move it well back for heel clearance, and a 50 kg weight limit. It is the identical rack I used on my first Bullitt, but oddly, this time the rack fit perfectly with none of the mods needed to get its dropout extension to fit. Apparently Larry Vs Harry have moved the threaded boss on the dropouts down by just a bit versus the ones they sold two years ago.
A standard-issue Axiom Streamliner rack with an extra-beefy front mounting bracket. No idea if this increases its capacity but factory stock its rated for a lot of weight already.
I also used a beefier center stay mount from one of my Axiom Fatliner racks and created a stronger-than-stock solution.
Similar to the ‘bobtail’ deck I made for the Lizzard King, this rack has a ‘deck’ made up of two components. One is a long strip of aluminum flat bar, 2″ wide and 1/16″ thick (sorry for the Imperialist units of measure but thats how its sold here). This flat bar is drilled and bolted to the front of the rack using existing holes. Holes drilled at the rear simply use a zip tie to attach it to the back of the rack. As previously, this thin aluminum bar is part of the rear fender solution.
You’ll notice the deck bar is longer than the rack, and bent up in the back. I did these two bends by sticking the straight alloy strip in a big steel door and frame, and putting my weight behind it. With that bend in place, mounted on the rack, the deck now has a sort of kicktail… like on a skateboard. It doesn’t serve the same purpose though: The extended bit of deck catches water spray coming up off the tire. So its part of the ‘fender’.
The deck is extended in a second bend that goes up to vertical. In the back of this portion, I stuck some prismatic red tape – the same type as is used in municipal street signs – for a big passive reflector. Additionally, on the front – because why not? – I mounted a square of yellow prismatic tape for forward-ish reflectivity (my local laws prohibit the use of red, facing forward).
Lastly, at the top of the kicktail, you can see a short black strip. This is a narrow length of thick rubber mastic tape. It extends well past the deck’s edge and folds over onto itself, so it becomes an extended rubber bumper. I have learned from doing kicktails like this in the past that if you don’t cover the trailing edge in rubber, sooner or later you cover it in blood (even if you file the edges down).
Last time, it was a ‘bobtail’. Bent differently so it was a smooth curve. Executed a little differently this time to give me a tighter radius bend and a perfectly vertical section this time for the rear reflector.
The Plastic Sheet
The second component to the rack deck is a bit of thin flexible sheet plastic. It has been cut to fully cover the rack, and then slipped under the aluminum bar. Holes matching the top deck have been drilled thru it and as such it is affixed tightly and permanently to the rack. To mount a pannier, you only have to lift up the very thin plastic and attach the pannier’s hooks as usual.
The use of a narrow strip of aluminum, coupled to a flexible sheet of plastic that covers what the alloy does not, gives me full rack deck coverage while maintaining my ability to easily attach a pannier. Why bother? Because this is a part of the rear fender-that-is-not-a-fender coverage.,
Rear Mud Guard
The closest thing to an actual fender is a really big mud guard. It is a Mucky Nutz Fat Face Fender XL (They sell white ones on clearance dirt cheap). It is a front fat bike fender, put on the back wheel, and reversed. Then to extend it in back I added some white gorilla tape. It is bolted to the frame in front using the fender bolt and boss that LvH put there. This bolt pulls the mud guard forward to clear the 2.0″ Schwalbe Marathon Plus Tour tire.
Working together, the rack, rack deck and mud guard provide full fender protection without the use of a fender.
A little matching white extra wide gorilla tape, judiciously applied, extends the mud guard up to the rack deck – no water makes it onto the rider.
Same as I do on every one of my bikes: I am using 203mm wide, 2.3mm thick Tektro Type 17 rotors and Magura MT5e 4-piston calipers front and rear. The front brake cutoff is connected to the front motor and the rear cutoff is connected to the mid drive. It is not possible to cross-connect the cutoffs to the dissimilar motor controllers so either one cuts off both motors.
Rear Wheel (and Drivetrain)
The Lizzard King, my original Bullitt, has an 11-speed drivetrain and a 52T (!) front chainring, feeding an 11-42T rear cluster. I only use the middle three or four gears to maintain good chain alignment and high pedaling cadence.
This time I need to negotiate steep hills whose slopes vary, often on the same climb. So a big rear cluster is a given, strength is paramount and I need more usable gears to work with the varying terrain.
The Bullitt has short stays in the back. A BBSHD moves chainline outboard. So no matter what chainline angle will be a challenge. Its going to be tough to use the smallest and biggest cogs on the cassette.
Done… Then Re-Done
Drivetrain Plan A
My first setup was a 9-speed system. I used the Box 2 Extra Wide derailleur, an ebike-friendly Box 1 single-shifter, and its matching Box 2 12-50T cassette cluster. I have used this hardware in the past. It is a premium solution that is not the cheapest, but a lot less expensive than the upper tiers of the other Big S brands.
Pics or it didn’t happen: The Box derailleur can reach the 50T cog. The 12T little one can be reached too. But both of them are too far over inboard or outboard to be used meaningfully.
I labeled the Box Components drivetrain as Plan A. We’ll look at Plan B, and why there is a Plan B, further on.
Next in the drivetrain, there’s the front chainring. I have used the 40T Lekkie chainring and the smaller-than-stock motor cover it requires on my Apostate, and knew it worked well. The 40T ring also has a lot of inboard offset, which you need on the LvH frame.
The Lekkie ‘Pro’ 40T chainring, which only fits over top of the Lekkie motor cover. Note the smaller chainring teeth that are 10-12 speed compatible. No 9s.
But I need as much offset as I can get. Lekkie makes a ‘Pro’ line of chainrings, and they have an additional 2mm of offset. I wanted that extra 2mm as I will ride this bike on the bigger, inner cogs. Complicating things: the Pro rings are not 9-speed compatible. They have a different tooth profile meant for 10-12s systems.
I got around this by using a SRAM EX1 mid drive chain, which is compatible with 8, 9 and 10s systems, so I’m still good.
By using the Pro chainring I gain 2mm. If I perform an optional modification to the Bafang motor casing, I gain another 2mm. With those two mods I moved the chainring a full 4mm inboard towards the seat tube.
Shave off some of the BBSHD motor housing, just behind the Lekkie motor cover. This lets you do without a 2mm spacer to gain that much more offset. Done in about 15 minutes with a hand file.
Drivetrain Plan B
After I built the bike, and ran it for a couple of hundred miles, I was not happy with the Box Components drivetrain. The matched set of components are every bit the butter-smooth, high quality system I expected them to be. However, chainline considerations kept me from using three of the gears on the 9-speed cluster. Since I am a pedaler and not a throttler, I still benefit from lots of gears despite the electric assist. A 6-speed leaves room for improvement. I was missing my 11-speed on my other Bullitt.
Contemplating this, I had – sitting on a shelf unused – a Microshift Advent X 10-speed drivetrain looking for a home. It looked like a solid alternative that might give me a couple more gears, with no meaningful penalties. Here’s a comparison I put together while I decided what to do:
My real comparison was between the top two choices, but I also threw in the Microshift Advent 9-speed steel cluster on the Box 2 derailleur (I use that on my Apostate) just to see how it lined up.
In the chart above, the red cogs are too skewed to use. The yellow are livable if I must and the green are good to go. This chart told me
- If I am limiting myself to my 3rd-from-the-top cog to be absolutely safe, both clusters are giving me the same 34-tooth big cog.
- The next cogs down on the Advent X give me as-good or better higher gearing.
- I get more gears to work with – two more – on the Advent X.
- I never want to use the smallest cog anyway on any mid drive build, so I don’t care about the little one on either choice.
- It looks like the Advent X is going to give me smaller cogs for when the ground is flat.
The saying goes that ‘Steel is real’ when it comes to tough bike frames. The same is also true of a cassette cluster that gets flogged by a mid drive motor.
Here are some known issues that aren’t on the chart:
- I’m going up steep hills with 100+ lbs of load on the bike, not counting my own self and my extra heavy locks (2 meters of boron steel noose chain and two motorcycle U locks). This puts severe strain on the drivetrain and demands a conservative limit on how skewed I run the chainline.
- The Microshift Advent X cassette is ideal as beefed-up mid-drive-friendly clusters go. It has all steel cogs and is permanently pinned together on all but the smallest cogs, so force is distributed across the entire cassette body rather than having one cog dig in at a time.
- My handlebar layout made space a premium. The Box One shifter surprised me: Shifting often required the full throw of the shift lever, so it needed more space on the bars. SRAM shifters only require a very short throw. So there was something else I was missing.
Chainline on the inside, middle and outside. Even though I can get to the 48T cog, chainline is too skewed for a hi torque uphill slog.
with 250 miles on the odometer, I changed the drivetrain for the Advent X. It has worked beautifully. Shifting has been great all across the gear range. When I need a new cluster, I’ll be replacing a US$40 part.
I also followed a tip from a Youtuber and put an 11-speed chain on this 10-speed system. 11s chains have identical inner dimensions to 10s. They are just a hair narrower on the outside. Using an 11s, you gain an absolutely silent drivetrain. I didn’t realize how loud my SRAM chain was until I switched and… blessed, complete silence. It runs as quietly as a belt.
I used a Wipperman Connex 11se ebike chain on sale at JensonUSA for a whopping US$23.94 rather than the usual US$106.95. After seeing how well it performed, you can bet I bought enough spares at that price to last me for the foreseeable future.
On the innermost cog, which we’ve already established is not usable, the limitations of a mid-length cage versus the Box 2’s extra-long cage are apparent. Its a smaller cog than the Box 50T, but the derailleur is pulled far forward thanks to its lesser ability to wrap chain. Right picture: Three cogs down – the one I consider the max on really steep, loaded climbs – the derailleur is in a happy place.
I still love the Box Components drivetrain. I’ll move the 12-50T cluster to the Apostate, which can use the bigger cogs. The derailleur and shifter… I’ll find a use for them someday.
Drivetrain Plan C
Update – July 18 2023: Figuring out the ideal drivetrain for this bike reminds me of why I wrote Musical Chainrings back in 2020. I got great results from the Microshift Advent X rear drivetrain and Connex chain, but I wanted to do better. The Plan B cog diagram with the 40T Lekkie chainring shows the 40T rear cog in yellow. That is because it skipped occasionally under severe load (steep hill, loaded with cargo). To get 100% reliability I needed to be down on the 34T ring.
The Lekkie 40T ring, in conjunction with the fancy motor cover and the filing mod I described above in Plan A, delivers 22.25mm of inboard offset. The Luna Eclipse on the other hand delivers 24.8mm. An inboard shift of just over 2.5mm. I expected that to do me no favors on my lowest 11T chainring… but since this bike is a hill climber, I’m OK with that. Plus, since I was going up to 42T from 40T on the front ring, I expected to get some of that lost speed potential back on the next cog up.
After and Before: Plan C at top, Plan B at bottom.
What ended up happening was a better result than I expected, and for a reason that is obvious now, after the fact. Sure, the increased couple of millimeters helped with my big cogs in back some, but the real benefit came from the different tooth profile.
Lekkie Pro rings have different teeth than other chainrings in their product line. The Pros are 10-12S compatible, rather than 9-11. The Pro teeth are noticeably smaller, and it turns out that is the real problem causing the skipping. The smaller teeth simply are not well suited to cargo bike duty in steep hills.
By contrast, Luna Cycle’s Eclipse uses what they call a ‘wicked’ tooth profile designed to aggressively prevent chain drops under severe circumstances. It turns out the ring creates a bit of chain noise, but otherwise it works noticeably better across the board. Chain engagement is largely skip-free at the extremes of low and high gears, and even the 11T cog I expected to be shut out of is usable on flat ground for unloaded speed runs.
Those chainring teeth sticking up and out past the height of the chain… maybe they are kinda wicked at that.
The increase to 42T from 40T has not been a problem since I can now get to much bigger cogs in the back. The extra gearing has actually proven to be a benefit on flat stretches where I’m not loaded and want to go a little faster.
Plan C has been on for a few hundred miles and I expect this is finally the setup I’ll stick with.
Build a Wheel
The final drivetrain item is the construction of the rear wheel. I originally wanted to duplicate what I did on the Lizzard King, but the almost-indestructible SunRingle MTX39 rim was unavailable. The DT Swiss FR560 downhill rim is at least as strong, half the weight and twice the price. I’ve used them before and they are awesome so thats where I went.
I stuck with my usual DT Swiss 350 Classic ratchet engagement rear hub, with added ebike/tandem 24pt ratchet and steel cassette body upgrades. I’d have preferred a DT 350 Hybrid that includes these upgrades on a beefier hub, but just like the MTX39’s, they were nowhere to be found at the time. Spokes are Sapim Strongs with brass nipples.
The rear wheel is shod with a Schwalbe Marathon Plus Tour, which has a near-knobby articulated tread. Our local bike paths get covered in sand whenever the wind blows, which is a lot here.
This is a paved path about 15 feet wide and the main local urban cycling thoroughfare. It was buried in sand the day before when the wind kicked up. I need knobby tires year-round here.
The next step from the back of the bike forward is mid drive motor installation and (drumroll) configuration. That is a big enough topic to make this a good time to wrap up, take a breather and continue the story in the next post.