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Editor note: On our new forum there is an entire section for members to document their BBSHD builds and show what bike they started with what parts they bought and how they assembled them into a working electric bike. Here is a build report taken direct from user “JP LABS” on the electricbike.com forum. Its great build reports such as this that will pave the way to new builders on how to build an awesome bike for not much cash. Come join our forum here.This is my first build, an e-Fatbike. I installed a BBSHD and 20-Ah Panasonic PF triangle pack, both from Luna Cycles, onto a Motobecane Sturgis Bullet. I’ll try to provide enough details and photos to make the process clear.
This bike is a blast to ride. I put a 30T Mighty Mini sprocket on it from the start. I only have 5 miles on it, at sunset tonight, after finishing up the build. I was in PAS mode 1 most of the time – it is the highest PAS setting I can keep up with, pedaling for real to help. I was not disappointed by how quiet and powerful this drive is, and I’m nowhere maxing it out yet. The tire knobs drown out the drive noise, which itself is very smooth and pleasant sounding. Sweet!
Frame size is 17.5″, Medium. I’m 6’1, but I wanted my 5’4″ daughter and wife to be able to ride it once in a while. It fits me fine, and they can stand over the frame. Barely. I cut one inch off the seat tube so it can go low enough for them. I set it to the full recommended extension, and it fits me well. Inseam 36″.
I chose that model bike in particular because it comes with a ($600+) Bluto fork and has a relatively open frame triangle for battery clearance. It also comes with nice components such as Mulefut tubless-ready clincher wheels and Snowshoe tires.
I chose the 120 mm BBSHD kit. I wanted the crank arms centered on the frame. The right side pedal clearance is set by the motor, and nearly all the shimming was on the left side, so a 100 or 110 mm kit would have resulted in the same pedal spacing anyway, if I added a offset LH crank arm to get the pedal spacing symmetrical. You need to cut off about 5mm from the front derailer mount on the frame to center the install (motor just touching rear triangle) and that gave me the best chainline. That 120mm kit fit very nicely, with only shimming, once the frame was slightly modified. More on that, below…
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OK, on to the actual build.
First of all, removing the stock crank arms was not easy! I bought a puller tool that would thread into the arm, but the crank is hollow, so there was nothing to push on with the puller’s center bolt. I wound up heating the right crank arm to maybe 200F, and then pounding on a steel rod inserted through the crank from the left, hitting the puller tool hard enough to drive the right arm off. LBS said it should be ‘self extracting, no tool required. Well, I don’t agree. My stock bearings would probably click if I tried to use them again. Not recommended, but I didn’t want to wait a day for the shop to do it.
This tool fits the outer nuts on the stock crankset, but only after cutting off the ‘rear cassette removal’ half of the tool. With that 2nd tool still attached, it didn’t fit over the splines on the crank. Not hard to cut with a bandsaw, but I’d advise buying the same socket style WITHOUT the bonus tool on the back of it:
https://smile.amazon.com/gp/product/…?ie=UTF8&psc=1For the inner nut, I used a Fox spring perch wrench from a snowmobile/dirtbike sized shock. I needed a 12″ total length handle to get that one off. Not bad.
OK, on to fitting the drive unit.Here’s how it lined up before trimming the front derailer mounting bosses. As mentioned above, with this frame, you need to trim the bosses. I cut the long boss off flush with the short one, and then chamfered the short one, in order to get the required clearance so I could set the gap between the motor and frame to ‘just touching’:
Once the frame was trimmed, I needed a small (0.1″) spacer on the RH (drive) side, so that the motor wouldn’t be side loaded into the frame.
EDITOR NOTE: Luna Cycles provides spacer kits with every BBSHD Kit now so custom fabrication like this is not needed.
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The downtube on the Sturgis is flattened on the bottom, and the back of the bolt boss on the BBSHD hits the downtube, leading to a rather low mounting position, with the BBSHD rotated further down than I liked. So I ground away some of that boss to gain more ground clearance. I did not hit threads or motor interior – this was extra metal, not apparently needed. I went very slowly, in case I broke through, knowing a dab of metal epoxy could repair a small hole well enough, but not a big one.
I put a piece of innertube between this boss and the frame, then allowed the whole motor to rotate while I tightened the bottom bracket nuts. So, it is pretty tightly held to the frame. I used adhesive to attach the rubber pad to the motor, so that if the motor ever comes loose, it won’t damage the frame when it swings back up under torque.
Finally, notice the little dents around the crank hole on that motor bracket? On the other side are bumps which help keep the bracket from rotating. Make sure you put the bumps towards the bike frame when you put the bracket on:
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So, how’s the chainline? Not bad! Centered, at least. But there is a fairly big zigzag at the extremes. Tire clearance is real good to the chain. I have not had any trouble with shifting, after re-adjusting the shifter cable length. I have not applied full power in top gear at high speed yet, though, either. I have floored it in low gear, no issue.
The mighty mini 30T. There is room for a bigger chainwheel to clear the frame, without making the chainline worse. I know there are a couple of 42T chainrings out there, like the Luna Eclipse. But they move the chain inboard. Perhaps too much, as this lines up pretty well in #5 & #6 gears (10 speeds). I think I’d like to try to put a 36T on there for slightly higher gearing. But I can’t find an adapter to fit the BBSHD for standard chainrings
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This Luna Cycles triangle bag is a little big for the frame, but squashed to fit nicely. I was going to add foam around the perimeter, but realized I wanted to carry a spare tube, too. Spare tube=frame padding! Once I get a rear rack and bag, I’ll put the pump there, and add some foam between the pack and the inner tube, as well. This is a well made bag. Tough, good shape, straight seams, and a water seal on the zipper. Be sure to remove the bolts from the water bottle bosses on the seat tube and down tube, or they will create concentrated impact points against the inner tube and pack. Or use thicker, firm padding. I would NOT recommend just using the battery bag without extra padding, while also leaving the bolts in the frame. I think the pack could be damaged. The bag does have some padding, but why make it’s job harder than you need to?
Bike pump will fit above, snugging everything up nicely. Firm fit, not crushing. Luna Wattmeter fits alongside with no problem.
This is an XT60 splitter I made for connecting the Luna 15W headlight and taillight to the charge port of the pack. I added a 1A fuse, in case of wire damage. I used a 1-1/4″ (30mm) ACG fuse and holder. These are only rated for 32V, but I test blew one and it popped nicely, with no arcing. So I think that will work fine.
Rear wiring entrance. The power leads from the motor reached the wire port ok. It would be nice to have a wire entry at the bottom of the pack for the controller harness. It was not long enough to go through the upper wire port while also leaving enough slack to not be damaged if the handlebars got reversed, so I ran it into the zipper gap.
I will probably add a wire entry port at the very bottom of the pack to allow hiding the motor wiring entirely inside the bag, but I’m not sure how to do that without compromising the strength of the bag:
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Only one thing surprised me about the BBSHD design. When pedaling with the motor off, the pedals seem to spin the gears inside the drive unit, which adds a noticeable amount of drag. It does not spin the motor, just the gears. I expected the pedals to be able to turn without spinning any of the internal drive parts, more like a regular bottom bracket. I’m not certain it is supposed to work that way, but I suspect it is by design. I haven’t seen anybody else mention it, though. I didn’t disassemble the motor to confirm this 100%, but I can feel the drag, and it feels like gears meshing, that kind of vibration. If it’s not the gears, then the clutch is rather draggy. It’s not enough to be a problem when pedaling only, probably not noticeable; I just found it interesting.
Turning the rear wheel backwards DOES spin the motor, with significantly more drag, but I don’t plan on riding backwards very much, so no big deal there. But it let me confirm I wasn’t feeling motor drag with the pedals.
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Parts List:
I really love this combination of bike, drive, battery, triangle bag, and lights. Here are links to the actual components and sources I used, except for the XC60 connectors for which I provided a better option in the link:
Donor Bike: http://www.bikesdirect.com/products/…et-mulefut.htm
Motor Kit: http://lunacycle.com/motors/mid-driv…-kit-in-stock/
Mighty Mini 30T chainring: http://lunacycle.com/inventory-contr…n-ring-silver/
Battery: http://lunacycle.com/batteries/packs…650-21ah-pack/
Charger: http://lunacycle.com/batteries/charg…ebike-charger/
Headlight: http://lunacycle.com/black-friday/lu…t-extra-power/
Tail light: http://lunacycle.com/black-friday/rear-light/
Watt Meter: http://lunacycle.com/batteries/guage…le-watt-meter/
Brake Sensor for hydraulic lever: http://www.empoweredcycles.com/colle…r-brake-switch
XT90-S connectors for BBSD Power Leads: http://lunacycle.com/batteries/conne…connector-set/
XT60 connectors for lights – these are better than what I bought and used but I hadn’t seen them at the time: http://lunacycle.com/batteries/conne…nector-5-sets/
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Total Spent $3307.
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Doug Tally
( March 12, 2016 )
Hi Eric, I read other articles you authored and I’m pretty sure one of them was a review of the Sondors Fat Bike. How much different is this build from the Sondors Fat bike?
I’m interested in putting an electric hub on the front of the bike I ride year round in Chicago. I’d love to ride in the snow but it’s not possible without front wheel drive pulling and my self-powering the rear.. Then I remind myself, this is way out of my skill set. Is it feasible to install an electric front hub to my existing bike and I power the back end?
Maybe I’d be better off putting $50 down on the Sondors Fat Bike and look for help to install an electric front hub for the 2 wheel drive I want. What happens if the electric motor and battery get wet or even submerged in fresh water… what then? Submerged would be secured to my packraft and get turned over, not worried about losing it, just it being submerged.
Thanks,
Doug
Electric Bike
( March 14, 2016 )
Hi Doug,
of course this bike is better and more powerful than the Sondors but the price is 3x more expensive.
If all you need is a little bit of power you cant go wrong with the sondors.
IF you need big power the BBSHD is the way to go.
Installing a front hub and a battery will give you about the same performance as as sondors at almost the same price.
v3ngence
( March 13, 2016 )
Nice build, should be a blast! Just keep an eye on that Luna triangle bag, not bad for the price, but mine lasted less than 10 rides before the zipper head cracked and broke. Upgraded to a Revelate bag, more padding and the zipper is insanely strong, at least 5x larger!
copajoe
( August 22, 2016 )
my zipper broke when installing the battery. not one time used! I guess I will look into the Revelate bag….
Doug Tally
( March 14, 2016 )
Eric, why are nearly all e-bike designs rear wheel powered? I need front wheel e-drive and I’ll power the back. What am I missing about the rear power design?
Electric Bike
( March 14, 2016 )
Front wheel drive is fine but many people are afraid of it.
You need to make sure you have good torque arms or a steel fork…but if you are careful there is no problem with it especially at lower power levels.
I prefer front wheel hub motor bikes myself to rear motors…that way i have all wheel drive with me pedalling the back 🙂
Doug Tally
( March 15, 2016 )
Eric, I didn’t know that about front wheel drive. However, my experience without it on snow, in dirt ruts, and in sand mixtures are lessons learned. I’ve been trying to envison a hub design for self-power to the front, but an e-hub is the only way I know for 2WD.
What fat bike would you use to install a front ehub?
Thanks again,
Doug
Electric Bike
( March 15, 2016 )
Any fat bike with a rigid fork is fine….steel is preffered….and be sure to use torque arms to stay safe.
kristian
( August 31, 2016 )
Hey, thank you for the 411. Im going to att3mpt same build sturgis buplet w bbshd. What tool did you use to cut down the front bosses? Im new to building things but i want to do this and b3 able to service my own ride when it needs it. Thanks again fpr your help.
Sturgis bullet xl, bbshd Luna cycle, 52v 13.5 ah luna cycle, lekkie bling 42t, nuvinci 360. Cycle analyst v3, tektro front brakes, luna cycle mudguards (stromer),
Primary use daily commuter 9.5miles each way in NYC.
peterewills
( August 29, 2017 )
Any chance of reposting with updated image links? I’m looking at converting my Sturgis and am very interested. I know Imgur hosts for free, if you’re looking for somewhere to host.
Dakota Callahan
( April 8, 2018 )
I am looking to use the sturgis bullet for this build. Is there anyway you could get the pictures updated so we can see them?