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…
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:
For 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.
EDITOR NOTE: Luna Cycles provides spacer kits with every BBSHD Kit now so custom fabrication like this is not needed.
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.
Bag and battery packaging, and wiring
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:
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.
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/
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/
Total Spent $3307.