Fatbike with BBS01

I installed my BBS01 250 W 360 V motor on my Diamant Mammut (norwegian brand) fatbike today. I milled down both sides of the bottom bracket, and hammered the right chainstay flatter to make room for the motor. It fits well now and with a mtb left crank arm which has more offset, the pedals are better centered than a stock BBS install. There is not enough room to install the motor bracket or locknut, but I don't care as the motor won't be banged into anything. This will be my commuter bike here during the rough northern norwegian winters. I will use 12 Ah 10S lipos to power it. I rode today with a 6 Ah pack and it was great. The 46t chainwheel is silly on a bike like this though, so I'm going to CNC mill a 32t one. I'm not using any brake sensors. The speed sensor is mounted on the right chainstay because the rear wheel is laced offset.

The bicycle has 100mm bottom bracket width standard?
Assuming the widest width the BBS systems accomodates is 83mm you had a bit to take off on each side? Can you elaborate more on this process so folks are in the know how to modify their existing bikes with similar sized bottom brackets

Yes 100 mm.

I took the bike apart and laid it in my CNC router and milled down 12 mm on each side of the bottom bracket. Then I pounded the right chainstay so that it bulged inwards. Before installing the BBS I faced the bottom bracket using a bottom bracket facing/threading tool.

It could be done without machining equipmentby cutting the bottom bracket with a dremel or something on each side, and then facing the surfaces with a bottom bracket facing tool. Should do the trick.

The weight is a smidge under 22 kg (48.5 lbs) with the 12 Ah lipo.

Don't you need some way to support the motor from moving towards the ground?

Electric Junk said:

Don't you need some way to support the motor from moving towards the ground?

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Trust me the motor wants to move up not down. I have 3 Baffang mid drives and the motor moving around is not a problem. Your bottom bracket would have to be super loose for it to move around.

Yeah the motor will push itself really hard against the downtube. On my other bike I used a furniture floor protection rubber pad thingy between the housing and frame, and the motor had pressed it completely flat.

Omitting the motor support bracket is probably not a good idea for trail riding, but for snow commuting it should't pose any problems.

I made a new chainring today. 32t that bolts directly to the output. Then I went on a 28.6 km ride to test the range. I used 199.5 Wh / 5.311 Ah and pulled 569.9 W peak. The battery is 12 Ah 37 V lipo and the motor is a regular 250 W BBS01. With "keep current" set to 60.

I don't take orders. I'm way to busy.

Found a fatbike frame which should fit: https://www.surface604.com/product/fat-bike-frame-aluminum-alloy-6062-matte-orange/