Teaker68
10 W
Noobey here, looking to see if anybody has built a Fat Tire Bike utililizing a Bafang Mid Drive? I know they can work with two different bottom brackets and cranks but not something this wide that I know of.
Converting Fat Tire Bike With Bafang Mid Drive BBS02
- Thread starter Teaker68
- Start date
Drunkskunk
100 GW
Sadly, it won't work as is. Fattys use a 100mm BB.
If you can fabricate parts, you might be able to make this work, cutting the BB so the motor runs offset to the right, then using an extended left crank arm to get proper pedal placement and clearance. It would make a hell of a great bike
If you can fabricate parts, you might be able to make this work, cutting the BB so the motor runs offset to the right, then using an extended left crank arm to get proper pedal placement and clearance. It would make a hell of a great bike
Teaker68
10 W
Thanks, I appreciate wish I had the tools and know how to do it. Just checked out your link to build too funny!!! Awesome build and bike. You have some talent there !!!
Well, it's been just about a year since this discussion was active, but the idea remains as good as it ever was. Recently, I acquired a Walgoose Dolomite 7 speed Fat Bike. The BB is 100m. In American it is 1.25" wider than the 68mm that a Bafang BBS02 is designed for. I have calculated I will have to cut 1/2 off the right side and 3/4 off the left side of the BB. I have offset crank arms to miss the chain stays and will have to use an offset chain ring to keep the chain line from hitting the tire. Don't think 5inchers will work with this design. I'll keep you posted and put up pix as this project develops. 
motomech
10 MW
Eco\speed makes a Fat Bike mid-drive. Didn't see a price, but I'm sure it's not cheap. Might give you some ideas.
http://fat-bike.com/2014/03/press-release-ecospeedfatback-electric-fat-bike-announced/
http://fat-bike.com/2014/03/press-release-ecospeedfatback-electric-fat-bike-announced/
Drunkskunk
100 GW
tinasdude
100 W
California e-bike is supposed to be working on a solution :lol:
tinasdude
100 W
AFT mid drive makes one that will fit 100mm BB. I want the BBSO2 FOR MY DOLOMITE As well. It is stealthy. AFT not so stealthy. Chain drive, but next best solution I can find thus far without taking out a 2nd mortgage.
Ykick
1 GW
Bafang might wanna look into offering a 100mm BB system? There's a TON of interest and I would gladly pay additional $100-$200 for that.
Ypedal
100 TW
i'd get on that list as well... my Norco Bigfoot currently has a front geared hub motor but i'd love more power..
Drunkskunk
100 GW
I'd 3rd that list. That just sounds like way too much fun.
has anyone taken the BB01 apart yet? I'd love to see what the crank spindle looks like. maybe a custom one could be built?
has anyone taken the BB01 apart yet? I'd love to see what the crank spindle looks like. maybe a custom one could be built?
spinningmagnets
100 TW
lectriccycles is a US dealer for BBS02's, and their store carries a fat bike with the BBS02 already installed (no suspension, $3500). I don't know what brand of frame it uses, or how wide the BB is. I suspect it has a 100mm BB, and lectriccyles is locally making a custom bracket to mate the two. I think he was smart to be an early adopter of both the BBS02 and E-fatbikes.
http://lectriccycles.com/products/chubby-750
http://lectriccycles.com/products/chubby-750
Ykick
1 GW
If there was ever a "match made in heaven" I believe BB drive + Fat Bike combination would be as close as it comes. Most people love those fat bikes until they pedal 'em unassisted. But the ride and slow, stable off-road capability make them an emerging favorite in the bicycle world.
C'mon Bafang, do we need to start a petition thread? LOL....
C'mon Bafang, do we need to start a petition thread? LOL....
Drunkskunk
100 GW
spinningmagnets said:
I saw that, but it looks like they used a standard frame with a 135mm rear spacing and a Nuvinci. The chain clearance past the tire looks non existent. I'd bet the crank is a standard 68mm as well, which means the crank arms would just barely clear the frame.
I think a set of wide arm cranks would go a long way to making this idea work. I couldn't find any that weren't part of a kit, but something like these maybe: http://www.gasbike.net/Wide-Pedal-Crank-Kit.html
Stick those on the BBS02, fir it to a 68mm crank, and still be able to run a fat tire. It would still need a stand off to set the crank's gear over a little bit, but this seems like a workable solution.
If I can find a steel frame Fatbike for a reasonable price, I may try this.
tahustvedt
10 kW
The q-factor on the BBS is extremely large, so if the frame is designed with a 68 mm bottom bracket and the rear wheel a few cm farther aft so that the chainstays will clear the BBS then it'll probably work.
tinasdude
100 W
I e-mailed California e-bikes. Receive a response yesterday. A few weeks away from a longer axled BBSO2 for fattys! Indeed great info. Wish they would add some cooling fins.
Russell Biggs
1 µW
- Joined
- Aug 1, 2014
- Messages
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I am going to try to build this up on my Surly Pugsly. I have the wider cranks and will let you know.
tahustvedt
10 kW
I just prepared my fatbike for BBS01 conversion in preparation for winter. I used a hammer and banged the right aluminum chainstay concave where the BBS need room, and milled down the right side of the bottom bracket by 10 mm, and the left by 12,5 mm. My frame is a Diamant Mammut Mk1, and is very beefy and has a cross beam between the chainstays so I'm not worried about the strength.
The BBS now fits well, but needs a new left crank arm with more offset than the very flat stock crank arm. Shouldn't be a problem. I test fittet my BBS the other day successfully and will finish the conversion nerarer to winter. Here's a picture I took today of the first test ride after the modification. I made adapters to keep using the 100mm crank until I need the motor. I painted the frame and did the bottom bracket mod two days ago.
The BBS now fits well, but needs a new left crank arm with more offset than the very flat stock crank arm. Shouldn't be a problem. I test fittet my BBS the other day successfully and will finish the conversion nerarer to winter. Here's a picture I took today of the first test ride after the modification. I made adapters to keep using the 100mm crank until I need the motor. I painted the frame and did the bottom bracket mod two days ago.
Attachments
MikeFairbanks
100 kW
Why mid-drives? Wouldn't it be easier to just add a hub motor and rebuild the front or rear wheel?
tahustvedt
10 kW
MikeFairbanks said:
I initially wanted a hub motor for the front wheen to give me more traction in deep snow, but decided against it because of the torque required to drive a 29" diameter wheel at low speed with high efficiency. Are there any 250 W hub motors that work efficiently at 100 rpm? With the current tires my wheels are 735-740 mm diameter, which is about 29".
tinasdude
100 W
Just spoke to Doug at california e-bikes. The BBSO2 kits for fat bikes will be available for sale after he returns from interbike
docnjoj
1 GW
XiongDa 2 speed might fill the bill.tahustvedt said:
otherDoc
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