Bafang BBS02 - fatbike - help! - noobalert -

vegarh

vegarh

100 µW
Joined
Jun 30, 2014
Messages
7
Hi all,
This is what happened:
Being a complete noob in the world of bicycle, sure, I can ride one, but all the technical stuff was completely lost on me. When receiving a offer I couldn't refuse on a Pugsley, and a bafang BBS02 500W, I went for it. Well and good. But then, In a moments clarity, I saw that the crankset and bottom bracket was a whopping 100mm :shock:
And the bafang specs says it cannot be mounted on anything over 70something. :shock: :shock:

So I'm asking: What should I do? I'd very much like to electrify my pug, I love to ride it, but it's too heavy to use on a daily commute, and me working out to make it work, well... no.

So there are some possibilities I've figured out in my brilliant, not so spec-checking mind, ranged by desirability:
- not to worry, It will fit.
- Is it possible to change the crankshaft on this motor? can I transplant my crank to it?
- Are there any aftermarket parts / something I can throw money at to remedy my problem?
- Is it adviseable to have the crankshaft extended? I get a lot of emails about extending other things, so I gather a crankshaft shouldn't be much of a challenge? What are the ramifications of doing this? How do I do this?

Any help appreciated!!

best regards
Vegar
 
Have you considered cutting the bottom bracket down to 73mm or less. Because the drive just slides into the bb cutting the threads won't matter, but you will not be able to convert it back.

You need to be really sure the pedals will clear and the chain line is correct first.


I'd probably sell the pug and use the cash to find a suitable bike for the conversion.
 
I would get a Diamant or Nakamura fatbike to modify. They are aluminum and cheap. I'm not 100% sure it can be done without the Bafang gearbox hitting the right chainstay though.
 
Hi Mushymelon and tahustvedt
Thanks for the advice, that would seem a way to go, but like you say, It will be a non reversible one. What about extending the crankshaft or using the one that's currently on the bike?
Is the crankshaft and chainwheel fixed together, or am I able to adapt another crankshaft for my use? I'm certainly no mechanic or electrician, but to me it seems there is no components or anyting vital to the motor inside between the chain wheel and the left crank, or am I mistaken?

best regards,
Vegar
 
vegarh said:
Hi Mushymelon and tahustvedt
Thanks for the advice, that would seem a way to go, but like you say, It will be a non reversible one. What about extending the crankshaft or using the one that's currently on the bike?
Is the crankshaft and chainwheel fixed together, or am I able to adapt another crankshaft for my use? I'm certainly no mechanic or electrician, but to me it seems there is no components or anyting vital to the motor inside between the chain wheel and the left crank, or am I mistaken?

best regards,
Vegar
Click to expand...

Nothings impossible but without some serious master fabrication skills and a full machine shop this is very difficult to do.
 
Hi MushyMelon,
Thanks a lot, like I said, not much of a mechanic, so please indulge a humble noob:

- Isn't it possible to fit a new crank to the existing spindle?
- Use the excisiting BB-insert
- Use the supplied chainring

My finger is now hovering over the "cancel order"-button...

thanks a lot for your patient replies :)

best regards,
Vegar
 
vegarh said:
Hi MushyMelon,
Thanks a lot, like I said, not much of a mechanic, so please indulge a humble noob:

- Isn't it possible to fit a new crank to the existing spindle?
- Use the excisiting BB-insert
- Use the supplied chainring

My finger is now hovering over the "cancel order"-button...

thanks a lot for your patient replies :)

best regards,
Vegar
Click to expand...

vegarh said:
-Isn't it possible to fit a new crank to the existing spindle?
Click to expand...

If you mean extend the existing spindle with an adapter somehow or cut and weld an extension then Yes I guess its possible but it wouldn't be reliable.

vegarh said:
- Use the excisiting BB-insert?
Click to expand...

No sorry this is how the drive is fixed into place. Its not a perfect method to begin with, it has to extend beyond the bb to secure the unit into place.

vegarh said:
- Use the supplied chainring
Click to expand...

I don't know the specs of your bike so I don't know for sure but with the two reasons above alone its a no go.

Mushy
 
ah, I see :)
Well, one in three isn't all that bad ;)
Anyhow, cancelled the order, thanks again for helping me figure this out, I'd probably end up trying on my own and end up in a poodle of tears and burnt hair - so my girlfriend thanks you too.
I stumbled across this http://california-ebike.com/fat-tire-ebikes-way/ - and has sent this guy an email to hear if he's making any headway.

thanks again, much appreciated!

best regards,
Vegar
 
Pugsley is a nice bike, and light for what it is. Why screw it up? Use a nothing-special rigid forked MTB as your donor bike. That's what the cheap Chinese crank drives were meant to fit, anyway.

Use fat tires like CST Cyclops 26 x 2.4" at low pressure like 25psi, and you'll have the next best thing to a fat bike. (Without bungling your Pug.)
 
Thanks all,
I've sent the ebay-seller a message, to find out if she's willing to sell just the kits, and is nagging Doug at California-Ebike for updates ;)

-v
 
You ever get a reply from Doug? I to have been after homm for news about BBSO2 for 100mm BB. Have a mongoose Dolomite I want to make a mid drive
 
Why not convert the Pugs, a steel frame is much easier to work on than on an aluminium frame. The left side won't be the problem, u cut it down plane the outer side with a bb Tool, thats it. You will have to use an Crankarm with more offset. On the right side u have to make shure you get the motor fit.There you need to weld or brace at the chainstays. and make a new yoke.

The BBS will just about fit a 74mm bb, so you need to get 13mm on each side. The more you get on one side, the less you need on the other.
 
tinasdude said:
You ever get a reply from Doug? I to have been after homm for news about BBSO2 for 100mm BB. Have a mongoose Dolomite I want to make a mid drive
Click to expand...

Not for the last couple of months, when they were ready to do some prototype-testing, but I guess something must have come up. I've changed strategy, and has chosen a rear-hub motor instead, from underdog bikes (www.underdogbikes.no) for the project.

=v=
 
I spoke to Doug today and personally saw the fatbike on a 10 mile shakedown ride for testing. Stay tuned as the announcement with details will likely be published in the next 3-4 days.

Subscribe to the newsletter at the following link to receive details as they are published:

http://california-ebike.com/
 
This looks nice. https://www.surface604.com/product/fat-bike-frame-aluminum-alloy-6062-matte-orange/

The bottom bracket measurements on the geometry page don't seem right compared to the photos. the rear hub spacing is weird too.
 
Well, I found a mid drive solution. Wasn't what I was originally looking for, but for the price, couldn't turn it down. http://electricbikereport.com/biktrix-juggernaut-fat-electric-bike-with-mid-drive-video-pics/
 
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