Bafang Bearing Question

John L.

Member
I've had my 500W 8-Fun BBS-02 on my Surly Ogre for almost a year, and I have had no issues ... until now. Within the last week or so, I've noticed a little "creak" coming from the front crank every time I pedal under load. It's not super loud, but it's noticeable. It's not the chain, which is fairly new and properly lubed. The motor itself is secure. It doesn't move when I apply side-to-side pressure, but when I grab the crank arms and try to move them side-to-side they move very slightly.

Has anyone else had this issue with a Bafang BBS-02? Is this just a matter of tightening the crank arms (I hope), or a more serious issue with a bearing in the motor?
 

flymeaway

Well-Known Member
I've noticed a little "creak"

OK...I have had the same "creak" on my Neo Carbon and on 2 of my Bafang mid-drive conversions. In all three cases it was a loose screw holding the right side crank arm to the BB axle. You can confirm the problem by trying to tighten the fasteners holding on the crank arms. In my case even tightening them as much as I could didn't solve the issue, they would eventually loosen up. So I used Loctite #263 to solve the problem. No more creaking loose crank arms. Just be ware, if you use Loctite #263 (red) you may have to heat up the fastener to unscrew it. #263 is semi-permanent and generally can only be removed if the material is heated.

Court J.
 

J.R.

Well-Known Member
Most manufactures and bike techs say, don't use threadlocker compounds (Loctite blue 242 or red 271) on crank arm bolts, many riders say, do!

http://www.pinkbike.com/news/Tech-Tuesday-Thread-locker-Basics-2011.html

https://www.google.com/webhp?source...blue+loctite+be+used+on+bike+crank+arms+bolts

I've always gotten by with anti-seize (Loctite 37539) and a torque wrench. I would try the simple things first, like tightening them to mfg specs and eliminating all other possible causes. If I had a constant problem with the crank arm pinch bolts coming loose, I would then try the blue 242.
 

Kado!

New Member
I've had my 500W 8-Fun BBS-02 on my Surly Ogre for almost a year, and I have had no issues ... until now. Within the last week or so, I've noticed a little "creak" coming from the front crank every time I pedal under load. It's not super loud, but it's noticeable. It's not the chain, which is fairly new and properly lubed. The motor itself is secure. It doesn't move when I apply side-to-side pressure, but when I grab the crank arms and try to move them side-to-side they move very slightly.

Has anyone else had this issue with a Bafang BBS-02? Is this just a matter of tightening the crank arms (I hope), or a more serious issue with a bearing in the motor?

I don't think tightening the crank arms will solve it, and based on your description, I'm pretty sure its not a bearing. The slight movement of the cranks suggests to me that you have a little bit of play between the bottom bracket and the BBS-02 crank box that inserts into the bottom bracket. I had a similar problem and ended up putting a shim in between them, which I thought solved it, but it is still working loose, so will be working on another fix. If your motor has any play in any direction, this may be your issue.
 

John L.

Member
a little bit of play between the bottom bracket and the BBS-02 crank box that inserts into the bottom bracket

Hmm, Interesting possibility. Unfortunately, that's a bit more complicated for a DIY with my mechanical abilities (or lack thereof). This weekend I'll try tightening crank arms and pedals and see if that works. The motor does not move when I move the crank arms. Hopefully the crank arms (or pedals) are all it is.