I have a BBS02 attached to the bottom bracket of my Trek Dual Sport and I can't seem to keep the motor tight against the frame. I have the Lekkie one nut and have tightened it by hand; then a few taps with a soft mallet. It loosens after a few rides. I don't want to apply so much force that I distort the BB. Any ideas on how to tighten?
Thanks!
The wrench included in the kts will never apply enough torque to keep the motors tight. I torque the nut to 80nms using a torque wrench and special socket for that nut. I also use orange threadlock to make sure it stays tight. I've never had one come loose.
David Schell
www.tinkerbolt-ebikes.com
Hi James,
You're probably aware that there are two small holes on the outer facing of the Lekkie one-nut that accept a 2mm hex wrench for tightening of "Grub-screws" to hold the one-nut in place. I had my one-nut loosen at one point because I was unaware that there were two grub screw accesses and only tightened one.
It might help to remember that a BBS02 is 750 watts--or one horse power and that's the force it's kicking at!
Further what's worked for me is the addition of a torque arm to cinch the bafangs to the frames of my bikes. Johnny N.O. sells one described as; Torque Arm for Bafang Mid Drive motors BBSHD/ BBS02. There are other sellers who carry them as well (Luna / California e-bike). With Johnny you get his distinctive lightening bolt logo as a bonus on the item, support the "small guy" and his prices are great. I installed two from Luna bikes (Before Johnny introduced his torque arm) and along with the Lekkie one nut I have had zero problems with the motors loosening. The torque arms are malleable enough to fit to just about every frame, but strong enough that they don't warp during use.
Lastly there is a cheap-fix using heavy-duty zip ties. You simply zip-tie three or four zips around the bottom of your seat tube and then four or so more zip ties around the motor looping into the seat-tube zips you put on first. Cinch it tight. You'll find you need fairly long zip ties to wrap around the motor. I did that for a while, it worked okay, but I wanted to clean up the look and have gone with the torque arms, and never looked back.