Waynemarlow
10 kW
ilu said:Amberwolf, you are right. There is definetely some movement. The housing moves up and down, as I ride a lot offroad and with all the bumps and drops the motor probably moves a tiny bit down abd then back up by it's own torque. I tried to prevent this by clamping the bottom part of the chainstay bracket against a chain guard tab in the frame, but I can see now that it is not strong enough. I think I can come up with something more secure with some basic hardware store stuff. What I mean is to just clamp the motor between the top tube and a flat part between BB and chainstays.
We have now 3 motors without any brackets to prevent rotation, all without any problems. Are you sure that the motor is sitting into the chain side of the BB correctly, it has a small taper on it to effectively lock the motor from rotation subject to getting enough torque on the big nut on the other side. Do check as the motor housing can be close to the bikes frame and some bikes need a spacer to push the motor out slightly, as the case won't allow the motor to fully pull into the BB.
The small mount on the non chain side is also really important to get it sitting right and needs to " shimmed " or a custom made spacer between it and the motor. If that is not correctly set then it will not allow the big nut to tension up properly. Best method is to tighten the big nut to say 3/4 torque with it in rough alignment, then measure and properly make exactly the right size spacer on a lathe or use the supplied spacers + washers to get as exact spacer as you can. Then back off the big nut, fit the spacers and semi tighten the bolts, tighten up the big nut and bolts progressively until you reach the right torque. The big nut is much tighter than you think and really you need to extend the supplied spanner to get enough torque on it.