BBSHD Lock Ring won't thread onto motor spindle


New member
Local time
2:37 PM
Apr 17, 2020
I am a good home bike mechanic but the BBSHD gray lock nut will just start to turn and then stops after about 1/8th of a rotation. Its acting as if the threads don't correspond to the motor spindle threads. It is NOT cross threaded. There are no visible defects to the nut or the spindle. The outer black lock ring spins on by hand easily. Luna Cycle support says the anodizing to the gray nut makes it stiff and to just use the tool and muscle it on. I hate to ruin it or worse, the motor unit threaded shaft. I did order a replacement lock nut to see if there is a difference. Anyone else have a problem with a stiff lock ring?
Hi and welcome to the forum!

So with the BBSHD you'll slide it right through the bottom bracket, then add 3 nuts to the motor. The first nut holds the motor upright, the next nut holds the previous nut in place so that the motor doesn't slip down. This nut needs to be tightened as hard as you can. Bafang sell a special tool to tighten this nut, but an adjustable wrench should also work OK.

So I assume you're talking about the lock nut that goes on last? Never had a problem with that. Maybe you can try some sort of lubrication to get it on. Ordering a new one could be a good option too and just see what happens next.

Let us know how you go with it!