Rockhopper and BBS02 bottom bracket size
I got the mid-drive kit delivered and installed it. I was pretty sure the BB size was 73mm (1997 rockhopper 26"), measured with printouts etc, so I got the BBS02 68-73mm. The motor fits ok, but i can only get the inner threaded ring on it, the one that says 50-60Nm one. It leaves less than 2mm of theeads exposed and the cover ring (says 20-30 Nm) doesn't catch them. By the looks of it, i think the cover is just extra protection, against it coming undone and debris, so i took the bike for a ride anyway, and it performed great. but still would want to go back and fix. Can I find different yhinner rings that would fit? Could the BB be slightly bigger on older mountain bikes? Am I left to grind the bottom tube down from the side? sounds tedious. Any other possible ways?
Hi there, I wouldn't do any grinding. Try installing the main nut very tight - not overtight - but about as tight as you can get it with the install wrench (by hand), then add a universal bracket to keep the motor in place. This is a similar install on my wifes Townie and it works. The nut is hidden behing the bracket.