Hi all, struggling to get this catridge bottom bracket (UN55) installed on the non-drive side.
Do the non-drive side inserts come in different sizes?
I don’t know if I should just lever the crap out of this and try to get it the final way in.
BB is from the local co-op, so it’s a good chance the 2 parts weren’t originally to be.
by shnookumsfpv
4 Comments
Could be a 73mm BB in a 68mm shell?
Looks like you’ve got it in about halfway so it should work. Sometimes the cartridge of the bb doesn’t sit right when you torque driveside which makes it difficult to install the cup. Back off driveside and tighten the cup until a few threads are hanging out of the frame. Then torque driveside, followed by cup.
Hope this helps!
Some people might have it in their head that there’s some kind of equivalency or cross-compatibility between adapter cups. There isn’t necessarily, neither between models/brands nor between sizes. Obviously sometimes you might get away with it, but then sometimes not, and then either something like this happens or there’s an OD/ID mismatch and it creaks or gets stuck or it was a cup for a 73 and the stop point isn’t where it’s supposed to be or etc.
If it’s greased and you’ve applied reasonable torque, you’ve done what you can. Just buy a new BB.
Few days ago I installed new UN55 73mm on my Trek 970. I wasn’t able to thread in the left cup after installing the drive side cartridge. So I removed the cartridge, installed the left side cup half way, and threaded in the cartridge all the way in. After that wasn’t’ able to fully tighten the the left cup, about 1 or 2 mm was left between the bracket shell and the cup. Didn’t want to risk of damaging the plastic cup.
#