I'm trying to rebuild an old Univega MTB. Primary goal is to build a good or decent bike from used parts.
The crankset+bb that was on the bike when I got it was really worn out. I unscrewed it and cleaned the frame carefully. I asked around and found a friend that had a Shimano FC-M391 crankset with its original BB I could get.
When I installed it I just noticed that the new BB axle was ~10mm longer than the one I removed from the Univega. Unfortunately I didn't measure it but I guess it's 123mm. The original from the Univega was 110,6mm.
The new crankset doesn't come close enough to the frame. From what I can see I would like to have it ~10mm closer? I think I got it to come up all the way on the BB-axle.
I thought the BB axle length was specified with the crankset? I looked in the Shimano docs where it says 123mm.
What width should I use for this bike?