Originally Posted by sivat
The 107mm and 110mm shimano bbs have the same length on the driveside. I'm running the 107 with my 75s and the chainline is perfect.
Are you sure?? Have you actually measured with a calipers or did you just eyeball it? I would be very interested in a more precise assessment of your chainline if you don't mind. I've measured mine (110mm UN73 BB with 75s) several times and its off by 2-2.5 mm.
Heres my method.
1. Distance from the outside of the chainring (at the base of the teeth) to the left side of the seat tube.
2. Subtract half of the diameter of the seattube.
3. Subtract half of the width of the chainring.
Maybe I'm being nitpicky here, but that 2 mm is really buggin me and I think it might be responsible for my slight chain buzz.