BB Compatibility
 

I was looking at the Shimano UN-54 BB on Amazon, and noticed they didn't have a 68x122.5mm option. There is, however, a 68x122mm option, and I was wondering if that was close enough to or is compatible with a 68x122.5mm BB like the one Specialized says my bike has? Of course, 68x122.5 is available in the cheaper Un-26 BB on there. :rolleyes:

The .5mm difference is 2/100 of an inch. Assuming the BB is symetrical (important to find out before ordering), that moves your crankset 1/100 of an inch closer to the frame. That will work fine.

Probably even a 118 will work fine too. +1 in the symmetry part

It could even be that the one listed as 122mm is actually 122.5mm. Certainly nothing to worry about.