Originally Posted by
clengman
Shimano BB un55 will work fine. 113mm (I think) is the most common spindle length for a triple crankset.
Edit: You already have a triple and a functioning BB, right? First get your new crankset and a crank puller and try the new crankset on the existing BB. If you're swapping a triple for a new triple, chances are it'll work. If the smallest ring doesn't clear the chainstays, measure your current spindle and buy a new BB with spindle that's longer.
At the moment, I do indeed plan to keep my BB. I'm asking just because the whole BB choice is somewhat insane to the uninformed. I was vaguely hoping that with the input of a few experienced wrenches, it might be possible to compile a "sticky" guide on the subject since there is so little out there that Google readily finds.