Yeah, the frame and cranks will determine what size and kind of BB you get.

Bottom Brackets come sized 68x110 or 70x110 (those are examples, there are many other variations)
The smaller # is the BB shell width, the larger # is the spindle length.

As Travsi corrected me, 68mm is standard for pretty much everything, but some Italian bikes will be 70mm. Then there are 71mm, 73mm and 76mm shells, but don't worry about those.


Engligh vs. Italian threading has to do with the BB threading into the frame.

As far as cranks connecting to the BB, you have a few options here as well, but that's another story...