Originally Posted by
stomppow
Thanks Dutret.
Hmm, so if I were to get an Omnium, I would be stuck with whatever BB it came with (105mm length) and I wouldn't be able to detach the cranks to switch them onto a 128mm bb?
sort of. The spindle is part of the cranks so you can't change that. The bb itself is just two bearing cartridges in cups to connect them to the bike. You would be able to put it in quite easily but once in the bearings would be too far apart to install the crank.
Originally Posted by
stomppow
Okay so I guess mountain it is. But, what happens with the space in the BB for the derailleur attachment which I won't have, a spacer I guess?
mtb BBs are spaced to make up for bb shells that are too small not vice versa.
see sheldon for chainline specifics. I would probably just run the ring on the inside with a guard.