Originally Posted by
vesteroid
to simplify, will a given crank fit into bikes with different bb...so the crank part itself is no different (as in different length, diameter something) just the bb is different.
so for instance I have a giant defy with an ultegra crank. it has a bb30. Can I take that crank off the giant, buy a english bb and install it all on a new bike that needs the english bb (rather than buying a whole new crank and bb)
If your bike has an Ultegra crank and a BB30 BB shell, then it has to be using an adapter since all Shimano cranks are designed to fit threaded BB shells, not oversized. So yes, you should be able to use the Ultegra crank on the new bike. Whether you will need a new BB depends on whether the Giant's adapter utilized the standard Shimano BB or not. New Ultegra BBs run about $30.