ksl said:Thinking of changing to compact cranks. I have a 2005 Giant TCR2 Composite, which has a 2005 Ultegra 10 speed 52/39 crank/bb.
The various integrated cranksets (eg FSA) come with different BBs - I found a FSA compact crank on sale with an "Italian" BB, as well as another one with a 107mm BB.
Questions:
1. does "Italian" means Campy compatible and "English" means Shimano compatible? Is this an issue with my frame's BB shell? Will an Italian BB fit my frame?
2. do different BB sizes (eg 107mm, 108mm, ISIS) all fit all frames? Or do they have to match the BB shell in each frame? I guess they may result in different Q-factors, but such small differences aren't important to me.
Thanks for the help
1. English or Italian refers to the BB shell threading and width. The Italian will NOT fit your frame, which has an English threaded BB. Shimano and Campy both make Italian and English BBs.
2. Generally, English threaded frames will accomodate the English threaded BBs and the same for Italian threaded frames with Italian BBS. The BB size refers to the length of the spindle and matches a specific crankset usage to provide the correct chain line. You need to choose the BB length that is correct for the crankset and usage that you intend. You have to be careful though, as different models and brands may or may not be interchangeable.
For example, Campy Chorus requires a 102mm BB for double use but a 111mm for Triple use. However the Campy 111mm asymmetric BB for triple is not interchangeable with the Campy Centaur symmetric 111mm BB which is intended for use with the Centaur double crankset or a Centaur triple with a 28.6mm diameter seat tube frame.
For an integrated BB/crankset set-up , you should OK for your Giant frame with any English threaded set. To select a non-integrated, you need to make sure that you select the correct spindle length and type (Isis, square taper, etc..) for your crankset and intended use (double or triple).