BB Compatibility and Interchangeability

[Rick Sanchez]

Hi

 

Just want to know if anyone can tell me how interchangeable BBs are. Is the BB more frame specific or crank specific? I have a BB70 at the moment and was wondering if I could transfer it to a frame that takes a BB30.

 

Any explanation would be greatly appreciated. 

[kennyg]

Most BB's are not interchangeable, in the direct sense.

 

There are an array of adapters that allow you to make your particular conversion possible. Chat to the guys at Rush, I bought an adapter get a few weeks ago that works very well, for exactly your conversion.

[David Marshall]

Times have changed.  The threaded BBs were (almost) all interchangeable and they were crank specific.  Press fit ones are frame and crank specific and you can generally get an insert to convert them to take a crank axle or bearing with a smaller diameter than the designed one.