BBAddict wrote:
I understood that the Rotor cranks were Shimano BB30 compatible. Did you have to do anything special in terms of adaptors or anything to get a Rotor onto a GXP BB?
There are BB standards: namely by diameter and width. Examples of which are pressfit 86 mm wide, standard English 68 mm wide, and BB30 (not sure about the exact dimensions).
BB86 refers to the fact that the bottom bracket area is now 86 mm wide, which incorporates the width of the cartridges. It accepts traditional width (i.e. non BBb-30 type) crankset
Plasma 3 are pressfit, BB86 type, which means it will accept any cartridges made to that spec. Shimano (and Rotor), FSA, and GXP all make pressfit bottom brackets that fit into the shell.
Then there are crankset standards. Shimano and Rotor have a spindle that is 24 mm wide throughout, and GXP is 24 mm on the drive side tapered to 22 mm on the NDS. So a Rotor spindle will not work with a GXP cartridge and vice versa.
If you need to get a Rotor crank onto the frame, just buy the shimano bb86 road pressfit bottom brackets and you are good to go. Fyi, shimano never made BB30 cranksets, though rotor does have the 3D+ which is compatible with BB shells that can accommodate BB-30 bottom brackets.
Which is to say, all very confusing.