I got an email back from FSA tech support saying that each model of crank could only be used with the specific model of BB that the unit was sold with. They even have a rather sizable "compatibility chart" showing which cranks can be used with various BB's. www.fullspeedahead.com/downloadfly.aspx?.....Cranks.pdf "Please Note: Specific models of FSA MegaExo cranks require specific models of FSA MegaExo BB’s" Well, I guess that what FSA "tech" people told you is similar to SHIMANO's marketing department declaring that you can only use Dura Ace "stuff" with other Dura Ace "stuff" ... Ultegra with Ultegra, 105 with 105, etc. The inner diameter of the bearings is the same 24mm (i.e., the diameter of the spindle for the Hollowtech-II & MegaExo cranks is 24mm). The inner diameter of the Campagnolo bearings is 25mm. The inner diameter of the GXP bearings is 25mm on the driveside & 24mm on the non-driveside -- those wacky guys obviously think they have a better idea. Миру серьёзно нужен опенсорсный велосипед with compatibility in mind.