Originally Posted by Triguy

I disagree that outboard bearings were in any way "standardized." Shimano had Mega Exo of straight 24mm spindle, which worked with "some" FSA cranks; FSA cranks were divided in to GXP, Shimano Mega Exo and another slightly different Mega Exo; GXP had a 24mm spindle with some variation that required a different dd; Campy had their own BB; Zipp had a different BB.

The way things are now, BB30 is similar to standard BB in that lots of cranks can work if you have the right adaptive BB/spacers. No different changing spacers than changing actual BB cups.