As before, you need a truvativ gxp crank to go with this BB.
On GXP bbs the drive side bearing is ever so slightly larger than the non drive side.. for absolutely no reason whatsoever. They just wanted to be different.
partly true: there is a corresponding 'step' on the spindle so that when you tighten up the crank bolt on the non drive side you just fasten it really tightly on to the non drive side bearing alone, rather than preloading both the bearings like you do with that little cap
thingy on shimano ones.
I would have thought that this was an attempt at avoiding ham fisted over-the-top side to side preload on the bearings (and an early death!) however truvativ gxp bottom brackets are nevertheless not renowned for their logevity, and there have been many stories on here of non drive side crank arms coming loose and then knackering th splines. So not an altogether successful design!
That said, I do have a set of gxp's that have enduro bearings in them now and have always been on nice and tight. I check the crank bolt every so often but it has never loosened in the 2 years I've had it.
[EDIT: oh, coatsey said it. In about a third as many words as me!]