^^ You just cinched things down too tight. It's not the bearings' fault: ball bearings can only take so much side-load pressure.
The bearing pressure on an FSA Mega-EXO is similar to how pressure is applied in tightening a headset. The BB spindle stays with the drive-side crank arm and is passed through the bearing, as you did. NOW, when you put the non-drive-side crank arm on, you leave the pinch-bolts loose and tighten the cap (much like a headset top cap) to take up the side-play slack, then tighten the pinch bolts.
That was where you errored: ONLY snug the cap enough to eliminate the side-play. If you tighten the cap enough to where the BB does not spin freely, back the cap bolt off some until it does. Once you're sure you have the right balance of free-spinning and no side-play (runout), then tighten the pinch bolts on the crank. As an added measure, take another snug on the cap bolt afterward just to ensure it won't back out (it can't change anything once the pinch bolts are tight).
Originally Posted by Mark Twain
"Don't argue with stupid people; they will drag you down to their level and then beat you with experience."
Last edited by dminor; 05-14-09 at 03:17 PM.