Originally Posted by
Campag4life
In answer to last question...unlike your Praxis shown, they run flush which is design intent. This is because the bearings are within the 68mm shell and not outside the shell as you show in your picture. The GXP crank is a long spindle crank which can take advantage of an outboard bearing BB which btw promotes the 'purchase' of a spanner wrench on each side to 'thread together' respective cups for a rock solid unified sleeve that won't creak. Praxis was really born out of the inherit design weakness of PF/BB30.
This is not quite accurate.
In some cases, the crank arm will be flush to the frame. In some cases there will be a spacer. Some Sram BB30 cranks and some Hollowgram cranks, for example, will require a spacer. It depends on which model you get.