- With plastic washers - Shell: 8mm Allen head axle bolt

The Dynatron features an American BB with press fit cups and caged bearings. - Compatible with 1-piece cranks - Frame BB Shell is 68mm width by 51.5mm inner diameter - BB Style: American

Get more distance out of every pedal stroke with SRAM's BB30 Bottom Bracket Assembly. It features sealed bearings for a smooth pedal stroke and impressive reliability. Plus, it presses directly into your frame's BB30 bottom bracket shell for reduced weight and increased longevity.