Shimano Dura Ace R9100 Bottom Bracket Italian

Shimano DURA ACE R9100 Bottom Bracket Italian. The R9100 bottom bracket by Shimano provides smoother rotation with 50% less drag, due to its new seal construction. It also features smaller ball bearings, which are positioned on the outside for lighter weight and better weight distribution. Italian threaded bottom brackets are only compatible with frames that have an Italian threaded bottom bracket shell, because they screw in the opposite direction from a standard BSA bottom bracket