Shimano dura ace 7700 octalink bottom bracketprecision engineered dura ace 7700 bottom bracket for road octalink splined system original shimano parts guarantees that all components work perfectly for optimum performance and maximum safety and longevity features 22mm diameter chrome moly hollow pipe billet axle reduces weight splined interface provides a more rigid crank assembly compared to tapered counterparts compound bearing structure ball and needle bearings support the spindle to reduc