Shimano SG-S7051 Alfine 11-speed Di2 disc internal hub gear, 135 mm, 36h, black

The Alfine 11 speed Di2 specification internal gear hub runs on needle bearings for increased durability and high drive efficiency Helical internal sprockets increase durability, perform better with high torque loading and provide a constant engagement for a smooth and quiet operation Oil bath lubrication system increases durability and reduces friction in the hub, while Labyrinth seals improve sealing performance both resulting in extending service life Double roller silent clutch engagement also gives a smoother quieter shift Top normal internal structure for improved tolerance when shifting while riding under load Alfine hubs use pedal power to aid down-shifting resulting in fast and accurate shifts with an exceptionally light feel Shimano's precise manufacturing abilities have enabled them to construct the Alfine internal hub to be there most efficient yet 409% Gear ratio Centre-Lock disc rotor compatible 135 mm O.L.D. spacing Weight: 1,670g