alpha Racing's Slipper Clutch for BMW S1000 RR/HP4, CNC machined, to be used with BMW OEM clutch plates or the higher performance alpha Racing WSBK clutch plate kit (Part Number: 2121A008A00-01) available in this SHOP. Extremely responsive clutch feel with advanced anti-hopping clutch technology with precision milled CNC components. Used by professional teams in WSBK. This system prevents downshift overrevs, downshift-braking rear wheel chatter to enable smoother cornering transitions while preserving the engine and reducing tire wear. This "wet" system is to be used with the factory type friction and steel plates, factory basket, factory clutch cover, and a common premium grade motor oil. Heavy duty diaphragm springs are also marked for precise adjustment if you want to experiment with various settings by purchasing additional springs with different ratings. All systems are equipped with a 2 piece hub separated by a 45 degree ramp angle which float on forged steel ball bearings when "slipping". This system does not increase clutch wear to an appreciable extent if installed correctly nor will the system allow for slippage during acceleration. Features: 2-piece hub with 45 degree ramps Racing Pressure Plate Racing Clutch Diaphragm Spring Installation mounting hardware Uses OEM BMW clutch plates or alpha Racing clutch plate kit (sold separately)