CeramicSpeed OSPW Pulley Wheel Aero Alpha System for Shimano 9250/8150 - Coated Races, Aluminum Pulley, Carbon Cage, Black EA Cage Assembly

Injection Molded Carbon Fiber reinforced PA Aero cage reduces aerodynamic drag on the rear derailleur by up to 60% and offers new levels of strength and durability Alpha disc pulleys are paired with a composite, narrow-wide tooth profile to help prevent debris from external objects getting stuck The 13-tooth upper and 19-tooth lower Alpha pulley wheels feature ADR bearing protection that completely encloses the bearings This OSPW System has handbuilt CeramicSpeed coated bearings installed in each pulley Grade 3 Silicon Nitride ball bearings are 400% smoother, 128% harder and 58% lighter than standard steel balls normally used in the bicycle industry 4 customizable spring tension settings for optimal setup Compatible with Shimano Road Dura-Ace R9250 and Ultegra R8150 12-speed rear derailleurs It is not possible to add these pulleys to a previous generation OSPW Aero cage