OSPW Aero Alpha Pulley Wheel System for Shimano 9250 and 8150

The CeramicSpeed OSPW Aero ALPHA system for Shimano 9250/8150 derailleurs updates the fastest proven aero derailleur cage to include CeramicSpeed's patent pending ADR bearing protection and quiet performing ALPHA disc with composite tooth profile pulleys. Furthermore, a speed defying pinstripe graphic has been added for a splash of visual motion.

• 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