Oversized pulley wheels reduce drivetrain friction by changing the chain wrap angle around smaller derailleur pulleys. CeramicSpeed's OSPW System for Shimano Dura-Ace 9100/9150 and Ultegra 8000 SS/8050 SS replaces the stock cage assembly with a carbon fiber unit housing a thirteen-tooth upper pulley and nineteen-tooth lower pulley. This configuration reduces friction between thirty-five and forty percent compared to the standard Shimano pulley arrangement, translating to measurable power savings starting at 2.4 watts under laboratory conditions.

The current design incorporates an integrated stop tower that simplifies installation compared to earlier versions. The carbon fiber cage maintains structural rigidity while shedding grams, and the aluminum pulley wheels run on CeramicSpeed bearings available in either standard or coated finishes. Coated bearings extend service life and further reduce friction through a proprietary surface treatment that minimizes bearing race wear. The system includes adjustable spring tension, allowing you to dial in chain wrap characteristics based on cassette range and riding style.

Compatibility matters with this system. The OSPW works with Dura-Ace 9100 mechanical, Dura-Ace 9150 Di2, Ultegra 8000 SS mechanical, and Ultegra 8050 SS Di2 short cage derailleurs. It handles cassettes up to thirty-two teeth on both Dura-Ace and Ultegra platforms. The system does not fit Ultegra 8000-GS or 8050-GS medium cage derailleurs, nor does it work with the clutch-equipped RX800 and RX805 gravel derailleurs. Despite visual similarities, this OSPW is also incompatible with twelve-speed Shimano 9200 or 8100 series derailleurs, which require different cage geometry.... Read More