CeramicSpeed OSPW X Alpha Pulley Wheel System for SRAM RED/Force/Rival XPLR E1 - ALPHA Aluminum Pulley, Carbon Cage,CeramicSpeed's gravel specific OSPW X system for SRAM's 13 speed AXS XPLR E1 comes equipped with 14 tooth and 20 tooth Alpha Disc Pulley Wheels. Their composite teeth material offers prolonged wear protection and noise reduction while the solid aluminum discs eliminate the potential of external objects getting stuck. Nestled in the Alpha Disc pulleys is their patent pending Active Debris Remover (ADR) bearing protective tech feature. ADR combines a