Rear

The CeramicSpeed Oversized Pulley Wheel System provides optimization and increased efficiency of the rear derailleur through its extremely low-friction bearings and unique overall design. Features 13-tooth upper and 19-tooth lower, aluminum pulley wheels with Grade 3 Silicon Nitride balls Robust cage crafted from polyamide and carbon fiber for durability and light weight Hardened steel bearing races Compatible with Dura Ace 9200 and Ultegra 8100 series (Fits 11-30 and 11-34 Shimano 12spd Cassette options) Four spring tension settings allow customized setup based on ride conditions Integrated stop tower for simple installation and durability