Ceramicspeed oversized pulley wheel system coatedthe coated bearings in the ceramicspeed oversized pulley wheel system give you extended durability and longevity of the product it has been developed for performance optimisation and the watt savings start at 24 watts the cage is made from carbon fibre and reinforced pa while the 17 tooth pulley wheels are made from aluminium and mounted with high quality ceramicspeed coated bearings the revolutionary ospw system is mounted with ceramicspeed c