Ceramicspeed oversized pulley wheel systemthis ceramicspeed oversized pulley wheel system is 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 bearings this revolutionary ospw system is developed produced and assembled by hand in denmark this plug and play product is the result of an in depth development process