The pulley wheels are the fastest spinning bearings on your bike. An upgrade to ceramic bearing therefore is the most effective upgrade. C-Bear ceramic pulley can be used both for road, cyclocross and MTB.
Shimano-SramCampagnoloFor Road/Race use Only.
11 SpeedFull Ceramic only for Race/Road
Sram 11 SpeedXX1XO1Force CX1Force 1Rival 1