Ceramicspeed titanium pulley wheels coatedupgrade your shimano rear derailleur with ceramicspeed coated titanium pulley wheels for reduced friction and extended lifetime the combination of titanium and coated ceramicspeed bearings make these pulley wheels probably the best in the world the pulley wheels are the fastest spinning bearings on your bike making an upgrade to ceramicspeed an effective way to save you precious energy they are extremely wear resistant and will outlive any pulley you