Features: Shimano SM-RT64 rotors offer secure & easy set-up with the proven Centre-Lock mounting system Precision cut stainless steel braking surface improves pad clearing in muddy conditions while aiding cooling underhigh load Rotor contact surface has been developed for excellent pad clearing & cooling which increases pad performance & life Alloy spider supports rotor surface, increasing rigidity & reducing weight Comes complete with steel lockring Average weight for 160 mm rotor with lockring is 153 grams