Shimano SM-RT10 rotors offer secure and easy set-up with the proven Centre-Lock mounting systemPrecision cut stainless steel braking surface improves pad clearing in muddy conditions while aiding cooling under high load,Rotor contact surface has been developed for excellent pad clearing and cooling which increases pad performance and life,Alloy spider supports rotor surface, increasing rigidity and reducing weight,Comes complete with steel lockring,For use with resin pad only.