Shimano XT RT81SS 140mm Centerlock IceTech Disc Brake Rotor

The Shimano Deore XT SM-RT81 Center Lock Disc Rotors feature a 3-layer design comprising of an aluminum core and two outer layers of stainless steel. This construction helps to lower the temperature of the rotor surface by around 100 degrees Celsius compared to rotors made entirely of steel. The rotors also come with an aluminum spider and a standard rotor lockring, but if you want to install them on a 15/20mm axle hub, you'll need to use an external-type rotor lockring.