The RT99 Disc Rotor features the latest Freeza technology which takes Shimano's revolutionary Ice Tech to the next level. Shimano uses a 3-layer structure with aluminum core and stainless steel outer layers and additional aluminum cooling fins to reduce rotor surface temperature approximately 150 degrees Celsius compared to all-steel rotors.
Cooling fins take heat from the brake track and expel it into the air - not the caliper. Dramatically cooler rotors equals dramatically cooler calipers and fluid. This incredible heat reduction eliminates a host of potential disc brake issues and works to create a braking system of incredible power that is virtually free of any fade.
Requires SM-HB20 external-type rotor lockring when installing onto 15/20mm axle hub