"Shimano crafted the RT-CL750 as a thicker, tougher centerlock disc brake rotor. Built from 2. 2mm stainless steel, this rotor has improved durability, heat capacity, and resistance to trail debris over standard 1. 75mm rotors. What Our Gearhead® Experts Are Saying:""The thickened construction handles the heat load of long descents without the fade that thinner rotors show when the brake is working hard. Centerlock installation is fast and precise, and the rotor stays true longer under repeated thermal stress."""