How do I know when to replace my rotors? August 31, 2016 13:37 If the rotor’s brake track measures less than 1.55mm thick it needs to be replaced. Related articles Do eTap® HRD 2x11 levers have contact point adjustment? Does SRAM offer more than one brake pad compound option for eTap® HRD 2x11 brakes? Is there a centerlock rotor option? Do the eTap® HRD 2x11 brakes come pre-bled from the factory? Do eTap® HRD 2x11 calipers take the same brake pads as other SRAM HRD 11-speed disc brakes?