CenterLock rotor mounts are our preferred method for attaching rotors to our hubs. It provides even pressure across the disc rotor, so its less likely to warp due to uneven torque and its simply faster and easier to install and remove. The XT M8010 Centerlock Rotor Lockring is perfect to keep in the toolbox just in case you might need it on a trip. The lockring is compatible with 12, 15, and 20mm axles and Centerlock rotors and requires an external BB tool to torque the lockring to the hub.