Here is the beauty of these two-piece 13-inch rotors. The rotors are built in such a way that they're considered floating rotors. Every other disc mounting screw has approximately 0.001 inch of play and is held in place with a spring bushing. The spring keeps constant tension on the bushing and fastener, eliminating rattles or squeaks from road vibration. The two-piece hat and rotor system has distinct advantages over a one-piece, including weight savings; nearly 8 pounds is saved on each front corner of the vehicle. Additionally, the direction vanes and cross-drilling help to further dissipate heat. These two features result in more consistent braking and heat dissipation of the rotor.