The Formula 2-piece rotor is a revolution for disc brakes. Like the one-piece rotor, the steel braking surface has been tested and optimized to compensate thermal expansion and to ensure even pad wear. The revolution lies in the technique of how the aluminum spider is connected to the outer steel ring. Unlike other rotors on the market, the Formula 2-piece rotor is able to compensate for radial expansion caused by high temperatures. This is achieved by the unique design of the spider and how it connects to the stainless steel rotor. In addition, by using modern technologies like Finite Element Analysis (FEA), Formula was able to increase torsional and lateral stiffness without adding any weight. Plus Italian stuff is just plain sexy.