Girodisc McLaren 350mm Rear RotorsThe Girodisc system is a direct replacement for the OE disc on all vehicles that came equipped with cast iron rotors from the factory. The central hat section of the disc is made from 6061 T6 aircraft specification aluminum. The disc is made from cast iron to the same specification and material as used by professional racing organizations. It is a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the