Girodisc Porsche 390mm Rear RotorsThe Girodisc system is a direct replacement iron rotor for the OEM PCCB disc, no modifications are necessary. The disc will bolt directly to the car and work with OEM calipers and pads perfectly. The central hat section of our rotor is made from strictly U. S. sourced 6061 T6 aircraft specification aluminum. The disc is made from our own proprietary cast iron, poured in the USA and machined from start to finish in house at Girodisc. The rotor utilizes