Girodisc McLaren 390mm Front RotorsThe Girodisc system is a direct replacement for the OE disc however a different brake pad with an annulus (pad swept area) of 66mm or less must be used. This is done to keep the rotor weight at a reasonable level. If we manufactured a rotor with the same annulus as the OEM CCM rotors they would be unnecessarily heavy. We can provide several different compounds in this shape bases on the customer needs. The central hat section of the disc is made from