These are lightweight two piece rotors that are made specifically to be used on the B5 S4 with the OEM "18Z" Brembo 6 piston caliper found on the Porsche Cayenne, Audi Q7, and VW Touareg. The only modification required is some minor clearancing on the bottom of the upright. We provide instructions and a video on how to do this. Other than that the discs will bolt directly to the car and work with the "18Z" calipers perfectly. The Girodisc front rotors weight 19.5lbs which are lighter than the stock units. This reduction in rotational and unsprung weight allows for quicker acceleration and suspension response.
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 a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the disc.