Lightweight two piece rotors are a direct fit for the VoshMods B5 300mm rear Big Brake kit on the B5 S4.
The central hat section of the rotor is made from strictly U.S. sourced 6061-T6 aircraft specification aluminum. The disc is made from Girodiscs 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.
The rotor and hat have a floating mount system, which utilizes high strength alloy steel drive pins, manufactured by Girodisc in the USA and cadmium plated for a long lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. The pins are secured by class 12.9 cap screws with hardened washers. In order to keep the rotors from making noise when cold, the pins are mounted with anti-noise spring washers on the rotor side which allow the rotor to grow with heat expansion but eliminate the rattle and noise associated with floating rotors. This float also allows the rotor to self center between the pads.
Once the Girodisc system is in place, simply replace the cast iron rotor when needed.