Girodisc 350mm Slotted Rear Rotors For Porsche 911 Carrera/C4 (991.1)

USP Motorsports is pleased to offer products from one of the top 2-piece brake rotors manufacturers, GiroDisc. GiroDisc's fully-floating design uses tension hardware to ensure that our rotors are silent on the street, but ready to go on the track. By specializing in this area, they have been able to dedicate their efforts to push their engineering and manufacturing to the highest levels in the industry. When GiroDisc was founded in 2003, they made their mission to design and manufacture 2-piece brake rotors that would perform flawlessly at the limits.

The Girodisc system is a direct replacement for the OE disc with the addition of our provided caliper spacers and longer bolts to accommodate the larger 350mm rotor. 

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.

The rotor and hat have a floating mount system, which utilizes 10 high strength alloy steel drive pins, manufactured by Girodisc in the USA to our own specifications 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.

Note: for all 991 base Carrera cars, please use the S/4S/GTS rear pad shape for full sweep across the rotor. If you have any questions, contact Girodisc and they will be happy to point you in the correct direction!

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