GiroDisc 2-Piece Rear Rotors 2018-2021 Subaru WRX STI

The 2018-2021 WRX STI moved to larger Brembo brakes with yellow calipers. These Giro Disc 2-piece rear rotors replace the factory rear discs on those cars and work with the factory calipers. They take unsprung weight off the rear axle, and the floating iron rings handle heat better than the stock one-piece rotor.

Construction

The center hat is machined from US-sourced 6061-T6 aircraft-grade aluminum. The ring is GiroDisc's own proprietary cast iron, poured in the USA and machined from start to finish in GiroDisc's shop. A curved vane design developed in racing works as a centrifugal pump, forcing cooling air through the disc to keep temperatures in check through long sessions. Lighter rotors also cut rotating and unsprung weight, which helps acceleration and suspension response.

Floating mount, quiet on the street

Ring and hat are joined by 10 high-strength alloy steel drive pins, made by GiroDisc in the USA and cadmium plated for long-lasting corrosion resistance. The pins carry the braking load while keeping axial and radial float between the hat and the ring. Class 12.9 cap screws with hardened washers secure them, and anti-noise spring washers on the rotor side let the ring grow with heat without the cold rattle typical of floating rotors. The float also lets the ring center itself between the pads. Once the system is on the car, you only replace the iron ring when it wears.

Brake pads

Important: these rear rotors require brake pads modified for extra clearance. Standard rear pads will not work. GiroDisc offers the modified pads in several compounds; call us and we will match one to how you drive. The rotors themselves bolt on with no changes to the car.

What's Included

Two assembled rear rotors, one per side, each iron ring already mounted to its aluminum hat. Pads are not included.

Specifications

Fitment notes

Fits the 2018-2021 WRX STI with the factory Brembo rear brakes. It does not fit the regular WRX or 2017 and older STI models. Front rotors: A1-185. The product photo is GiroDisc's representative image of its 2-piece rotors.

Fitment