GIRODISC A2-322SL Rear Left Brake Rotor for BMW M3 (G80 / G81) / M4 (G82 / G83) 2021-

These GiroDisc 2-piece rotors are a direct replacement for the 380mm carbon ceramic rear rotors on the  BMW M3 (G80 / G81) / M4 (G82 / G83). 2-piece, fully floating assemblies utilize the factory calipers and require no modifications other than switching the rotors and pads. These rotors use the factory iron pad shape with the carbon ceramic calipers.

The rotor rings are machined from a proprietary casting made of high-carbon iron formulated to GiroDisc’s specifications. This superior metallurgy results in a rotor that holds up better, and the 72 curved vanes act as a centrifugal pump pulling air in through the hub to effectively cool the rotors under hard use. The 2-piece design means a reusable hat which can be attached to new rings when they need to be replaced.

All major components including the hats, rotor rings, and drive pins are manufactured in-house at facility in Bellingham. The hat is made from 6061-T6 aluminum and coated in a black anodize finish. The drive pins are made from a high-strength steel alloy and cadmium-plated for corrosion resistance. All rotors are assembled with spring clips and Belleville washers for race-ready float while also being street-friendly with no noise from loose hardware.

The minimum thickness at which recommend replacing these rings is 26mm. Also recommend replacing them if a crack leads to the edge of the ring.