Introducing the GiroDisc 2-piece rotors, designed as a direct replacement for the E46 M3 345mm rotors found on Competition Package (ZCP) and CSL models. Each rotor assembly weighs 17.5 lbs compared to the factory rotors' 19 lbs, significantly reducing unsprung weight and rotating mass on the front axle.
Our rotor rings are machined from a proprietary high-carbon iron casting, formulated to GiroDisc's exacting specifications. This superior metallurgy ensures enhanced durability, while the 48 curved vanes act as a centrifugal pump, efficiently cooling the rotors during rigorous use. The innovative 2-piece design features a reusable hat that can be easily attached to new rings (part number D1-012) when replacement is needed.
All key components, including hats, rotor rings, and drive pins, are manufactured in-house at our Bellingham, WA facility using domestically sourced materials. The hat is crafted from 6061-T6 aluminum with a black anodized finish. Drive pins, made from a high-strength steel alloy, are cadmium-plated for superior corrosion resistance. Each rotor assembly incorporates spring clips and Belleville washers, ensuring race-ready float while remaining street-friendly without noise from loose hardware.
Our E46 M3 rotors are compatible with common aftermarket caliper setups, including Brembo calipers from both Porsche 996 and Megane RS swaps, in addition to the stock sliding calipers available on ZCP and CSL models.
**Specifications:**
- Diameter: 345mm
- Thickness: 28mm
- Weight: 17.5 lbs per rotor assembly
We recommend replacing the rotor rings when the thickness reaches 26mm or if a crack extends to the edge of the ring.
Priced and sold per pair.
