GiroDisc A1-012 2-Piece Slotted Front Rotors for 2001-2006 BMW M3 E46 (345 mm)

Vehicle Fitment

• 2001-2006 BMW M3 (E46, front axle, 345 mm rotor setup - ZCP / CSL / standard rotors)

Features

• 2-piece floating rotor design - lightweight aluminum hat + cast iron disc ring for reduced unsprung and rotational mass
• 345 mm diameter vented disc, slotted finish - optimized for better cooling and pad debris clearance
• Curved-vane internal design (48 curved cooling vanes) - pulls ambient air in through hub to ventilate rotor rapidly under hard braking
• Each rotor weighs approx. 17.5 lb vs ~19 lb for stock - improving suspension response and reducing rotational inertia
• Direct bolt-on replacement - compatible with OEM calipers and pads (no major modifications required)
• Floating-pin mounting with Belleville washers & spring clips - allows thermal expansion/contraction without warping or warping-related brake judder
• Hat made from 6061-T6 aluminum (anodized finish) and rings from high-carbon cast iron - designed in USA from domestic materials
• Rebuildable design - rotor rings replaceable (part number D1-012) while reusing hats and hardware, reducing long-term maintenance cost

Specifications

• Part Number: A1-012
• Disc Diameter: 345 mm
• Disc Thickness: 28 mm (new) - minimum service thickness: 26 mm
• Rotor Type: Vented, 2-piece, slotted, curved-vane
• Hat Material: 6061-T6 aluminum, anodized
• Disc Material: High-carbon cast iron (proprietary casting)
• Rotor Assembly Weight: ~17.5 lb per rotor (vs ~19 lb OEM) - ~1.5-2 lb weight savings per wheel
• Sold as a pair (2 rotors, left and right)

Included Components

• 1x Pair of 2-piece front brake rotors (left + right, 345 mm, slotted)
• Floating-mount hardware (drive pins, Belleville washers, spring clips)

Product Description

The GiroDisc A1-012 2-Piece Slotted Front Rotor kit offers a high-performance upgrade for BMW E46 M3 (2001-2006), especially for those equipped with 345 mm front rotors - including ZCP/CSL or standard configurations. By replacing the heavier OEM rotors with lighter, vented, slotted rotors using a 2-piece lightweight hat + disc design, this kit reduces unsprung and rotational mass, enhancing suspension response, brake feel, and overall handling - particularly under hard braking or performance driving scenarios.

The curved-vane ventilation and slotted design help dissipate heat faster and purge pad dust or gasses more effectively, reducing brake fade and improving consistency under repeated stops (track, spirited driving, or heavy traffic). Because the rotor is a direct bolt-on compatible with OEM calipers and pads, it offers an easy upgrade path without major modifications. And with the replaceable disc-ring (hat reuse) design, long-term maintenance becomes more cost-efficient: when rings wear or warp, you can simply swap the rings (via part D1-012) rather than replace the whole rotor assembly.