GiroDisc A1-194 2pc Front Rotors 372x36mm BMW F87 M2 F80 M3 F82 M4 AP Essex

Vehicle Fitment

• BMW F87 M2 and M2 Competition - equipped with AP Racing / Essex CP9660 or CP9668 front big brake kit
• BMW F80 M3 and M3 Competition - equipped with AP Racing / Essex CP9660 or CP9668 front big brake kit
• BMW F82/F83 M4 and M4 Competition - equipped with AP Racing / Essex CP9660 or CP9668 front big brake kit

Fitment Notes

• This rotor is designed for use with the AP Racing / Essex big brake kit - it is not compatible with OEM BMW front calipers or other aftermarket brake systems
• Compatible with both the CP9660 and CP9668 caliper variants of the AP Racing / Essex Radi-CAL front kit
• Direct bolt-on replacement for the AP Racing disc supplied with the Essex/AP BBK - no modifications required
• GiroDisc's iron ring is 36mm thick vs. the AP Racing J-Hook disc's 34mm - confirm clearance in your specific application before ordering
• Sold as a pair (two front rotors)

Features

• Two-piece fully floating design separates the 6061-T6 aluminum hat from the iron disc ring - prevents thermal warp, reduces pad knockback, and allows the rotor to self-center between the pads during braking
• GiroDisc proprietary high-carbon cast iron rotor rings poured in the USA and machined in-house at GiroDisc from start to finish - consistent metallurgy and dimensional accuracy across every rotor
• Curved directional vane design acts as a centrifugal pump, forcing cooling air through the disc to improve heat dissipation and reduce fade under sustained track loads
• Cadmium-plated high-strength alloy steel drive pins transfer braking torque load while maintaining full axial and radial float between hat and disc - secured by Grade 12 cap screws with hardened washers
• Anti-noise spring washers on the rotor side eliminate cold-weather rattle while preserving full float at operating temperature
• Approximately 2 kg lighter per rotor than the original AP Racing disc - further reducing unsprung and rotational mass beyond what the BBK itself already achieves
• Fully rebuildable - replace only the cast iron disc rings when worn; retain aluminum hats and hardware for multiple service cycles
• Made in the USA using domestically sourced materials

Specifications

• Part Number: A1-194
• Brand: GiroDisc
• Position: Front
• Rotor Type: Two-Piece Floating
• Diameter: 372mm
• Thickness: 36mm
• Hat Material: 6061-T6 Aluminum (Black Anodized), USA-sourced
• Disc Material: GiroDisc Proprietary High-Carbon Cast Iron, USA-made
• Vane Design: Curved Directional Vanes
• Drive Pins: High-Strength Alloy Steel, Cadmium-Plated (Grade 12 hardware)
• Caliper Compatibility: AP Racing CP9660 and CP9668 (AP Racing / Essex Radi-CAL BBK)
• Country of Origin: USA (domestically sourced materials)
• Sold As: Pair (2 front rotors)

Included Components

• 2x GiroDisc Two-Piece Floating Front Rotors (A1-194, 372x36mm)
• Drive pins, Grade 12 cap screws, hardened washers, and anti-noise spring washers pre-installed

Product Description

The GiroDisc A1-194 is a two-piece floating front rotor set engineered as a direct replacement for the AP Racing discs supplied with the AP Racing / Essex Radi-CAL big brake kit on the BMW F87 M2, F80 M3, and F82/F83 M4. Compatible with both the CP9660 and CP9668 caliper variants, the A1-194 bolts directly onto the existing AP/Essex hat and caliper hardware without modification. At 372x36mm, this is a 2mm thicker rotor than the standard AP Racing J-Hook ring (372x34mm), delivering additional thermal mass and extended service life under repeated high-load braking on track.

GiroDisc's two-piece floating design gives the iron rotor ring freedom to expand thermally without transferring distortion to the aluminum hat, preventing the warping and pad knockback that can occur with conventional fixed-hat rotor designs. The proprietary high-carbon cast iron rings are poured and machined entirely in-house at GiroDisc's facility in the USA, and each rotor assembly is approximately 2 kg lighter per corner than the OEM AP Racing disc it replaces - further reducing the rotational and unsprung mass advantages that the AP/Essex BBK already delivers over the OEM BMW brake package. When the rings eventually wear, only the rings need replacement, making long-term maintenance significantly more cost-effective than replacing full AP Racing assemblies.