GiroDisc A1-081 2-Piece Front Rotors Ford Mustang S197 GT500 Boss 302 GT Brembo

Vehicle Fitment

• 2007-2012 Ford Mustang Shelby GT500 (S197, 355 x 32 mm front rotors)
• 2012-2013 Ford Mustang Boss 302 (S197, 355 x 32 mm front rotors)
• 2011-2014 Ford Mustang GT with factory Brembo brake upgrade (S197, 355 x 32 mm front rotors)
• 2004-2010 Ford Mustang S197 variants equipped with factory 355 x 32 mm front rotors and 4-piston Brembo calipers

Fitment Notes

• Front axle only - sold as a pair (2 rotors); for the matching rear axle set, see GiroDisc A2-081
• Fits S197 Mustang models equipped with the factory 355 x 32 mm front rotor and 4-piston Brembo caliper combination - confirm your rotor size before ordering; standard GT models without Brembo brakes use a smaller rotor and are NOT compatible
• 2013-2014 Shelby GT500 models use a larger 380 mm front rotor with a different caliper - these require GiroDisc A1-091, not A1-081
• Direct OE replacement - bolts to factory front hubs and works with OE Brembo calipers and pads without modification
• Factory brake bias and ABS calibration are fully preserved
• When the cast iron rings wear out, only the replacement rings need to be purchased - hats and hardware are fully reusable (replacement ring part number: D1-081)

Features

• Two-piece floating rotor construction - cast iron rotor ring joined to a 6061-T6 aircraft-specification aluminum hat via a floating drive pin assembly; replaces the heavy single-piece cast iron hat of the OE rotor
• Significant weight reduction - GiroDisc A1-081 rotors weigh approximately 20.2 lbs per rotor versus 25 lbs for OEM, saving approximately 4.8 lbs per corner (9.6 lbs total at the front axle); all savings are in unsprung and rotational mass
• Curved vane disc design - internal vane geometry developed in racing to function as a centrifugal pump, actively drawing cooling air through the disc during rotation for superior thermal management versus the OE rotor
• Fully floating mount system - 8 to 10 high-strength alloy steel drive pins, manufactured by GiroDisc in the USA to proprietary specifications and cadmium plated for corrosion resistance; pins carry all braking torque loads while allowing the disc to float axially and radially relative to the hat
• Anti-noise spring washers - allow thermal growth of the disc ring without binding against the hat, eliminating rattle and clicking while maintaining true float under load
• Rotor self-centering - floating design allows the disc to self-center between pads on release, reducing residual drag and promoting even pad wear across the swept surface
• Slotted rotor surface - slots continuously sweep brake dust, gases, and debris from the pad contact face for consistent bite and reduced glazing during hard or sustained braking
• Proprietary GiroDisc cast iron alloy - poured in the USA and machined entirely in-house at GiroDisc; same material specification used by professional racing organisations
• Rebuildable - when rings wear, only the cast iron ring needs replacement; aluminum hat and drive pin hardware are fully reusable
• Manufactured entirely in the USA

Specifications

• Part Number: A1-081
• Product: 2-Piece Floating Front Brake Rotor Set
• Quantity: 2 rotors (1 pair - full front axle set)
• Rotor Dimensions: 355 x 32 mm
• Rotor Style: Slotted
• Construction: Two-piece floating - cast iron disc ring + 6061-T6 aluminum hat
• Hat Material: 6061-T6 aircraft-specification aluminum (US-sourced)
• Disc Material: Proprietary GiroDisc cast iron (poured and machined in USA)
• Drive Pins: 8-10 high-strength alloy steel, cadmium plated, per rotor
• Pin Fasteners: Grade 12 cap screws with hardened washers
• GiroDisc Rotor Weight: approx. 20.2 lbs per rotor
• OEM Rotor Weight: approx. 25 lbs per rotor
• Weight Savings: approx. 4.8 lbs per rotor / 9.6 lbs per front axle set
• Compatible Caliper: Factory 4-piston Brembo (S197 GT500 / Boss 302 / GT Brembo)
• Axle: Front only (rear set = A2-081; front replacement rings only = D1-081)
• Installation: Direct bolt-on; no modifications required
• Country of Manufacture: USA

Included Components

• 2x GiroDisc 2-piece floating front brake rotors (1 pair; complete front axle set)
• All required mounting hardware (drive pins, grade 12 cap screws, hardened washers, anti-noise spring washers)

Product Description

The GiroDisc A1-081 is a pair of two-piece floating front brake rotors engineered as a direct OE replacement for the Ford Mustang S197 in GT500, Boss 302, and GT (Brembo) configurations using the factory 355 x 32 mm front rotor with 4-piston Brembo calipers. They bolt directly to the factory hubs and work with the OE calipers and pads with no modification - factory brake bias and ABS efficiency are fully preserved. The system replaces the heavy single-piece OE rotor's cast iron hat with a CNC-machined 6061-T6 aluminum hat, with the cast iron ring mounted on a floating drive pin assembly rather than being rigidly joined to it.

The weight savings are meaningful at this platform: each GiroDisc A1-081 rotor weighs approximately 20.2 lbs versus 25 lbs for the OE unit - roughly 4.8 lbs saved per corner, or 9.6 lbs removed from the front axle alone. Because this weight is entirely unsprung and rotational, it has a disproportionate effect on vehicle dynamics: less unsprung mass means the front suspension can follow road surface changes more accurately, and less rotational inertia means the brakes can decelerate the wheel more quickly when the pedal is applied and the drivetrain can accelerate the wheel more efficiently on exit. The internal curved vane geometry - developed from racing application - actively pumps cooling air through the disc as it rotates, directly addressing the thermal management limitations of the OE solid-hat design under sustained hard braking.

Important fitment boundaries: the A1-081 covers the 355 x 32 mm Brembo-equipped S197 Mustang variants. Standard GT models without the Brembo option use a different, smaller rotor and are not compatible. The 2013-2014 Shelby GT500 upgraded to a larger 380 mm front rotor and requires GiroDisc A1-091 instead. When the cast iron rings eventually wear beyond their minimum thickness, only the replacement rings (D1-081) need to be purchased - the aluminum hats and cadmium-plated drive pin hardware are fully reusable. The matching rear axle set is GiroDisc A2-081. All GiroDisc components are manufactured in the USA.