The S650 Ford Mustang brought a new generation of performance capability to the Mustang platform, and models equipped with the factory Brembo brake systems already have the hardware necessary for serious high-performance driving. For drivers who regularly push their cars on the street, back roads, or track, however, the demands placed on the braking system can quickly exceed what is required during normal driving.

GiroDisc offers a solution with its fully floating 2-piece brake rotors for S650 Mustangs equipped with the factory Brembo iron brake systems. Available for both the front and rear axles, these rotors replace the factory iron discs with high-carbon iron rotor rings, lightweight 6061-T6 aluminum hats, and motorsport-inspired floating hardware.

The result is a brake rotor package engineered around heat management, durability, reduced rotating mass, and consistent performance under repeated heavy braking.

For the S650 Mustang, GiroDisc offers two complementary applications: the girA1-343 front rotor for the factory 390mm 6-piston Brembo system and the girA2-343 rear rotor for the factory 355mm 4-piston Brembo system.

A 2-Piece Approach to S650 Brake Performance

Unlike a conventional one-piece brake rotor, GiroDisc's design separates the rotor ring from the aluminum hat.

The iron rotor ring provides the friction surface required for braking, while the 6061-T6 aluminum hat connects the rotor assembly to the vehicle hub.

This construction offers several advantages for performance applications.

Separating the two materials allows GiroDisc to use high-carbon iron where it is needed for braking while using lightweight aluminum for the center section. This helps reduce unsprung weight and rotating mass compared with a heavier one-piece design.

The fully floating construction also allows the iron rotor ring to expand as temperatures rise without placing unnecessary stress on the assembly.

This becomes especially relevant during repeated high-temperature braking, where rotor temperatures can rise significantly in a short period of time.

High-Carbon Iron Rotor Rings

Both GiroDisc S650 Mustang applications use rotor rings manufactured from a proprietary high-carbon iron casting developed specifically for high-performance braking applications.

The material is designed to withstand the heat generated by repeated hard braking while providing consistent friction performance.

For street-driven Mustangs that occasionally see aggressive driving, this provides additional thermal capability. For track-focused cars, the high-carbon iron construction is intended to withstand the repeated heat cycles and braking loads associated with demanding circuit use.

The front and rear rotor rings are also specifically engineered around the respective factory Brembo brake systems rather than being universal components.

GiroDisc S650 Front Rotors — girA1-343

The GiroDisc girA1-343 is designed as a direct replacement for the factory 390mm 6-piston Brembo iron front rotors used on applicable S650 Mustang configurations.

The front axle experiences a substantial portion of the vehicle's braking load, making rotor cooling and thermal capacity particularly important during repeated high-speed deceleration.

GiroDisc addresses this with a large 390mm rotor and an internal ventilation system featuring 72 curved cooling vanes.

72 Curved Cooling Vanes

The 72 internal vanes are designed to function as a centrifugal pump.

As the rotor rotates, the vanes draw cooler air through the center of the disc and direct it through the internal passages toward the outer edge.

This increases airflow through the rotor and helps remove heat generated during braking.

Improved internal airflow is particularly valuable during repeated braking events because the rotor must continuously absorb and dissipate thermal energy.

The ventilation design works alongside the high-carbon iron rotor material to provide a system intended for sustained high-performance use.

390mm Front Rotor Specifications

The girA1-343 front rotor features:

• 390mm outer diameter
• 36mm rotor thickness
• 34mm minimum thickness
• 72 curved cooling vanes
• 30.3 lbs per rotor assembly
• High-carbon iron rotor ring
• 6061-T6 aluminum hat
• Black anodized hat finish
• Fully floating 2-piece construction

The rotor is designed around the factory 390mm 6-piston Brembo iron brake configuration.

GiroDisc S650 Rear Rotors — girA2-343

The GiroDisc girA2-343 brings the same 2-piece floating rotor architecture to the rear axle.

It is designed as a direct replacement for the factory 355mm iron rear rotors used with the S650 Mustang's 4-piston Brembo rear brake system.

While the rear brakes do not experience the same braking load as the front axle, maintaining consistent rear braking performance remains important for overall brake balance and vehicle control.

The GiroDisc rear rotor uses a high-carbon iron ring and lightweight aluminum hat while incorporating dedicated internal cooling.

48 Curved Cooling Vanes

The girA2-343 uses 48 curved cooling vanes.

Like the front rotor, these vanes act as a centrifugal pump, pulling air into the center of the rotor and forcing it through the internal ventilation passages.

The increased airflow helps dissipate heat during repeated braking and reduces thermal stress on the rotor.

The rear rotor is therefore designed to complement the front GiroDisc setup while maintaining the appropriate dimensions for the factory 4-piston Brembo rear brake system.

355mm Rear Rotor Specifications

The girA2-343 rear rotor features:

• 355mm outer diameter
• 28mm rotor thickness
• 26mm minimum thickness
• 48 curved cooling vanes
• 18.4 lbs per rotor assembly
• High-carbon iron rotor ring
• 6061-T6 aluminum hat
• Black anodized hat finish
• Fully floating 2-piece construction

Lightweight 6061-T6 Aluminum Hats

One of the defining components of the GiroDisc system is the aluminum hat.

Both the front and rear rotors use 6061-T6 aluminum hats, finished with a black anodized coating.

Using aluminum in the hat helps reduce the mass located away from the center of the rotor while maintaining the structural requirements necessary for the brake assembly.

Reducing rotating mass can also benefit the vehicle beyond braking alone. The brake rotor is part of the rotating assembly, so reducing its mass can affect how quickly the wheel and brake assembly accelerate and decelerate.

The reduction in unsprung mass is another consideration for performance-oriented vehicles, particularly where suspension response and wheel control are important.

Reusable Rotor Hats

Another advantage of the GiroDisc 2-piece design is that the aluminum hats are reusable.

The iron rotor ring is the component that experiences direct friction and thermal cycling. Once the ring reaches its specified service limit, the aluminum hat does not necessarily need to be discarded.

Instead, the reusable hat can be transferred to a new GiroDisc replacement ring.

For the S650 Mustang applications, GiroDisc offers dedicated replacement rings:

• D1-343 — Front replacement rotor ring
• D2-343 — Rear replacement rotor ring

This design can reduce long-term replacement costs compared with replacing an entire one-piece rotor assembly every time the friction ring reaches its service limit.

Fully Floating Rotor Hardware

The rotor rings are attached to the aluminum hats using high-strength hardware designed to allow controlled movement between the two components.

The drive pins are manufactured from a high-strength steel alloy and finished with cadmium plating for corrosion resistance.

Spring clips and spring washers secure the assembly while allowing the controlled amount of float required by the 2-piece design.

The result is a rotor assembly that incorporates race-oriented floating technology while remaining suitable for street-driven Mustangs.

Track Capability Without Sacrificing Street Use

GiroDisc developed these rotors for high-performance street driving and demanding track use.

That distinction is important for S650 owners who use their cars in multiple environments.

A dedicated track rotor may prioritize extreme thermal performance at the expense of street characteristics. GiroDisc's floating design is intended to provide the thermal and structural advantages required for aggressive use while maintaining controlled operation for street driving.

The floating hardware is designed to provide the movement required as the rotor heats and expands without creating excessive noise during normal street operation.

Front and Rear GiroDisc Rotors as a Complete Brake Upgrade

The girA1-343 and girA2-343 are designed specifically around the different brake systems used at each end of the S650 Mustang.

The front girA1-343 uses a 390mm rotor with 72 curved cooling vanes and is designed for the factory 6-piston Brembo iron front brakes.

The rear girA2-343 uses a 355mm rotor with 48 curved cooling vanes and is designed for the factory 4-piston Brembo iron rear brakes.

Using both together creates a consistent 2-piece rotor setup across both axles, with each rotor maintaining the correct dimensions and cooling configuration for its respective factory brake system.

For drivers who regularly subject their S650 to repeated hard braking, upgrading both axles can provide a more comprehensive approach than replacing only one end of the vehicle.

Direct Replacement Design

Both GiroDisc applications are designed as direct replacements for the corresponding factory iron rotors.

The front girA1-343 is designed around the factory 390mm 6-piston Brembo configuration, while the rear girA2-343 is designed around the factory 355mm 4-piston Brembo configuration.

This makes the rotor upgrade straightforward for owners already running the appropriate factory Brembo systems.

As with any brake component installation, proper bedding procedures and inspection of the complete brake system are important after installation.

Manufactured in the USA

GiroDisc manufactures the major components of these rotors in-house at its facility in Bellingham, Washington.

The rotor rings, aluminum hats, and drive pins are produced using domestically sourced materials and assembled according to GiroDisc's specifications.

This vertically integrated manufacturing approach allows GiroDisc to control the production of the major components that make up its 2-piece rotor assemblies.

S650 Mustang Fitment

These GiroDisc rotors are designed for specific S650 Mustang configurations equipped with the factory Brembo iron brake systems.

Front — girA1-343

Compatible applications include:

• 2024+ Ford Mustang GT with Performance Package
• 2024+ Ford Mustang Dark Horse
• 2024+ Ford Mustang Dark Horse SC
• S650 Mustang models equipped with 390mm 6-piston Brembo iron front brakes

The girA1-343 is not intended for vehicles equipped with the optional carbon-ceramic brake system.

Rear — girA2-343

Compatible applications include:

• 2024–2026 Ford Mustang GT with Performance Package
• 2024–2026 Ford Mustang Dark Horse
• 2024–2026 Ford Mustang Dark Horse SC
• S650 Mustang models equipped with 355mm 4-piston Brembo iron rear brakes

The girA2-343 is not intended for vehicles equipped with the optional carbon-ceramic brake system.

Always verify the vehicle's existing brake configuration before ordering, particularly on S650 models where brake options can vary.

Brake Rotor Service and Replacement

Like any performance brake rotor, the GiroDisc rings have a specified service limit.

The front girA1-343 has a 34mm minimum thickness, while the rear girA2-343 has a 26mm minimum thickness.

GiroDisc recommends replacing the rotor ring when it reaches its specified minimum thickness. A rotor ring should also be replaced if a crack develops that extends to the edge of the rotor ring.

Because the aluminum hats are reusable, the replacement process can be limited to the worn iron rings rather than requiring complete replacement of the rotor assemblies.

A Performance-Focused Upgrade for the S650 Mustang

The S650 Mustang's factory Brembo brake systems provide a strong foundation for performance driving, but repeated hard braking places significantly greater demands on the rotors than normal street driving.

GiroDisc's 2-piece floating rotors address those demands through a combination of high-carbon iron, lightweight 6061-T6 aluminum hats, curved internal cooling vanes, floating hardware, and reusable rotor hats.

The girA1-343 front rotors provide a 390mm solution for S650 Mustangs equipped with 6-piston Brembo iron front brakes, while the girA2-343 rear rotors provide a 355mm solution for models equipped with 4-piston Brembo iron rear brakes.

Together, they offer S650 owners a brake rotor upgrade focused on thermal management, reduced rotating and unsprung mass, durability, and repeatable performance for both aggressive street driving and track use.

Front Rotor: https://x-ph.com/girodisc-2024-ford-mustang-s650-w-6-pot-brembo-slotted-front-rotors-gira1-343/ 

Rear Rotor: https://x-ph.com/girodisc-2024-ford-mustang-s650-w-4-pot-brembo-slotted-rear-rotors-gira2-343/