Girodisc 410x36 Front Brake Discs for Porsche 911 (991) GT3, GT3 RS, and GT2 RS (2013–2019) – 718 (982) Cayman GT4 RS (2021+) wi

The Girodisc A1-154 front brake discs, measuring 410 × 36 mm, improve thermal management during repeated braking on the Porsche 911 (991) GT3, GT3 RS, and GT2 RS models equipped with carbon-ceramic rotors (2013–2019), Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+). Their cast-iron tracks and aluminum bowls form a floating assembly designed to manage thermal stresses and facilitate the replacement of tracks under wear. Sold in pairs, with one left-hand rotor and one right-hand rotor.

These rotors are intended for the front axle of compatible vehicles in the configuration listed below. They retain the compatible caliper mounting; any required spacers and brake pad specifications must be followed.

The curved internal cooling fins channel air through the rotor to dissipate heat during repeated braking. The floating mounting limits stresses caused by thermal expansion differences between the rotor and the housing and helps the rotor center itself between the brake pads, maintaining consistent contact under heat.

The hub is made of 6061-T6 aluminum. The high-strength steel drive pins are cadmium-plated to resist corrosion. They are secured by Class 12.9 bolts and hardened washers. Spring washers minimize cold-mounting noise while allowing the necessary compression for the floating mount.

New pads must be installed with new rotors or brake pads. Their shape and compound must match the mounting, cast iron, and intended use; follow the specific requirements for this part number and perform the prescribed break-in procedure.

On compatible vehicles originally equipped with carbon-ceramic rotors, this pair provides a conversion solution to high-quality cast-iron rotors. It allows you to remove and store the expensive original carbon-ceramic rotors to preserve them during heavy-duty use, while reusing compatible calipers. Use new brake pads suitable for cast iron and adhere to the pad shapes and any spacers specified by the part number. Replaceable brake pads reduce the cost of replacing braking surfaces in heavy-duty uses and offer a choice of trims to tailor bite and pedal reaction to the intended use.

Specifications for Girodisc A1-154 rotors for compatible vehicles

• Brand: Girodisc
• PartNumber: A1-154
• Position: front
• Sizes (diameter × thickness): 410 × 36 mm
• Vehicles and models: Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019); Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+)
• Braking surface material: high-resistance cast steel
• Packaging: Pair of complete rotors, one left and one right, with disc bells.
• Hub: 6061-T6 aluminum
• Construction: two-piece floating mounting design
• Catalog part number: D1-154. Verify compatibility with the caliper generation before replacement.
• Internal ventilation: directional curved fins
• Minimum thickness: 34 mm
• Original rotor diameter: 410 mm
• Manufacturing of main components: United States

Vehicles compatible with Girodisc part number A1-154

• Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019)
• Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+)

• Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019): For factory PCCB; at the front, use the pad shape for the cast-iron rotor version.
• Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019): Use the brake pad shape for the Porsche 911 (991) GT3 with cast-iron brakes, which is shorter radially than the PCCB pad.
• Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+): For factory PCCB; at the front, use the pad shape for the cast-iron rotor version.
• Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+): Use the brake pad shape from the Porsche 911 (991) GT3 with cast-iron brakes, which is shorter radially than the PCCB pad.

Each application is subject to its specific brake system configuration, calipers, and any requirements for brake pads or spacers. Please verify these conditions before ordering.

Girodisc A1-154 Mounting Requirements

• Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019): For factory PCCB; on the front, use the pad shape designed for the cast-iron rotor version.
• Porsche 911 (991) GT3, GT3 RS, and GT2 RS with carbon-ceramic rotors (2013–2019): Use the brake pad shape for the Porsche 911 (991) GT3 with cast-iron brakes, which is shorter radially than the PCCB brake pad.
• Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+): For factory PCCB; at the front, use the pad shape for the cast-iron rotor version.
• Porsche 718 (982) Cayman GT4 RS with carbon-ceramic rotors (2021+): Use the brake pad shape from the Porsche 911 (991) GT3 with cast-iron brakes, which is shorter radially than the PCCB pad.

Brake Pads and Braking Systems for Compatible Vehicles

Choose brake pads whose shape is compatible with the calipers, the track, and/or the A1-154 rotor, and whose compound is suitable for sport driving or track use. The Endless, pagid Racing, or Ferodo Racing ranges may be considered after verifying the appropriate part number.

For intensive use, we recommend compatible aviation-grade hoses and a high-performance brake fluid that meets the vehicle’s specifications, along with proper bleeding and fluid replacement. This recommendation complements the mounting, which is compatible with the original hydraulic system.

Maintenance of the Girodisc mounting on compatible vehicles

Replacing the pads alone helps keep the calipers in good condition. Reusing a caliper for up to three pad replacements is subject to inspection of its condition, its mounting components, and the mounting instructions; this number does not constitute a guaranteed service life. Use a new mounting component each time you replace the pads.

FAQ — Girodisc A1-154 for Compatible Vehicles

What are the sizes of the A1-154 discs for my vehicle? The part number shown measures 410 × 36 mm and is mounted on the front axle. The diameter alone is not sufficient: also check the brake system type and mounting requirements.

Is the product sold in pairs? Yes. It includes a left and a right disc for the same axle. Both discs are shipped with their disc bells.

Do I need to replace the brake pads on my vehicle?Yes. Always install new brake pads with new brake discs or new brake pads. Use a compound suitable for cast iron and your specific use. Use the Porsche 911 (991) GT3 brake pad shape for cast-iron brakes, which is shorter radially than the PCCB pad.

How do I identify the left and right sides? Girodisc rotors come with a label attached to each rotor: LEFT for the left side and RIGHT for the right side, as viewed from the direction of travel. On a left-hand-drive vehicle, “LEFT” corresponds to the driver’s side and “RIGHT” to the passenger side. Follow these labels and the instructions. On models with curved internal fins, the rolling direction depends on this internal ventilation; the surface grooves alone are not sufficient to determine the side.

How do I break in this mounting on my vehicle? Follow the Girodisc procedure and the brake pad manufacturer’s instructions to build up an even transfer ply. The PDF documents below detail installation and break-in.

PDF Documents for Mounting and Break-in

We have included two PDF documents below: an instruction manual for installing and breaking in the discs, and an instruction manual for installing new tracks on existing bowls. Consult the document that applies to your specific task before you begin.

Key Features of the Girodisc A1-154

• 410 × 36 mm size for front braking on compatible vehicles.
• 6061-T6 aluminum rotor and floating mount to manage thermal stresses.
• Internal ventilation via curved fins to dissipate heat.
• Replaceable pads to maintain a two-piece mounting.
• Left/right pair identified for mounting.
• Aluminum rotors to control the unsprung mass and rotating mass of the conversion kit.