GIRODISC REAR IRON ROTOR CONVERSION FOR 991 AND 992 PORSCHE 911 GT3 / GT2 RS / 718 GT4 RS (W/ PCCB) [A2-154]
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GiroDisc Rear Iron Rotor Conversion for 991 and 992 Porsche 911 GT3 / GT2 RS / 718 GT4 RS (w/ PCCB)
Porsche 991 GT3 rear rotors from GiroDisc are a 2-piece, fully floating iron rotor conversion that directly replaces the factory PCCB carbon ceramic rear discs on the 991 and 992 Porsche 911 GT3 and GT2 RS and the 718 GT4 RS. These GiroDisc Porsche 991 GT3 rear rotors are a direct replacement iron rotor for the OEM PCCB disc with no modifications necessary; they bolt directly to the car and work with the OEM calipers and pads perfectly. The disc is made from GiroDisc’s proprietary cast iron, poured in the USA and machined start to finish in-house, with a curved vane design developed in racing to force cooling air through the disc. Sold and priced per pair.
Why the GiroDisc Porsche 991 GT3 Rear Rotors?
- The GiroDisc Porsche 991 GT3 rear rotors let owners of PCCB carbon-ceramic-equipped cars switch to a 2-piece iron rotor that is far more cost-effective to maintain, especially for track use where carbon ceramic replacement is prohibitively expensive. The central hat is machined from strictly U.S.-sourced 6061-T6 aircraft-specification aluminum, while the disc is GiroDisc’s proprietary cast iron, poured in the USA and machined start to finish in-house. The curved vane design, developed in racing, acts as a centrifugal pump to force cooling air through the disc under hard use.
Direct PCCB Replacement, Works with OEM Pads
- The GiroDisc Porsche 991 GT3 rear rotors are a direct replacement iron rotor for the OEM PCCB disc with no modifications necessary. Unlike the front conversion, the rear bolts directly to the car and works with the OEM calipers and pads perfectly, so there is no change to your caliper or pad selection when converting the rear from carbon ceramic to iron.
Floating Mount and Construction
- The rotor and hat of the GiroDisc Porsche 991 GT3 rear rotors use a floating mount system with 12 high-strength alloy steel drive pins, manufactured by GiroDisc in the USA and cadmium-plated for long-lasting corrosion resistance. These pins take the braking load while maintaining axial and radial float between the hat and disc, secured by class 12.9 cap screws with hardened washers. Anti-noise spring washers on the rotor side let the rotor grow with heat expansion while eliminating the rattle associated with floating rotors, and the float lets the rotor self-center between the pads.
A Reusable Two-Piece Design
- Once the GiroDisc Porsche 991 GT3 rear rotor system is in place, you simply replace the cast iron rotor ring when needed while reusing the aluminum hat, keeping long-term cost well below factory carbon ceramic replacement.
Features
- 2-piece, fully floating rear iron rotor conversion
- Direct replacement for the OEM PCCB carbon ceramic rear disc
- Fits 991 and 992 GT3, GT2 RS, and 718 GT4 RS with PCCB
- Works with the OEM calipers and pads, no modifications
- Proprietary GiroDisc cast iron disc, poured and machined in-house in the USA
- Curved vane design acts as a centrifugal pump for active cooling
- Floating mount with 12 high-strength alloy steel drive pins, cadmium-plated
- Class 12.9 cap screws with hardened washers
- Anti-noise spring washers eliminate rattle; rotor self-centers between pads
- U.S.-sourced 6061-T6 aircraft-specification aluminum hat
- Reusable hat; replace only the cast iron ring when worn
Applications
- Porsche 911 GT3: 991 | 2014-2019 (with PCCB)
- Porsche 911 GT3: 992 | 2021-present (with PCCB)
- Porsche 911 GT2 RS: 991 | 2018-2019 (with PCCB)
- Porsche 718 Cayman GT4 RS: 982 | 2022-present (with PCCB)
Notes
- Sold and priced per pair (one set of rear rotors)
- Direct replacement iron rotor for the OEM PCCB rear disc. No modifications necessary; works with the OEM calipers and pads. Confirm your car has PCCB carbon ceramic rear brakes before ordering.
- This is the rear conversion. The matching front conversion (A1-154 for 991, A1-276 for 992) requires the 991 GT3 iron-rotor pad shape; the rear works with OEM pads.
- This is the complete iron rotor conversion. When the rings wear, only the cast iron ring is replaced while the aluminum hat is reused.
- Stock photography may not depict the actual product.
Frequently Asked Questions
- What do the GiroDisc Porsche 991 GT3 rear rotors replace? The GiroDisc Porsche 991 GT3 rear rotors are a 2-piece iron conversion that directly replaces the factory PCCB carbon ceramic rear discs on the 991 and 992 GT3 and GT2 RS and the 718 GT4 RS, moving you to a serviceable, cost-effective iron rotor.
- Do the GiroDisc Porsche 991 GT3 rear rotors need special pads? No. Unlike the front conversion, the rear rotors are a direct replacement for the OEM PCCB disc that works with the OEM calipers and pads with no modifications necessary.
- Which models do the GiroDisc Porsche 991 GT3 rear rotors fit? The GiroDisc Porsche 991 GT3 rear rotors fit the 991 and 992 GT3 and GT2 RS and the 718 GT4 RS, in each case where the car is equipped with factory PCCB carbon ceramic rear brakes. Confirm your car has PCCB before ordering.
- Why convert from PCCB carbon ceramic to the GiroDisc Porsche 991 GT3 rear rotors? The GiroDisc Porsche 991 GT3 rear rotors move you to a serviceable 2-piece iron rotor that is far more cost-effective than replacing factory carbon ceramic rotors, especially for track use. When the rings wear you replace only the cast iron ring and reuse the aluminum hat.
- What are the GiroDisc Porsche 991 GT3 rear rotors made of? The GiroDisc Porsche 991 GT3 rear rotors use a disc of GiroDisc’s proprietary cast iron, poured in the USA and machined in-house, with a U.S.-sourced 6061-T6 aircraft-specification aluminum hat and a curved vane design that forces cooling air through the disc.
About GiroDisc
GiroDisc designs, manufactures, and sells 2-piece, fully floating brake rotors for a wide range of performance vehicles. Every major component, including the hats, rotor rings, and drive pins, is manufactured in-house at their facility in Bellingham, Washington, from domestically sourced materials. GiroDisc rotors use a proprietary cast iron ring formulated for superior metallurgy and thermal performance, paired with reusable machined-aluminum hats that reduce the long-term cost of maintaining a high-performance brake system. The 2-piece floating design sheds unsprung and rotating mass while remaining street-friendly, delivering race-proven braking for track and street use alike.
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- Please review the product dimensions carefully to ensure the right fit for your space
- Color may vary slightly due to lighting and screen settings
- Materials and finishes are selected for both durability and visual appeal
- Some items may require simple assembly upon delivery
- Perfect for both everyday use and long-term comfort
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Product Size Guide
Please refer to the general size reference below to better understand how this product may fit into your space. Dimensions may vary slightly depending on the design and materials.
| Category | Small | Medium | Large |
|---|---|---|---|
| Decor & Accessories | Up to 10″ | 10″ – 20″ | 20″+ |
| Tables | Up to 30″ | 30″ – 60″ | 60″+ |
| Seating | 1 Seater | 2–3 Seater | 4+ Seater |
| Storage Units | Compact | Standard | Large Capacity |
| Lighting | Small Fixture | Standard Fixture | Large Fixture |
Note: For exact product dimensions, please refer to the specifications section above. This guide is intended as a general reference only.



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