Girodisc D2-238 Porsche 991 Cup / GT4 Clubsport Rear Replacement Rotor Rings (380x30)
The Girodisc D2-238 Rear Replacement Rotor Rings are precision-engineered replacements for Girodisc two-piece rear rotors on the Porsche 991 Cup Car and Cayman GT4 Clubsport. Designed to restore factory braking performance and cooling efficiency, these 380x30mm rotor rings are built for the demands of professional motorsport.
Race-Ready Engineering. Factory-Perfect Fit.
Manufactured in the USA from Girodisc’s proprietary cast iron alloy, each rotor ring is optimized for strength, consistency, and high thermal capacity. The curved vane internal design acts as a centrifugal pump, forcing air through the rotor to maximize cooling and minimize fade. Sold as a pair, the kit includes all new hardware and is designed to bolt directly to your existing Girodisc aluminum hats for a simple, precise installation.
Features
• Size: 380mm x 30mm
• Direct replacement rings for Girodisc Porsche 991 Cup and GT4 Clubsport rear rotors
• Cast from Girodisc proprietary high-carbon iron alloy in the USA
• Curved vane internal geometry for improved airflow and cooling
• Includes all new hardware (drive pins, washers, and bolts)
• Reuses Girodisc aluminum hats
• Not compatible with OEM or non-Girodisc hats
• Sold/priced per pair
Vehicle Fitment
• Porsche 991 GT3 Cup (All Years) – Rear
• Porsche Cayman GT4 Clubsport (981 & 982) – Rear
• Designed for Girodisc two-piece rotor systems
• Will not fit OEM two-piece rotors or other aftermarket hats
Girodisc D2-238 Porsche 991 Cup / GT4 Clubsport Rear Replacement Rings FAQs
Can I reuse my aluminum hats? Yes. These replacement rings bolt directly to your existing Girodisc aluminum hats with the supplied hardware.
Do these fit OEM or factory rotors? No. Girodisc replacement rings are engineered specifically for Girodisc two-piece systems and are not compatible with OEM or other aftermarket hats.
What’s included in the package? Two iron rotor rings (left and right) and a full hardware kit for reassembly.
Are the rotors directional? Yes. Each rotor features directional curved vanes for optimal airflow and cooling efficiency—ensure correct orientation during installation.
Are they sold individually or as a set? The Girodisc D2-238 Rear Replacement Rotor Rings are sold and priced per pair, complete with hardware.
What benefits do these offer over OEM rotors? Girodisc rotors reduce unsprung weight, improve cooling efficiency, and maintain consistent pedal feel and braking balance under the harshest track conditions.
Maintain championship-level braking performance with Girodisc D2-238 380x30mm Rear Replacement Rotor Rings—crafted in the USA to deliver maximum precision, cooling, and reliability for Porsche 991 Cup and GT4 Clubsport race cars.
