Toyota GR Supra, BMW 348mm Front Replacement Rings
Restore your braking performance with the Girodisc D1-307 Front Replacement Rings, designed for the Toyota GR Supra and BMW Z4 M40i. These precision-engineered 348mm iron rotor rings are direct replacements for your existing Girodisc two-piece rotors, delivering the same championship-level performance, reduced unsprung weight, and thermal stability that make Girodisc the gold standard for performance braking.
Manufactured from Girodisc’s proprietary high-carbon cast iron alloy and machined in the USA, these rotors are built to handle extreme braking forces and high temperatures without fade. If your original Girodisc rotors have reached their wear limit, these replacement rings let you renew your braking setup while reusing your original Girodisc aluminum hats — saving cost without sacrificing quality.
Features and Benefits
- Direct replacements for Girodisc 348mm front two-piece rotors
- Crafted from proprietary U.S.-poured high-carbon cast iron
- 48 curved directional vanes maximize airflow and cooling
- Lightweight two-piece design reduces unsprung mass
- Includes all new hardware: drive pins, bolts, and washers
- Engineered, machined, and balanced entirely in the USA
Vehicle Fitment
- 2020+ Toyota GR Supra (A90 / A91)
- 2019+ BMW Z4 M40i
- BMW G29 Platform (B58 engine)
These rotor rings are designed exclusively for Girodisc aluminum hats and are not compatible with OEM or other aftermarket hat assemblies.
Why Choose Girodisc
Girodisc performance rotors are trusted by track enthusiasts and professional racers for their ability to handle high thermal loads while maintaining consistent braking feel. The D1-307 front replacement rings deliver the same performance and cooling benefits as a brand-new set — for a fraction of the price. Each ring is optimized for even heat distribution and minimal warping, giving you confident braking under pressure lap after lap.
FAQs
Do these include the aluminum hats?
No. The D1-307 kit includes only the iron rotor rings and a new hardware kit. Your existing Girodisc hats are reused.
Are these compatible with factory rotors?
No. Girodisc rings are engineered exclusively for use with Girodisc hats and cannot be mounted to OEM or other aftermarket assemblies.
Are the rotors directional?
Yes. Each rotor features curved internal vanes that must be installed on the correct side for proper cooling and airflow direction.
What’s included?
Two 348mm front rotor rings (left and right) and a full hardware kit with drive pins, bolts, and washers.
Ready to Upgrade?
When it’s time to refresh your braking system, the Girodisc D1-307 Front Replacement Rings deliver the unmatched cooling, strength, and consistency that define Girodisc. Perfect for both daily driving and track-day abuse, they’ll keep your Toyota GR Supra or BMW Z4 M40i stopping with confidence. Order your set today from Competition Motorsport and get back to peak performance.
