Two-Piece Front Brake Rotors, 911 GT3 (991)
380 mm floating two-piece rotors on aluminium hats, using curved internal vanes that pump cooling air outward under rotation.
Brakes In production confidence: medium
Manufacturing
| Manufacturer | GiroDisc |
|---|---|
| Origin | 🇺🇸 United States Manufactured here Iron poured and machined in house at GiroDisc; hats from US-sourced 6061-T6. |
| Process | Cast |
| Additively manufactured | No |
| Material | Cast Iron, 6061-T6 Aluminium |
| Construction | Cast iron disc on a 6061-T6 aluminium hat, floating on alloy steel drive pins. |
| Notes | Iron poured and machined in house. The curved vane pattern is directional, so left and right rotors are not interchangeable. |
Published figures
| Basis | Published by the manufacturer; not independently verified. |
|---|---|
| Notes | Claimed benefit is reduced unsprung mass and better cooling; no absolute figures published. Bolts to OEM calipers and pads. |
Fitment
| 991 | GT3, GT3 RS |
|---|
Sources
- Porsche 991 GT3 Front Rotors — A1-146 — GiroDisc, accessed 2026-08-17