Girodisc 390x34mm Front Rings
Service your performance braking system with Girodisc D1-163 390x34mm front replacement rings. These precision-machined components bolt directly to your existing Girodisc aluminum hats using the supplied floating hardware kit. Each ring is crafted from Girodisc’s proprietary high-carbon cast iron alloy to ensure exceptional heat dissipation, consistent friction characteristics, and long-term reliability under heavy braking loads.
Vehicle Fitment
Compatible with:
• Custom and motorsport applications using Girodisc 390x34mm two-piece front rotors
• Commonly fitted to upgraded systems on Porsche, BMW, and Audi track platforms using large six-piston calipers
Note: Designed exclusively for Girodisc 390x34mm two-piece front rotor systems. Verify hat bolt pattern and offset before installation.
Features
• Sold as a left/right pair with complete floating hardware kit
• Direct replacements for Girodisc 390x34mm two-piece front rotors
• CNC-machined from high-carbon cast iron for optimal thermal stability
• Directional curved vanes channel airflow for maximum cooling
• Maintains proper brake bias and ABS calibration
• Precision-balanced to prevent vibration or pulsation
• Designed exclusively for Girodisc aluminum hats
Specifications
• Diameter: 390 mm
• Thickness: 34 mm
• Position: Front
• Material: High-carbon cast iron
• Mount type: Floating two-piece system
• Includes: Two rotor rings and new hardware kit
• Sold/priced per pair
Girodisc D1-163 Front Replacement Ring FAQs
What cars typically use this 390x34mm rotor size? This ring size is common on large six-piston BBK setups from Brembo, AP Racing, and StopTech used on Porsche 991, BMW F8X, and Audi RS applications when fitted with Girodisc hats.
Can these be installed on non-Girodisc hats? No. The mounting pattern and float hardware are specific to Girodisc aluminum hats. Using other hats may cause clearance or balance issues.
What torque should I apply to the floating hardware? Torque each bolt to 12 ft-lbs (16 Nm) with blue Loctite. Recheck after the first heat cycle to ensure hardware seating.
How do I know when it’s time to replace the rings? Replace when rotor thickness reaches the minimum spec or if radial cracking extends beyond 70% of the face slot length — whichever occurs first.
Girodisc D1-163 390x34mm front replacement rings deliver precision, durability, and race-proven performance for drivers demanding the highest level of stopping power and thermal control.
