Girodisc A1-091 front brake discs, measuring 380 × 32 mm, optimize consistent braking performance during spirited driving in the Ford Mustang GT500 (S197) (2013–2014). Their cast-iron rotors and aluminum hubs form a floating assembly designed to manage thermal stress and facilitate rotor replacement due to wear. Sold as a pair, including one left-side and one right-side rotor.
These rotors are intended for the front axle of compatible vehicles in the configuration shown below. They retain the compatible caliper mounting; any required spacers and pad specifications must be followed.
The cast iron track and floating connection allow the disc to accommodate differences in thermal expansion between its two parts and to center itself between the brake pads. This construction also makes it easier to replace the tracks when they are worn.
The hub is made of 6061-T6 aluminum.
New pads must be installed with new discs or new tracks. Their shape and compound must match the mounting configuration, the cast iron, and the intended use; comply with the specific requirements for this part number and perform the prescribed break-in procedure.
Each application is subject to its specific brake system configuration, calipers, and any requirements for brake pads or spacers. Please verify these requirements before ordering.
Choose brake pads whose shape is compatible with the calipers, track, and/or the A1-091 rotor, and whose compound is suitable for sport driving or track use. The Endless, pagid Racing, or Ferodo Racing ranges may be considered after verifying the appropriate part number.
For intensive use, we recommend compatible aviation-grade hoses and high-performance brake fluid that meets the vehicle’s specifications, along with proper bleeding and fluid replacement. This recommendation complements the mounting, which is compatible with the original hydraulic system.
Replacing the pads alone helps keep the controlled rotors in good condition. Reusing a rotor for up to three pad replacements is subject to inspection of its condition, its mounting hardware, and the mounting instructions; this number does not constitute a guaranteed service life. Use new mounting hardware with each pad replacement.
What are the sizes of the A1-091 discs for my vehicle? The part number shown measures 380 × 32 mm and is mounted on the front axle. The diameter alone is not sufficient: also check the brake system type and mounting requirements.
Is the product sold in pairs? Yes. It includes a left and a right disc for the same axle. Both discs come with their disc bells.
Do I need to replace my vehicle’s brake pads?Yes. Always install new brake pads with new rotors or new braking surfaces. Their shape and compound must be compatible with the A1-091 track and/or rotor and with the calipers. Then break in the rotors and pads according to the prescribed procedures.
How do I identify the left and right sides? Girodisc rotors come with a label attached to each rotor: LEFT for the left side and RIGHT for the right side, as viewed in the direction of travel. On a left-hand-drive vehicle, “LEFT” corresponds to the driver’s side and “RIGHT” to the passenger side. Follow these labels and the instructions. On models with curved internal fins, the rolling direction depends on this internal ventilation; the surface grooves alone are not sufficient to determine the side.
How do I break in this mounting on my vehicle? Follow the Girodisc procedure and the brake pad manufacturer’s instructions to build up an even transfer ply. The PDF documents below detail installation and break-in.
We have included two PDF documents below: an instruction manual for installing and breaking in the discs, and an instruction manual for installing new tracks on existing bowls. Consult the document that applies to your specific task before you begin.
