Girodisc 316x20 Rear Brake Discs for Subaru Impreza WRX STi (2004–2007)

The Girodisc A2-007 rear brake discs, measuring 316 × 20 mm, improve heat management during repeated braking on the Subaru Impreza WRX STi (2004–2007). Their cast iron rotors and aluminum hubs form a floating assembly designed to handle thermal stresses 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 rear axle of compatible vehicles in the configuration shown below. They retain the compatible calipers; any required spacers and brake pad specifications must be followed.

The curved internal cooling fins channel air through the rotor to dissipate heat during repeated braking. The floating mounting limits stresses caused by differences in thermal expansion between the rotor and the housing and helps the rotor center itself between the brake pads, maintaining consistent contact under heat.

The hub is made of 6061-T6 aluminum. The high-strength steel drive pins are cadmium-plated to resist corrosion. They are secured by Class 12.9 bolts and hardened washers. Spring washers minimize cold-mounting noise while allowing the necessary compression for the floating mount.

New pads must be installed with new discs or tracks. Their shape and compound must be compatible with the mounting, the cast iron, and the intended use; comply with the specific requirements for this part number and perform the prescribed break-in procedure.

Specifications for Girodisc A2-007 rotors for compatible vehicles

• Brand: Girodisc
• PartNumber: A2-007
• Position: rear
• Sizes (diameter × thickness): 316 × 20 mm
• Vehicles and models: Subaru Impreza WRX STi (2004–2007)
• Braking surface material: high-resistance cast steel
• Packaging: Pair of complete rotors, one left and one right with disc bells.
• Hub: 6061-T6 aluminum
• Construction: two-piece floating mounting design
• Catalog part number: D2-007. Verify compatibility with the caliper generation before replacement.
• Internal ventilation: directional curved fins
• Minimum thickness: 18 mm
• Overall height: 68 mm
• Original rotor diameter: 316 mm
• Weight / weight reduction: Comparison stated in the manufacturer’s specifications: approximately 4.99 kg per disc versus 8.16 kg for the original, for a weight savings of 3.18 kg per disc (6.35 kg per pair).
• Manufacturing of main components: United States

Vehicles compatible with Girodisc part number A2-007

• Subaru Impreza WRX STi (2004–2007)

• Subaru Impreza WRX STi (2004–2007): Rear brake bracket brackets must be modified.
• Subaru Impreza WRX STi (2004–2007): The metal brake pads on the original brake pads and certain aftermarket brake pads require adjustment to clear the brake disc mounting while retaining the parking brake. It is essential to follow the instructions and use pre-prepared brake pads when available.

Each application is specific to its brake system, calipers, and any requirements for brake pads or spacers. Check these requirements before ordering.

Girodisc A2-007 Mounting Requirements

• Subaru Impreza WRX STi (2004–2007): Rear brake pad brackets must be modified.
• Subaru Impreza WRX STi (2004–2007): The metal brackets on the original equipment and certain aftermarket brake pads require adjustment to clear the brake disc mounting while retaining the parking brake. It is essential to follow the instructions and use pre-machined brake pads when available.

Brake Pads and Braking System for Compatible Vehicles

Choose brake pads whose shape is compatible with the calipers, track, and/or A2-007 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 a mounting compatible with the original hydraulic system.

Maintenance of the Girodisc mounting on compatible vehicles

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 components, and the mounting instructions; this number does not constitute a guaranteed service life. Use a new mounting component each time you replace the pads.

FAQ — Girodisc A2-007 for compatible vehicles

What are the sizes of the A2-007 discs for my vehicle? The part number shown measures 316 × 20 mm and is mounted on the rear 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 are shipped with their hubs.

Do I need to replace the brake pads on my vehicle?Yes. Always install new brake pads with new brake discs or new braking surfaces. Use a compound suitable for cast iron and your intended use. The metal brackets on the original brake pads and on some aftermarket pads require adjustment to clear the brake disc mounting while maintaining the parking brake. It is essential to follow the instructions and use pre-prepared pads when available.

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 from 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.

PDF Documents for Mounting 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.

Key Features of Girodisc A2-007 Bowl Brake Discs

• 316 × 20 mm size for rear braking on compatible vehicles.
• 6061-T6 aluminum bowl and floating mount to manage thermal stresses.
• Internal ventilation via curved fins to dissipate heat.
• Replaceable brake pads to maintain a two-piece mounting.
• Left/right pair identified for mounting.
• Aluminum rotors help reduce unsprung and rotating mass compared to a comparable one-piece cast iron disc.