# Girodisc 305x28 Front Brake Discs for Alfa Romeo 4C (2014–2020)

> Pair of Girodisc front disks, 305 × 28 mm, part no.: A1-078. High-performance floating brake discs on an aluminum hub for the Alfa Romeo 4C (2014–2020).

- URL: https://www.gt2i.ch/en/brake-disk-for-bell/224598-girodisc-305x28-front-brake-discs-for-alfa-romeo-4c-20142020-3666618859231.html
- Reference: GIRO-A1-078
- Price: CHF 1,206.46
- Brand: GIRODISC
- Availability: out of stock

## Description

The Girodisc A1-078 front brake discs, measuring 305 × 28 mm, optimize consistent braking performance during spirited driving in the Alfa Romeo 4C (2014–2020). Their cast-iron rotors and aluminum hubs form a floating assembly designed to manage thermal stresses and facilitate rotor replacement due to wear. Sold as a pair, including one left-hand and one right-hand rotor.
These discs are intended for the front axle of compatible vehicles in the configuration indicated below. They retain the calipers from the compatible mounting; 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 minimizes stresses caused by thermal expansion differences 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-trimmed to resist corrosion. They are secured with 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 A1-078 rotors for compatible vehicles
Brand: Girodisc
PartNumber: A1-078
Position: front
Sizes (diameter × thickness): 305 × 28 mm
Vehicles and models: Alfa Romeo 4C (2014–2020)
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: D1-078. Verify compatibility with the caliper generation before replacement.
Internal ventilation: directional curved fins
Minimum thickness: 26 mm
Original rotor diameter: 305 mm
Manufacturing of main components: United States
Vehicles compatible with Girodisc part number A1-078
Alfa Romeo 4C (2014–2020)
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.
Brake pads and braking systems for compatible vehicles
Select brake pads whose shape is compatible with the calipers, track, and/or A1-078 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 flexible hoses and high-performance brake fluid that meets the vehicle’s specifications, along with proper bleeding and fluid replacement. This recommendation complements a mounting that is 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 A1-078 for Compatible Vehicles
What are the sizes of the A1-078 discs for my vehicle? The part number shown measures 305 × 28 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 the brake pads on my vehicle?Yes. Always install new brake pads with new rotors or new braking surfaces. Their shape and compound must be compatible with the A1-078 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.
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 A1-078 Bowl Brake Discs
305 × 28 mm size for front braking on compatible vehicles.
6061-T6 aluminum rotor 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.

## Features

- Product type: Brake disc on a Bol
- Diameter in mm: 305
- Position: Avant
- Thickness: 28