GiroDisc A1-078 2-Piece Front Brake Rotors Alfa Romeo 4C Coupe Spider 2013-2020

Vehicle Fitment

• 2013-2020 Alfa Romeo 4C Coupe (Type 960, 1.75T)
• 2014-2020 Alfa Romeo 4C Spider (Type 961, 1.75T)

Fitment Notes

• Front axle only - sold as a pair (2 rotors); for the matching rear axle set, see GiroDisc A2-078
• Direct OE replacement - bolts directly to the factory front hubs and works with OE front calipers and pads without modification
• If only the cast iron rotor rings need replacement (hats are reusable), see GiroDisc D1-078 front replacement rings
• Compatible with all 4C Coupe and Spider variants throughout the production run (2013-2020), including North American market cars
• Factory brake bias and ABS calibration are fully preserved - no recalibration required

Features

• Two-piece floating rotor construction - cast iron rotor ring joined to a 6061-T6 aircraft-specification aluminum hat via a floating drive pin assembly, replacing the single heavy cast iron hat of the OE rotor
• Unsprung and rotational weight reduction - GiroDisc A1-078 rotors are approximately 6.6 kg per rotor versus 6.9 kg for stock, reducing the gyroscopic load, suspension response time, and energy required to accelerate and decelerate the front wheels
• Curved vane disc design - internal vane geometry is developed from racing application to act as a centrifugal pump, actively drawing cooling air through the disc as the rotor spins; significantly improves thermal management over solid or straight-vane designs
• Fully floating mount system - 10 high-strength alloy steel drive pins, manufactured by GiroDisc in the USA to proprietary specifications and cadmium plated for corrosion resistance; pins carry braking torque loads while allowing the rotor ring to float axially and radially relative to the hat
• Anti-noise spring washers on pin mounting - allows thermal growth of the rotor ring without binding against the hat, eliminating the rattle and clicking common to cheaply made floating rotor designs while maintaining true float under load
• Rotor self-centering - the floating design allows the disc to self-center between the brake pads on release, reducing residual drag and uneven pad wear
• Slotted rotor surface - slots sweep away brake dust, gases, and debris from the pad contact face to maintain consistent bite and reduce pad glazing during hard or repeated use
• Proprietary GiroDisc cast iron alloy - poured in the USA and machined in-house at GiroDisc from start to finish; same iron specification used by professional racing organisations
• Once installed, only the cast iron ring needs replacement when worn - the aluminum hat and drive pin hardware are reusable (replacement rings: D1-078)
• Manufactured entirely in the USA

Specifications

• Part Number: A1-078
• Product: 2-Piece Floating Front Brake Rotor Set
• Quantity: 2 rotors (1 pair - full front axle set)
• Rotor Dimensions: 305 x 28 mm
• Rotor Style: Slotted
• Construction: Two-piece floating - cast iron disc ring + 6061-T6 aluminum hat
• Hat Material: 6061-T6 aircraft-specification aluminum (US-sourced)
• Disc Material: Proprietary GiroDisc cast iron (poured and machined in USA)
• Drive Pins: 10 high-strength alloy steel, cadmium plated, per rotor
• Pin Fasteners: Class 12.9 cap screws with hardened washers
• Rotor Weight: approx. 6.6 kg per rotor (vs. approx. 6.9 kg OEM)
• Axle: Front (rear set = A2-078; front replacement rings only = D1-078)
• Installation: Direct bolt-on; no modifications required
• Country of Manufacture: USA

Included Components

• 2x GiroDisc 2-piece floating front brake rotors (1 pair; complete front axle set)
• All required mounting hardware (drive pins, class 12.9 cap screws, hardened washers, anti-noise spring washers)

Product Description

The GiroDisc A1-078 is a pair of two-piece floating front brake rotors engineered as a direct OE replacement for the Alfa Romeo 4C Coupe (2013-2020, Type 960) and 4C Spider (2014-2020, Type 961). They bolt directly onto the factory front hubs and work with the OE front calipers and pads without any modification, spacer, or recalibration - factory brake bias and ABS efficiency are fully preserved. The only change from the OE rotor is that the heavy cast iron hat of the stock one-piece unit is replaced with a CNC-machined 6061-T6 aluminum hat, with the cast iron rotor ring floating on a set of 10 high-strength alloy steel drive pins rather than being rigidly bolted to it.

That floating mount is the core of the GiroDisc system. The drive pins - manufactured in the USA to GiroDisc's proprietary specifications and cadmium plated for corrosion resistance - carry all braking torque loads while allowing the rotor ring to float axially and radially relative to the hat. Anti-noise spring washers at each pin mounting point allow the rotor ring to expand freely with heat without binding against the hat, eliminating the rattle, clicking, and distortion common to cheaper two-piece designs while maintaining true float during operation. This float also allows the disc to self-center between the pads each time the brakes release, reducing residual drag and promoting even pad wear. The slotted disc surface continuously sweeps debris, brake dust, and outgassed compounds away from the pad contact zone to maintain consistent bite and reduce glazing.

The cast iron rotor ring itself is produced from GiroDisc's proprietary iron alloy - poured and machined entirely in-house in the USA to the same specification used by professional racing organisations - and uses a curved internal vane geometry developed in competition to actively pump cooling air through the disc as it rotates. The result is a rotor set that runs cooler, wears the pads more evenly, and carries notably less unsprung and rotational mass than the OE units: approximately 6.6 kg per corner versus 6.9 kg for stock, a gain that is disproportionately valuable given the 4C's sub-900 kg kerb weight and the sensitivity of its suspension geometry to unsprung mass changes. When the rings eventually wear out, only the D1-078 replacement rings need to be purchased - the aluminum hats and hardware are fully reusable. The matching rear set is GiroDisc A2-078.