GiroDisc BMW G80/G81 M3, G82/G83 M4 & G87 M2 2-Piece Rear Brake Discs/Rotors Pair

Engineered for enthusiasts who demand consistent braking performance under the most demanding conditions, the GiroDisc 2-Piece Rear Brake Discs are a premium direct replacement upgrade for the factory rear steel brake discs fitted to the BMW G80 M3, G81 M3 Touring, G82 M4, G83 M4 Convertible and G87 M2. Featuring a fully floating two-piece design, these high-performance rear rotors reduce unsprung weight, improve heat management and deliver the durability required for both fast road and track use.

Manufactured in the USA using GiroDisc's proprietary high-carbon iron alloy, these rear brake discs have been developed to provide superior thermal stability and longevity compared to conventional one-piece discs. Combined with GiroDisc's lightweight aluminium hats and motorsport-inspired floating hardware system, they offer an ideal solution for drivers looking to maximise braking consistency and overall vehicle performance.

Key Features

• Direct replacement for factory rear steel brake discs
• Designed for BMW G80/G81 M3, G82/G83 M4 & G87 M2
• GiroDisc part number: A2-282
• Fully floating 2-piece rotor design
• Reduces unsprung and rotating mass
• Proprietary high-carbon iron rotor rings
• Reusable aluminium hats
• 48 curved internal cooling vanes
• Race-proven floating hardware system
• Suitable for road and track use
• Sold as a pair

Lightweight 2-Piece Construction

The GiroDisc rear rotor assembly utilises a lightweight two-piece design consisting of:

• High-carbon iron rotor rings
• CNC-machined 6061-T6 aluminium hats
• High-strength floating hardware

This advanced construction helps reduce:

• Unsprung weight
• Rotational inertia

Resulting in improved suspension response, sharper vehicle dynamics and enhanced braking performance.

Advanced Cooling Performance

Each rear rotor incorporates 48 curved internal vanes, engineered to function as a centrifugal air pump.

This design:

• Draws cool air through the hub
• Increases airflow through the disc
• Reduces operating temperatures
• Improves thermal recovery between braking events

Benefits include:

• Improved resistance to brake fade
• Enhanced braking consistency
• Better heat dissipation during track use
• Increased rotor longevity

Proprietary High-Carbon Iron Rotor Rings

The rotor rings are machined from GiroDisc's own high-carbon iron casting, developed specifically for performance and motorsport applications.

Advantages include:

• Exceptional thermal stability
• Increased crack resistance
• Improved durability under heavy braking
• Longer service life
• Consistent braking performance

This superior metallurgy helps the rotors withstand repeated heat cycles often encountered during track days and spirited driving.

Fully Floating Motorsport Hardware

Each rotor assembly features GiroDisc's race-proven floating system, incorporating:

• High-strength steel drive pins
• Belleville washers
• Spring clips
• Controlled rotor float

This design allows the rotor ring to expand and contract naturally under extreme temperatures while maintaining precise braking feel.

The result is:

• Reduced thermal stress
• Improved durability
• Consistent pedal feedback
• Street-friendly operation without excessive noise

Serviceable Rotor Design

Unlike many conventional brake discs, GiroDisc's two-piece design allows the aluminium hats to be reused when the rotor rings reach the end of their service life.

Replacement ring part number:

• D2-282

This significantly reduces long-term running costs while maintaining the benefits of a premium motorsport braking system.

GiroDisc recommends replacing the rotor rings when:

• Rotor thickness reaches 22mm
• A crack extends to the outer edge of the rotor ring

Premium Manufacturing

All major GiroDisc components are manufactured in-house in Bellingham, Washington using domestically sourced materials.

Construction includes:

• 6061-T6 aluminium hats
• Black anodised finish
• High-strength steel drive pins
• Corrosion-resistant cadmium plating
• Precision-machined rotor rings

This attention to detail ensures exceptional quality, durability and performance.

Product Specifications

• GiroDisc Part Number: A2-282
• Configuration: Fully Floating 2-Piece Rotor
• Rotor Material: Proprietary High-Carbon Iron
• Hat Material: 6061-T6 Aluminium
• Hat Finish: Black Anodised
• Internal Cooling Vanes: 48 Curved Vanes
• Sold As: Pair
• Minimum Recommended Rotor Thickness: 22mm

Compatibility

Suitable for vehicles equipped with factory steel brakes.

BMW G80 M3

• BMW G80 M3
• BMW G80 M3 Competition
• BMW G80 M3 Competition xDrive

BMW G81 M3 Touring

• BMW G81 M3 Touring
• BMW G81 M3 Competition Touring

BMW G82 M4

• BMW G82 M4
• BMW G82 M4 Competition
• BMW G82 M4 Competition xDrive

BMW G83 M4 Convertible

• BMW G83 M4
• BMW G83 M4 Competition

BMW G87 M2

• BMW G87 M2

Not compatible with Carbon Ceramic Brake (CCB) equipped vehicles.

Why Choose GiroDisc?

GiroDisc is trusted by professional race teams and BMW enthusiasts worldwide for:

• Motorsport-proven engineering
• Outstanding cooling performance
• Reduced unsprung weight
• Serviceable two-piece construction
• Exceptional durability under demanding conditions

Why Buy from R44 Performance?

R44 Performance supplies premium BMW braking upgrades trusted by enthusiasts worldwide.

• BMW specialists
• Genuine GiroDisc products
• Fast UK & worldwide shipping
• Expert technical support

Upgrade your braking system with the GiroDisc 2-Piece Rear Brake Discs for the BMW G8X M3, M4 and G87 M2, delivering exceptional cooling, reduced weight and race-inspired performance for road and track use.

Unless explicitly stated otherwise, all products sold by R44 Performance Limited are designated RACE ONLY and are solely for competition or off-road use limited to racing formally sanctioned by a recognized racing organization. Any other use, including recreational off-road use, may violate local, state, and Federal laws. R44 Performance Limited does not implicitly or explicitly confirm the legality of using any products it sells on public roads; that is entirely the responsibility of the consumer.

It is the responsibility of the customer to check with all federal, state local and environmental laws before ordering and installing a product. R44 Performance Limited is not responsible for any fees, fines or costs that a customer may incur as a result of failing to check with federal, state, local or environmental laws before ordering and installing a product.

We get a large number of custom orders and requests everyday, so as a result it is not always possible for us to keep every item in stock at all times in our warehouse. If you require the item urgently please contact our sales team here to check the stock before you make your purchase.

We totally understand if you're not certain a part will be compatible with your car, so we highly recommend contacting us here with your query. Our friendly sales team will then be in touch to confirm if this part is the correct part you are looking for.

All in stock products ship the same day if ordered before 2pm GMT

For out of stock items we will contact you with an estimated wait time if not otherwise specified above.

We offer worldwide shipping on all products. If upon receiving your product you wish to return; we offer a 30-day returns policy. For our in-depth returns information please follow the link. "R44 Returns Policy

All of our products come with a standard warranty of 1-3 years. This is dependant on the type of product however. For more details please see our warranty page here.