AP Racing CP9449 Pro 5000R 378mm Rear Brake Kit – BMW G8X M2, M3 & M4

The AP Racing Pro 5000R Rear Big Brake Kit (378x32mm) for the BMW G8X platform has been developed to complement high-performance front brake systems and deliver improved rear braking balance, heat capacity and braking consistency for fast road, track day and motorsport applications. Designed as a direct bolt-on solution, the kit provides a substantial increase in thermal management and durability over the factory rear braking system.

Using large 378x32mm two-piece floating rear discs, lightweight aluminium bells and precision-engineered mounting brackets, the system improves heat dissipation and rear braking stability during repeated heavy braking. The increased rotor mass and floating disc design help reduce temperature build-up under prolonged track use, maintaining more consistent braking performance throughout demanding sessions.

This kit utilises high-quality aftermarket two-piece discs/rotors, providing a durable and cost-effective solution for track-focused vehicles. At Clubsport Garage we have extensively tested these rotor assemblies on our own F87 M2 Competition track car with excellent results in terms of consistency, durability and overall performance. Several customers who previously ran AP Racing rotor assemblies have also moved to this setup and reported similarly positive feedback, making them an attractive option for reducing long-term running costs without sacrificing braking performance.

AP Racing Pro 5000R calipers do not utilise dust seals. This motorsport-focused design allows reliable operation at significantly higher temperatures than conventional road calipers. Vehicles used regularly on the road may require more frequent inspection and cleaning, particularly during harsh weather conditions.

An optional anti-rattle pad retention spring kit is available separately for customers wanting to minimise brake pad movement and reduce unwanted noise during everyday driving.

The kit is also available with an optional Belfe electronic handbrake conversion, allowing customers to retain electronic parking brake functionality. If the Belfe kit is not selected, the vehicle will lose parking brake functionality, which may not be a concern for dedicated track or race vehicles.

Further information below.