AP Racing CP9449 Pro 5000R 378mm Rear Brake Kit – BMW E9X M3

AP Racing CP9449 Pro 5000R 378mm Rear Brake Kit – BMW E9X M3The AP Racing CP9449 Pro 5000R Rear Brake Kit (378x32mm) for the BMW E9X M3 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 upgrade, the system provides a substantial increase in thermal management and durability over the factory rear braking setup. Using

The AP Racing CP9449 Pro 5000R Rear Brake Kit (378x32mm) for the BMW E9X M3 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 upgrade, the system provides a substantial increase in thermal management and durability over the factory rear braking setup.

Using large 378x32mm two-piece rear discs, lightweight aluminium bells and precision-engineered mounting brackets, the system improves rear braking stability and heat dissipation during repeated heavy braking. The increased rotor size improves thermal capacity during prolonged high-temperature use, helping maintain consistent braking performance throughout demanding track 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 performance, durability and consistency. Several customers previously running 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.

Designed as a direct bolt-on upgrade, the kit mounts to the factory rear uprights using supplied brackets and hardware while delivering genuine motorsport braking performance with excellent fitment and reliability.

Further information below.