BMW M2 / M3 / M4 F8X BTCC Brake Conversion Kit – Caliper Carriers & Rotor Bells for AP Racing CP9660 | XC3 Engineering

XC3 Engineering BTCC Brake Conversion Kit – BMW M2 / M3 / M4 F8x

Upgrade your BMW F8x braking system with the XC3 Engineering BTCC Brake Conversion Kit, designed for use with AP Racing 5000R CP9660 calipers and 368 × 36 mm BTCC-spec brake rotors.

This kit provides the key vehicle-specific hardware required to adapt the AP Racing and BTCC components to the standard BMW F8x front hubs.

Supplied with precision CNC-machined caliper carriers and lightweight rotor bells, the kit is designed to provide accurate caliper positioning, strong structural support and reliable performance under demanding road and track use.

Why Choose the XC3 BTCC Brake Conversion Kit?

A high-performance brake conversion relies on accurate component positioning and a strong mounting interface.

The XC3 kit is designed to provide the foundation for a serious front brake setup using proven motorsport components.

Potential benefits include:

• Enables AP Racing CP9660 caliper fitment
• Designed for 368 × 36 mm BTCC-spec rotors
• Accurate caliper and rotor positioning
• Strong lightweight construction
• Suitable for high-temperature track use
• Ideal for clubsport and trackday builds
• Compatible with OEM F8x front hubs
• Designed and manufactured in the UK

What's Included?

The XC3 Engineering BTCC Brake Conversion Kit includes:

• XC3 Custom Caliper Carriers
• XC3 Custom Rotor Bells
• Caliper carrier mounting hardware

AP Racing CP9660 calipers and BTCC rotors are not included unless otherwise stated.

Designed for AP Racing 5000R CP9660 Calipers

The caliper carriers are specifically engineered around the AP Racing 5000R CP9660 caliper.

Accurate caliper positioning is critical to ensure:

• Correct pad sweep
• Proper rotor alignment
• Consistent braking performance
• Reliable operation under load

Designed for 368 × 36 mm BTCC Rotors

The rotor bells are engineered to work with compatible 368 × 36 mm BTCC-spec brake rotors.

These motorsport-derived rotors provide a strong foundation for high-capacity braking systems where heat management and repeatability are important.

Precision CNC Machined

The caliper carriers and rotor bells are precision CNC machined to motorsport-focused tolerances.

This helps provide:

• Accurate fitment
• Consistent component positioning
• Strong structural integrity
• Repeatable installation

6082-T6 Aluminium Construction

The XC3 components are manufactured from 6082-T6 aluminium.

This provides an effective balance of:

• Strength
• Rigidity
• Low weight
• Durability

This material is well suited to motorsport and performance braking applications.

Lightweight Rotor Bells

The rotor bells are designed to provide a strong but lightweight interface between the hub and brake rotor.

Reducing unnecessary rotating and unsprung mass can be beneficial in performance applications, while maintaining the strength required for repeated high-energy braking.

Black Anodised Finish

The components are finished in black anodising for:

• Improved corrosion resistance
• Increased surface durability
• Long-term appearance

CNC Engraved

XC3 branding is CNC engraved into the components for a clean and durable finish.

Caliper Bracket Hardware Included

The kit includes the relevant caliper carrier mounting hardware.

This provides a secure mounting solution for the conversion and helps simplify installation.

Motorsport-Derived Braking Foundation

Using BTCC-derived rotors with AP Racing CP9660 calipers provides the basis for a high-capacity braking setup aimed at demanding use.

Potential advantages of the completed system include:

• Improved braking consistency
• Better heat capacity
• Greater resistance to fade
• Improved repeatability
• Increased confidence under hard braking

Cost-Effective Performance

One of the attractions of this conversion is the ability to use proven motorsport components while retaining the standard BMW front hubs.

This can offer strong performance value for track-focused builds.

Ideal for Clubsport & Trackday Builds

This conversion is particularly suited to:

• F87 M2 track builds
• F87 M2 Competition track builds
• F80 M3 clubsport setups
• F82 M4 trackday cars
• Time attack-inspired builds
• High-performance road cars

Supporting Components Matter

The carrier and bell kit forms only part of the complete braking system.

For serious track use, the final setup should also consider:

• AP Racing CP9660 calipers
• 368 × 36 mm BTCC rotors
• Appropriate brake pads
• AP Racing rotor bobbins
• Braided brake lines
• High-temperature brake fluid
• Brake cooling
• Suitable tyres

Designed & Manufactured in the UK

XC3 Engineering designs and manufactures the conversion components in the UK.

The kit is developed specifically around the BMW F8x front hub and AP Racing CP9660 / BTCC rotor combination.

Direct Fitment to OEM Front Hubs

The kit is designed for BMW F8x models using standard OEM front hubs.

No alternative hub conversion is required.

Lifetime Warranty

XC3 Engineering backs this product with a lifetime warranty.

This provides additional confidence in the durability and structural integrity of the components.

Warranty terms and conditions should be checked before purchase.

Professional Installation Required

Professional installation is strongly recommended.

Brake conversions are safety-critical and should be fitted by a suitably experienced technician.

Installation checks should include:

• Caliper alignment
• Rotor alignment
• Hardware torque
• Brake hose clearance
• Wheel clearance
• Pad position
• System bleeding

Vehicle Fitment

BMW F8x

Compatible models:

• BMW F87 M2
• BMW F87 M2 Competition
• BMW F80 M3
• BMW F82 M4

Designed for:

• Standard OEM front hubs
• AP Racing CP9660 calipers
• Compatible 368 × 36 mm BTCC rotors

Related Components

Compatible supporting parts include:

• Replacement 368 × 36 mm ex-BTCC rotors
• AP Racing rotor bobbins
• AP Racing CP9660 calipers
• Performance brake pads
• Braided brake lines
• High-temperature brake fluid

A complete bolt-on F8x BTCC brake kit is also available separately.

Explore More BMW F8x Braking

BMW F87 M2 – Explore braking, suspension and performance upgrades for the BMW F87 M2.

BMW F87 M2 Competition – Explore braking, suspension and performance upgrades for the BMW F87 M2 Competition.

BMW F80 M3 – Explore braking, suspension and performance upgrades for the BMW F80 M3.

BMW F82 M4 – Explore braking, suspension and performance upgrades for the BMW F82 M4.

XC3 Engineering – Browse XC3 braking, chassis and motorsport components.

Brakes – Explore performance brake components and upgrades.

Brake Discs – Browse performance rotors and brake disc options.