BMW F8X Rear Brake Upgrade from XC3 Engineering: AP Racing CP9449 380mm Guide
The BMW F87 M2, F80 M3 and F82 M4 are highly capable performance cars, but as power, tyre grip and track use increase, the braking system often becomes one of the next areas to upgrade.
For cars already running an upgraded front brake setup, a rear brake upgrade can improve consistency, increase brake pad choice and create a more complete braking package.
The XC3 Engineering BMW F8X rear brake upgrade combines AP Racing CP9449 Pro 5000 R four-piston calipers with Genuine BMW 2NH 380mm x 28mm rear brake discs and XC3 precision-engineered mounting hardware.
Why Upgrade the Rear Brakes on a BMW F8X?
For most road cars, the standard rear brakes are perfectly adequate. However, the demands change when an F8X BMW is used for regular track days or motorsport.
A rear brake upgrade can provide:
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Increased brake pad choice
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Improved consistency during repeated hard braking
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Better compatibility with upgraded front brake systems
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Access to dedicated track and motorsport compounds
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A complete AP Racing braking setup front and rear
The XC3 kit is aimed particularly at owners already running, or planning to run, an upgraded front big brake kit.
AP Racing CP9449 Pro 5000 R Calipers
At the heart of the kit is the AP Racing CP9449 Pro 5000 R four-piston caliper.
Developed for high-performance rear braking applications, the CP9449 offers a lightweight motorsport-derived design and access to a wide range of performance brake pads.
The kit is available with:
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Grey anodised AP Racing CP9449 calipers
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Nickel-plated AP Racing CP9449 calipers
This makes it ideal for pairing with XC3 Engineering AP Racing front brake kits.
Genuine BMW 380mm Rear Brake Discs
The XC3 rear brake upgrade uses Genuine BMW 2NH 380mm x 28mm rear brake discs.
Using a Genuine BMW disc provides a large rear braking surface while keeping replacement consumables readily available.
For track cars, this is important. Brake kit ownership is not only about the initial purchase price; replacement discs and pads contribute significantly to long-term running costs.
XC3 Precision-Engineered Caliper Brackets
The AP Racing calipers are mounted using XC3 Engineering brackets CNC machined from 6082-T6 aluminium.
Each bracket is designed specifically to correctly position the CP9449 caliper with the BMW 380mm disc.
Correct caliper alignment, pad sweep and disc positioning are critical in any brake conversion, which is why XC3 develops the mounting hardware as a chassis-specific engineered component.
XC3-manufactured components are also covered by our Lifetime Warranty.
What's Included?
Depending on the configuration selected, the XC3 BMW F8X rear brake upgrade includes:
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2x AP Racing CP9449 Pro 5000 R four-piston calipers
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2x XC3 CNC-machined 6082-T6 aluminium caliper brackets
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2x Genuine BMW 2NH 380mm x 28mm rear brake discs
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F8X-specific braided brake lines
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High-tensile mounting hardware
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500ml Motul RBF 660 brake fluid
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Choice of performance brake pads
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Choice of anodised or nickel-plated AP Racing calipers
The kit is also available without brake pads, making it ideal for customers who already have a preferred pad compound or want to source their pads separately.
Choosing the Right Brake Pad
One of the biggest advantages of using an AP Racing motorsport caliper is the range of brake pad compounds available.
Ferodo DS2500
A good choice for fast-road cars that occasionally see track use.
Pagid RSL29
A popular option for regular track days, offering good consistency, modulation and longevity.
Ferodo DSUNO
A more track-focused compound designed for higher temperatures and demanding use.
PFC 08
Well suited to longer track sessions where consistency and pad life are priorities.
For most track-focused F8X builds, Pagid RSL29 or Ferodo DSUNO provide an excellent starting point.
Brake pad choice should always be considered alongside the front braking setup.
If you already know which pad compound you want to run, the kit can also be supplied without pads.
BMW F80 M3 Rear Brake Upgrade
For BMW F80 M3 owners, the XC3 Engineering AP Racing rear brake kit provides a route to a four-piston motorsport rear caliper setup.
It is particularly suited to F80 M3 track cars already running an upgraded front brake system.
BMW F82 M4 Rear Brake Upgrade
The same applies to the BMW F82 M4.
As grip, power and braking demands increase, upgrading the rear brakes allows the braking system to develop alongside the rest of the car.
BMW F87 M2 Rear Brake Upgrade
The XC3 kit is also suitable for the BMW F87 M2 and M2 Competition.
For track-focused builds, pairing an upgraded front big brake kit with the AP Racing CP9449 rear setup creates a more complete braking package designed around repeated high-performance use.
Is the XC3 Rear Brake Kit Suitable for Track Days?
Yes.
The XC3 Engineering rear brake upgrade is developed for fast road, track day and motorsport use.
For regular track use, brake pad choice remains particularly important. A road car completing occasional track days has very different requirements from an F80 M3 running repeated 20-minute sessions on high-grip tyres.
XC3 Engineering can help customers select the most suitable front and rear pad combination for their car and intended use.
Will the 380mm Rear Brake Kit Fit My Wheels?
The XC3 Engineering 380mm rear brake upgrade is designed to work with all commonly used track-focused alloy wheel setups, as well as compatible OEM BMW wheel configurations.
This makes the kit suitable for everything from road-going F8X cars on factory wheels through to dedicated track builds running motorsport-focused alloy wheels.
As wheel designs can vary in spoke profile, offset and internal barrel clearance, we still recommend confirming clearance before ordering if you are running an unusual wheel specification.
If you're unsure, contact XC3 Engineering with your wheel make, model, size and offset and we'll be happy to advise.
Designed and Manufactured by XC3 Engineering
The XC3 BMW F8X rear brake upgrade brings together:
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AP Racing motorsport calipers
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Genuine BMW 380mm brake discs
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XC3 precision-engineered mounting hardware
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Performance brake pad options
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F8X-specific brake lines and hardware
The result is a complete rear brake upgrade for serious BMW F87 M2, F80 M3 and F82 M4 builds.
XC3-manufactured components are designed and manufactured in the UK and backed by our Lifetime Warranty.
Upgrade Your BMW F8X Rear Brakes
If your F8X already has upgraded tyres, suspension, power or a serious front braking setup, the rear brakes are a logical next step.
The XC3 Engineering BMW F8X AP Racing CP9449 380mm Rear Brake Upgrade combines proven AP Racing hardware, Genuine BMW brake discs and XC3 precision-engineered components into one complete package.
Compatible with:
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BMW M2 F87
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BMW M2 F87 Competition
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BMW M3 F80
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BMW M3 F80 Competition
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BMW M4 F82
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BMW M4 F82 Competition
The kit is available with a choice of performance brake pads or without pads for customers who already have a preferred compound.
View the BMW F8X AP Racing Rear Brake Upgrade from XC3 Engineering and configure your caliper finish and brake pad option.