MMX Crank hub capture plate | BMW S55 | N55
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MMX Crank Hub Capture Plate – BMW N55 & S55
Add an extra layer of protection to your BMW N55 or S55 engine with the MMX Crank Hub Capture Plate.
Designed to fit over and secure the head of the crank bolt, the MMX Capture Plate physically prevents the bolt from rotating or loosening as a result of engine vibration and harmonics.
It can be fitted with either the factory BMW crank hub or the MMX one-piece crank hub, making it a useful standalone reliability upgrade or an ideal addition to a full crank hub replacement.
For standard, tuned and performance-focused N55 and S55 applications, the MMX Capture Plate provides a simple mechanical safeguard against crank bolt movement.
Why Fit a Crank Hub Capture Plate?
The N55 and S55 crank hub system relies on the crank bolt remaining correctly tightened.
If the bolt begins to loosen, the clamping force acting on the crank hub assembly can be reduced.
This can allow the timing system to move out of its intended position, potentially leading to serious engine damage.
The MMX Capture Plate is designed to prevent this by physically surrounding the crank bolt head and stopping it from rotating.
Key Features
- MMX Crank Hub Capture Plate
- Designed for BMW N55 and S55 engines
- Helps prevent crank bolt loosening
- Completely surrounds the crank bolt head
- Physically prevents crank bolt rotation
- Suitable with the OEM BMW crank hub
- Compatible with MMX single-piece crank hub
- Compatible with MMX 4-pinned crank hub
- Single-piece billet design
- Machined from T-6061 billet aluminium
- Gloss-black anodised finish
- Elongated mounting slots for accurate positioning
- Can be installed with the engine remaining in the vehicle
- Ideal for standard and tuned engines
- Complete fitting kit supplied
- MMX part number MMR20-1002
Prevents Crank Bolt Rotation
The main purpose of the MMX Capture Plate is straightforward.
Once installed, the plate completely surrounds the head of the crank bolt.
This creates a physical barrier that prevents the bolt from rotating.
Rather than relying solely on bolt torque and friction, the capture plate provides a mechanical form of retention.
Helps Protect Engine Timing
The crank hub plays a critical role in maintaining the relationship between the crankshaft and camshaft timing.
If crank bolt clamping force is lost, the hub assembly can become more vulnerable to movement.
Any significant timing shift can potentially result in:
- Incorrect cam timing
- Engine fault codes
- Poor running
- Loss of performance
- Piston-to-valve contact in severe cases
- Expensive engine repairs
The MMX Capture Plate is designed to reduce the likelihood of crank bolt loosening contributing to this type of failure.
T-6061 Billet Aluminium Construction
MMX machines the Capture Plate from T-6061 billet aluminium.
This provides a strong but lightweight component capable of securely retaining the crank bolt head.
The billet construction also allows the plate to be manufactured with the accuracy required for correct positioning around the crank hub assembly.
Gloss-Black Anodised Finish
The Capture Plate is finished in MMX's gloss-black anodised finish.
This provides:
- Surface protection
- Corrosion resistance
- Durable appearance
- OEM-style finish
Although the component is primarily functional, the finish gives it the same premium appearance as other MMX engine hardware.
Elongated Mounting Slots
The MMX Capture Plate uses elongated mounting slots.
These provide additional positioning tolerance during installation, helping the plate sit correctly around the crank bolt head before being secured.
Correct positioning is important because the plate must physically block the crank bolt from rotating.
Works with the Factory Crank Hub
The MMX Capture Plate does not require the MMX crank hub to be fitted.
It can be installed with the original BMW crank hub.
This makes it a useful starting point for owners who:
- Have a standard engine
- Aren't currently replacing the crank hub
- Want additional crank bolt security
- Want a more affordable preventative upgrade
MMX positions the Capture Plate as a useful first step for standard cars and vehicles not subjected to particularly demanding track use.
Works with the MMX Single-Piece Crank Hub
The Capture Plate can also be combined with the MMX Single-Piece Crank Hub.
The two components address different potential areas of movement.
The one-piece crank hub is designed to prevent the friction elements within the factory multi-piece hub arrangement from slipping.
The Capture Plate is designed to prevent the crank bolt itself from rotating loose.
Combining both provides a more comprehensive crank hub reliability upgrade.
Compatible with the MMX 4-Pinned Crank Hub
For higher-output builds, the Capture Plate can also be used alongside the MMX 4-Pinned Single-Piece Crank Hub.
That system mechanically locates the hub to the crankshaft using four dowels, while the Capture Plate adds physical crank bolt retention.
For highly modified or heavily track-driven N55 and S55 engines, this represents MMX's most comprehensive crank hub arrangement.
Capture Plate vs Crank Hub Upgrade
The MMX Capture Plate and a replacement crank hub do not perform exactly the same job.
Capture Plate:
- Helps prevent crank bolt loosening
- Retains the existing crank hub
- Lower-cost upgrade
- Less invasive installation
- Suitable as an additional safeguard
Single-Piece Crank Hub:
- Replaces the factory multi-piece hub
- Removes the internal friction interface between hub components
- More comprehensive repair
- Requires significantly more involved installation
For owners wanting maximum protection, combining the two is the stronger solution.
Ideal for Standard Cars
The MMX Capture Plate can be a useful reliability upgrade even on a completely standard N55 or S55 engine.
No additional power is required for engine vibration and harmonics to act on the crank bolt.
For owners who want additional peace of mind without carrying out a complete crank hub replacement, the plate provides a straightforward mechanical safeguard.
Suitable for Tuned Cars
The Capture Plate can also be used on tuned vehicles.
This includes cars with:
- Stage 1 ECU tuning
- Increased boost
- Intake upgrades
- Performance exhausts
- Intercooler upgrades
- Fast-road modifications
For more highly modified or aggressively driven engines, MMX recommends combining the Capture Plate with an upgraded crank hub rather than relying on the plate alone.
Can Be Installed with the Engine In Situ
A major advantage of the MMX Capture Plate is that installation can be carried out with the engine remaining in the vehicle.
MMX states that the radiator needs to be dropped to provide adequate access, but complete engine removal is not required.
This makes the Capture Plate considerably less involved to install than a complete crank hub replacement.
Professional Installation Recommended
Although the plate itself is mechanically simple, access to the crank hub area is restricted.
Professional installation by a BMW specialist is therefore recommended.
Correct fitting is particularly important to ensure:
- Proper alignment around the crank bolt
- Secure mounting
- Correct crank bolt torque where disturbed
- No interference with surrounding components
BMW F20 / F21 M135i
The MMX Capture Plate is compatible with applicable N55-powered BMW F20 and F21 M135i models.
For standard or tuned M135i builds, it provides an additional safeguard against crank bolt movement.
BMW F22 / F23 M235i
The N55-powered BMW F22 M235i Coupe and F23 M235i Convertible are also supported.
It can be fitted with the factory crank hub or combined with an upgraded MMX crank hub later.
BMW F30 / F31 335i
The MMX Capture Plate is suitable for applicable N55-powered BMW F30 and F31 335i models.
For tuned road cars, it offers a relatively straightforward way to add crank bolt security.
BMW F32 / F33 435i
The BMW F32 435i Coupe and F33 435i Convertible with the N55 engine are also compatible.
BMW F87 M2
The original BMW F87 M2 uses the N55 engine and is included in MMX's application range.
The Capture Plate can be fitted as a standalone upgrade or alongside the MMX single-piece crank hub.
BMW F87 M2 Competition
The BMW F87 M2 Competition uses the S55 engine and is also supported.
For modified M2 Competition builds, the Capture Plate provides additional crank bolt security.
BMW F80 M3
The S55-powered BMW F80 M3 is compatible with the MMX Capture Plate.
It is particularly relevant for performance-focused and tuned M3 applications.
BMW F82 M4
The BMW F82 M4 is also supported.
The Capture Plate can be used with the original crank hub or MMX replacement hub.
BMW F83 M4 Convertible
The S55-powered BMW F83 M4 Convertible is also compatible with the MMX Capture Plate.
Compatibility
Designed for applicable BMW N55 and S55 applications including:
- BMW F20 M135i
- BMW F21 M135i
- BMW F22 M235i
- BMW F23 M235i Convertible
- BMW F30 335i
- BMW F31 335i Touring
- BMW F32 435i
- BMW F33 435i Convertible
- BMW F87 M2
- BMW F87 M2 Competition
- BMW F80 M3
- BMW F82 M4
- BMW F83 M4 Convertible
MMX currently lists F2X, F3X, F80, F82 and F87 applications from 2011–2021 with N55 and S55 engines.
Please confirm exact vehicle and engine specification before ordering.
Important – Crank Hub Not Included
This product is the MMX Crank Hub Capture Plate only.
It does not include:
- MMX Single-Piece Crank Hub
- MMX 4-Pinned Crank Hub
- Replacement crank hub assembly
The Capture Plate can be installed with the existing OEM crank hub or purchased alongside a compatible MMX crank hub separately.
What's Included?
The MMX Crank Hub Capture Plate Kit includes:
- MMX T-6061 billet aluminium Capture Plate
- Required mounting hardware
MMX part number:
MMR20-1002
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