MMX BMW S55 & N55 Single Piece Crank Hub Upgrade

The MMX Single Piece Crank Hub Upgrade is the ultimate solution to the well-documented crank hub failures affecting BMW’s S55 and N55 engines. Designed with a 4-pin dowelled single-piece design, this upgrade eliminates the risk of the factory three-piece hub slipping – a known cause of catastrophic engine failure in M2, M3, M4, and N55-powered models.

CNC-machined in the UK from heat-treated billet EN36 steel with 0.75mm case hardening, the hub offers exceptional strength and durability. Four aerospace-grade precision dowels mechanically lock the hub to the crankshaft, preventing any possibility of movement. The kit also includes a brand new OE crank bolt for complete security.

To simplify installation, the MMX kit comes complete with a bolt-on drilling guide jig, location bolt, and HSS rolled drill bit – ensuring professional fitment is accurate, safe, and straightforward. For those seeking the ultimate level of security, the hub is also available with an optional capture plate.

Key Features:

• Part Number: MMR20-1004

• Single-piece design – eliminates OE crank hub slip issues

• 4 aerospace-grade precision dowels for a secure mechanical lock

• Machined from heat-treated billet EN36 steel with case hardening

• Supplied with a new OE crank bolt

• Includes full installation jig, drilling guide, and HSS drill bit

• Optional capture plate for additional protection

• Designed and manufactured in the UK

• The ultimate reliability upgrade for BMW S55 and N55 engines

Compatibility:

• BMW 1 Series (F20/F21) – M135i (N55)

• BMW 2 Series (F22/F23, F87) – M235i, OG M2 (N55), M2 Competition (S55)

• BMW 3 Series (F30/F31, F80) – 335i (N55), M3 (S55)

• BMW 4 Series (F32/F33, F82) – 435i (N55), M4 (S55)

• Model Years: 2011–2021

Protect your BMW from crank hub failure with the MMX S55 & N55 Single Piece Crank Hub Upgrade – precision-engineered for strength, durability, and complete peace of mind.