MMX Performance BMW S55 / N55 One-Piece High HP Crank Hub Upgrade Kit - 4-Pin

*Recommended for high-powered cars over 700HP*

Engine failures caused by the standard three-piece crank hub on the S55 and N55 engine are (unfortunately) well known, but these are fully addressed with the installation of the MMR Performance 4-pinned single-piece crank hub. Together with the option of adding our Capture Plate for ultimate security.

The centrepiece of the MMR kit is the UK made CNC-machined one-piece crank hub, created from billet EN36 steel that's heat-treated with a 0.75mm case hardening, making it incredibly strong and durable. Included are four aerospace precision machined dowels that mechanically lock the hub to end of the crank itself, plus a brand new OE bolt.

Installation of these dowels is certainly not a DIY job. But, to make the job easier for the professionals, ensuring that the required crank modifications are made safely and accurately, the MMR kit also includes a full installation jig that includes a bolt-on drilling guide, a location bolt for this guide, plus an HSS rolled high-speed drill bit.

Together, the single-piece design combined with the four-pin location ensures that there is simply no way that the friction plates can ever slip. With the new OE crank bolt tightened appropriately, this delivers a transformational improvement in reliability and peace of mind versus the OE version.

READ ABOUT CRANK HUB FAILURES HERE