MMR One-Piece Crank Hub with 4 Pins and Fixing Plate for BMW N55 S55 2011-2021

MMR 4 Pin Monobloc Crank Hub for BMW N55 & S55

Engine failures caused by the standard three-piece crank hub in S55 and N55 engines are (unfortunately) well-known, but are fully resolved by installing the MMR Performance 4-Pin Monobloc Crank Hub. Furthermore, our Crank Hub Capture Plate can be added for ultimate protection.

Monobloc Crank Hub with a 4-pin location that locks to the end of the crankshaft.

The central part of the MMR kit is the CNC-machined monobloc crank hub, manufactured in the UK, created from solid EN36 steel with 0.75mm heat treatment and surface hardening, making it incredibly strong and durable. It includes four aerospace-precision machined pins that mechanically lock the hub to the end of the crankshaft, plus a new OE bolt.

Installing these pins is not a job for amateurs. To make the work easier for professionals and ensure that crankshaft modifications are performed safely and accurately, the MMR kit includes a complete installation template with a bolt-on drill guide, a positioning bolt for this guide, and a high-speed rolled HSS drill bit.

The one-piece design, together with the four-pin positioning, ensures that the friction plates cannot slip. With the new original crankshaft bolt correctly tightened, a substantial improvement in reliability and peace of mind is achieved compared to the original version.

Features

One-piece design.
X4 aerospace-precision machined pins.
Manufactured from heat-treated EN36 steel.
Available with retention plate.
Complete kit with everything needed, including drill template and drill bit.
The ultimate solution to prevent crankshaft hub failures.

Additional Information

In addition to our crank hubs, the optional MMR Capture Plate ensures complete peace of mind for owners. Our capture plate eliminates the possibility of the crankshaft bolt loosening due to engine vibrations or resonances. The capture plate is an additional piece of machined aluminum that bolts securely over the head of the crankshaft bolt, making it virtually impossible for it to come loose. The part number for the capture plate is MMR20-1002.

Installation Information

BMW S55 & N55 bolt torque: 100 Nm initial torque plus 270 degrees.
Vehicle Compatibility

Series

1 Series

2 Series

3 Series

4 Series

Chassis Code

F2x

F3x
F80
F82
F87

Model Year

2011 - 2021

Model Variant

M135i
M235i
335i
435i
OG M2
M2C
M3
M4

Engine Code

N55
S55