Precision Designed S55 M3/M4/M2C and N55 1 Piece Keyway Crank Hub

The Precision Designed Motorsport 1-piece crank hub design eliminates the possibility of a crank hub from spinning. This state of the art crank hub is designed to have a keyway, with a significantly higher shear strength over traditionally seen dowel pin designs. Comes with a carbide drill bit and drilling fixture guide.

The S55, whether stock or modified, is prone to the possibility of crank hub failure. The OEM crank hub is a 3 piece design, utilizing friction discs to retain engine timing. The friction disc depends on clamping force to clamp down the pieces of crank hub together. As the engine rotates counter clockwise, over time the crank bolt can slowly back out and loses its clamping force. This will cause engine timing to spin out of position. With enough load, engine timing can significantly be out of timing, causing the intake valves to hit against the engine piston. Severe Crank Hub failure such as this will require replacements of intake valves, and in more serious cases a full valvetrain rebuild, which are both very expensive repairs. We recommend to perform a crank hub service as preventative maintenance. While not all crank hubs fail, preventing it from failing will save you thousands of dollars and give you peace of mind!