Description
Issues relating to the standard three-piece crank hub on the S55 & N55 engine are (unfortunately) widely known, but these are fully addressed with the installation of the MMR Performance one-piece billet Crank Hub, together with the option to add our Capture Plate for ultimate security.
The OE crank hub unit’s friction plate are known to slip, causing the timing to alter enough that piston-to-valve contact can occur and, if not totally standard and within the warranty period, leaves owners with a very expensive repair bill!
We have developed this Single-Piece Crank Hub together with our optional Capture Plate to ensure owners have complete peace of mind, whether on an untuned factory car or equally for those that wish to increase the power and torque output without ever having to worry again; MMR have engineered the most comprehensive solution on the market and at one of the most compelling price points.
The crank hub is machined from billet EN36 steel that’s been heat-treated with a 0.75mm case hardening, making it incredibly strong and durable. The one-piece design ensures the friction plates can no longer slip and with a new crank bolt tightened appropriately, this alone delivers the transformational improvement in reliability versus the OE version.
As MMR Performance offers two versions of the Single-Piece Crank Hub, which is best for you, pinned or unpinned? For most standard to Stage 1 tuned S55 & N55 engines, this unpinned MMR Single-Piece Crank Hub is more than sufficient. Installation is more straightforward as the end of the crankshaft does not need to be precision drilled to mount the four locating dowels. However, for high power/torque engines tuned beyond this level, we recommend the upgraded pinned version of the Crank Hub that incorporates the 4-pin dowel drive mounting for the ultimate engine security. The 4-pin version is part number MMR20-1004.
Finally. alongside the Crank Hub, the optional MMR Capture Plate ensures that owners have complete peace of mind.
This Capture Plate removes the possibility for the crank bolt to be able to loosen with the engine’s vibrations or harmonics. The Capture Plate is an additional billet aluminium hat that securely bolts over the entire head of the crank bolt, making it literally impossible for the bolt to come undone. Please select from the product option below at point of ordering to include a Capture Plate with your order.
S55 and N55 bolt torque – 100Nm initial torque plus 270 degrees.
This will fit all models with N55 and S55 engines.
Most popular models:
BMW M2 F87 2015-2018
BMW M2 Competition F87 2018-2021
BMW M3 F80 – 2014-2019
BMW M4 F82 – 2014-2020
BMW M135i F2x 2011 – 2019
BMW M235i F2x 2013 – 2020
BMW 335i F3x 2011-2019
BMW 435i F3x 2013-2020
