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Description

MMX Billet 4-Pin Single-Piece Crank-Hub Upgrade Kit for BMW Vehicles (with N55 and S55 engines)

Crank hub-related engine failures on BMW’s S55 and N55 engines are unfortunately well documented. MMX Performance addresses these issues with its Billet 4-Pin Single-Piece Crank Hub Upgrade Kit — engineered to eliminate the risk of crank hub slippage in high-power and high-torque applications. This upgraded version of MMX’s proven Single-Piece Crank Hub incorporates four precision-machined dowels that mechanically lock the hub to the crankshaft, eliminating the possibility of rotational slip between friction plates that could lead to catastrophic piston-to-valve contact. The core of the system is a CNC-machined, UK-manufactured hub made from billet EN36 steel and case-hardened to 0.75mm for extreme strength and durability. To support professional installation, MMX includes a complete jig set featuring a bolt-on drilling guide, location bolt, and high-speed drill bit to ensure precise dowel installation. While MMX also offers an unpinned version suitable for stock or Stage 1 builds, this 4-Pin Crank Hub is strongly recommended for engines producing elevated power levels. Additionally, the optional MMX Capture Plate adds a further layer of security by preventing crank bolt loosening due to engine harmonics — a known weak point of the OE design. The Capture Plate fastens over the crank bolt head, making unintentional loosening virtually impossible. Compatible with S55-powered BMW M2 Competition, M3, and M4, as well as N55-equipped M2, M135i, M235i, 335i, and 435i models, the MMX Performance 4-Pin Crank Hub Upgrade delivers unmatched reliability at a compelling price point — making it an essential upgrade for serious builds.

Features

One‑piece crank hub construction
CNC‑machined from billet EN36 steel with 0.75 mm case‑hardening
Four precision aerospace‑machined dowel pins mechanically lock the hub to the crankshaft, preventing any rotational slip
Designed to address known failures in N55 and S55 engines under high power / torque builds
Supplied as a complete kit including new OE crank bolt and installation jig (drilling guide, location bolt, high‑speed drill bit)
Optional billet aluminum Capture Plate available to secure crank bolt against loosening

Applications

BMW 135i: E82, E88 (2010-2013)
[N55 – 3.0L I6 turbo]
BMW 335i: E90, E91, E92, E93, F30, F31, F34 (2010-2015)
[N55 – 3.0L I6 turbo]
BMW 435i: F32, F33, F36 (2013-2016)
[N55 – 3.0L I6 turbo]
BMW 535i: F07, F10, F11 (2011-2017)
[N55 – 3.0L I6 turbo]
BMW 640i: F06, F12, F13 (2011-2018)
[N55 – 3.0L I6 turbo]
BMW 740i: F01, F02 (2012-2015)
[N55 – 3.0L I6 turbo]
BMW M135i: F20, F21 (2012-2016)
[N55 – 3.0L I6 turbo]
BMW M2: F87 (2016-2018)
[N55 – 3.0L I6 turbo]
BMW M2 Competition: F87 (2018-2021)
[S55 – 3.0L I6 twin-turbo]
BMW M2 CS: F87 (2020)
[S55 – 3.0L I6 twin-turbo]
BMW M235i: F22, F23 (2014-2016)
[N55 – 3.0L I6 turbo]
BMW M3: F80 (2014-2018)
[S55 – 3.0L I6 twin-turbo]
BMW M4: F82, F83 (2014-2020)
[S55 – 3.0L I6 twin-turbo]
BMW M4 CS: F82 (2017)
[S55 – 3.0L I6 twin-turbo]
BMW M4 GTS: F82 (2016)
[S55 – 3.0L I6 twin-turbo]
BMW X1 xDrive35i: E84 (2013-2015)
[N55 – 3.0L I6 turbo]
BMW X3 xDrive35i: F25 (2011-2017)
[N55 – 3.0L I6 turbo]
BMW X4 M40i: F26 (2015-2018)
[N55 – 3.0L I6 turbo]
BMW X4 xDrive35i: F26 (2014-2018)
[N55 – 3.0L I6 turbo]
BMW X5 sDrive35i: F15 (2014-2018)
[N55 – 3.0L I6 turbo]
BMW X5 xDrive35i: E70, F15 (2011-2018)
[N55 – 3.0L I6 turbo]
BMW X6 xDrive35i: E71, F16 (2010-2019)
[N55 – 3.0L I6 turbo]

Notes

READ ABOUT CRANK HUB FAILURES HERE
Recommended for high-powered cars over 700hp
Only compatible with N55 and S55 engines

About MMX Performance

MMX Performance is a UK‑based specialist in performance parts for BMW and MINI vehicles, crafting high‑quality upgrades that blend precision engineering, rigorous testing, and motorsport heritage. Driven by enthusiast culture, MMX designs its products in the UK — often putting them through track validation — to ensure durability, fitment accuracy, and on-road performance. Their catalog spans drivetrain components, spacers, hardware, and chassis enhancements, all tailored to elevate both the driving experience and visual appeal of BMW and MINI models.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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MMX Billet 4-Pin Single-Piece Crank-Hub Upgrade Kit for BMW Vehicles (with N55 and S55 engines) [MMR20-1004/MMR20-1004FK]

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MMX Billet 4-Pin Single-Piece Crank-Hub Upgrade Kit for BMW Vehicles (with N55 and S55 engines)

Features

Applications

Notes

About MMX Performance

Reviews