BMW S55 Crank Hub Upgrade: Enhancing Performance and Reliability

The BMW S55 engine, commonly found in the M2, M3, and M4 models, is known for its powerful performance. However, one of the prevalent concerns among owners and enthusiasts is the potential failure of the stock crank hub. This component is responsible for transferring power from the crankshaft to the valve timing chain sprocket and the oil pump chain sprocket, ensuring accurate timing and smooth engine operation. Upgrading the S55 crank hub can alleviate these concerns and provide increased reliability, especially for those seeking to tune or modify their vehicles for enhanced performance.

SSR Performance and Mosselman Turbo Systems offer two notable aftermarket solutions – the SSR Performance Double-Keyed 4-Pin S55 Crank Hub and the Mosselman S55 Crank Hub Upgrade. Both crank hub upgrades are designed to improve engine safety and stability, particularly in heavily tuned engines that experience increased strain on the crank hub and sprocket. These upgrades involve a double-keyed locking assembly and the use of pins to prevent rotation in relation to the crankshaft, ensuring proper synchronization of the valve timing chain and oil pump chain sprockets.

It is essential to have a qualified technician or shop perform the crank hub upgrade, as the process requires specialized timing tools. By investing in an S55 crank hub upgrade, BMW owners can expect increased durability and reliability, ultimately resulting in peace of mind and better performance from their high-performance vehicles.

BMW S55 Crank Hub Upgrade Overview

The BMW S55 engine, commonly found in models such as the M3, M4, and M2C, is a high-performance engine with powerful capabilities. However, one issue that has been frequently reported by owners and enthusiasts is the potential for crank hub slippage. To address this issue, a crank hub upgrade is often recommended for individuals engaging in spirited driving, enhancing engine reliability and performance.

The S55 Crank Hub Upgrade focuses on replacing the stock crank hub with a keyed unit. This double-keyed and two-piece design has been well-documented to provide significant benefits over the stock S55 hub. In order to install the upgrade, four holes are drilled into the S55 crankshaft, allowing for the new keyed crank hub to lock into place permanently, and thus preventing any relative rotation to the crankshaft.

SSR Performance offers a popular 4-pin crank hub upgrade that replaces the stock component with a unit featuring four “keys” or “pins”. This is a highly recommended solution due to its proven effectiveness in solving the crank hub slippage issue, resulting in increased reliability and peace of mind for drivers.

Some of the key components in the upgrade kit provided by SSR Performance include the double-keyed 4-pin crank hub, an upgraded crankshaft bolt, a crankshaft locking pin, and new OEM chain tensioners. All these components work together to ensure a more secure and stable connection between the crank hub and the crankshaft.

In summary, the BMW S55 Crank Hub Upgrade is a worthwhile investment for those interested in maintaining and improving the performance and longevity of their M3, M4, or M2C vehicles. By upgrading to a keyed crank hub, drivers can experience enhanced engine reliability and reduce the risk of costly damages due to crank hub slippage.

The Importance of Crank Hub Upgrades

Upgrading the crank hub of a BMW S55 engine can significantly reduce the risk of engine damage and engine failure. The S55 engine is commonly found in high-performance BMW models like the F80 M3 and F82 M4. Although these vehicles are known for their performance and reliability, a weakness has been identified in the crank hub design which can lead to catastrophic engine failure. By upgrading the crank hub, car owners protect their investment and ensure that their engine operates at peak performance.

Crank hub slippage is a known issue that poses a serious threat to BMW S55 engines. This problem is caused by the lack of proper keying or pinning for the crank hub, which leaves it vulnerable to timing and alignment issues. When the stock crank hub slips or loses its proper timing, the valves and pistons may collide, causing extensive engine damage. Spirited drivers, in particular, should consider these upgrades as a means of preventing this dangerous outcome.

A variety of aftermarket crank hub upgrades, like Mosselman’s S55 Crank Hub Upgrade, offer a better-than-stock improvement in terms of reliability and engine safety. These high-performance upgrades are especially recommended for those who plan to go beyond simple bolt-on modifications and pursue more aggressive tuning.

When selecting a crank hub upgrade, it’s essential to weigh the available options and consider their unique features. For example, some upgrades require no drilling of the crankshaft, making the installation process more accessible and less invasive. Such is the case with the VTT Crank Hub Upgrade—their Spline Lock technology locks the hub to the crank, ensuring a secure and robust connection.

Ultimately, investing in a quality crank hub upgrade enhances the reliability of your BMW S55 engine while also minimizing possible engine damage and future engine failures. By choosing a reliable upgrade that fits your specific needs and preferences, you can ensure that your engine remains in top shape for extended periods of spirited driving and high-performance applications.

Crank Hubs and Related Parts

The BMW S55 engine’s crank hub has been a major concern for many enthusiasts due to its potential to cause engine damage if it fails. The stock crank hub assembly consists of the hub, crankshaft bolt, and sprocket. The stock assembly often fails due to the fact that it’s not keyed or pinned, which can lead to spinning and ultimately causing catastrophic engine damage. An upgrade to a double-keyed 4-pin crank hub has been developed as a solution to this problem.

Upgrading the crank hub involves replacing the stock crank hub with a newer designed unit that has four keys or pins. These pins are used to lock the hub in place on the crankshaft, preventing it from spinning. The new keyed design includes drilling four holes into the S55 crankshaft, allowing the upgraded crank hub to be locked into place without the risk of rotation.

The stock crankshaft bolt is another crucial component in the assembly, and upgrading it to work with the double-keyed hub is necessary. It helps secure the crank hub and ensures that the timing gear and chain remain in their proper positions. By upgrading the crankshaft bolt, the integrity of the entire system is further strengthened, minimizing any potential risks or issues.

Camshafts are responsible for opening and closing the engine valves by rotating in sync with the crankshaft. An upgraded crank hub ensures that the valve timing remains accurate, as it helps prevent the crankshaft from spinning. Accurate valve timing is vital for the performance and reliability of the S55 engine.

The timing gear and chain are other essential components within this assembly. The timing gear connects directly to the crankshaft and is driven by the timing chain. With a reliable crank hub upgrade, these components can function optimally without any potential for disruption, which can ultimately lead to widespread engine damage if not addressed.

In conclusion, upgrading the BMW S55 engine’s crank hub is an essential step for any performance enthusiast looking to protect their engine from potential catastrophic damage. By upgrading the crank hub, crankshaft bolt, and ensuring the integrity of the other related components like the camshafts, timing gear, and chain, owners can have peace of mind knowing that their investment is well protected.

Upgrade Options

The BMW S55 engine is known for its performance and reliability, but some enthusiasts have reported issues with the stock crank hub’s integrity. A potential failure may cause engine valve timing to skip, leading to engine damage. One popular solution to this problem is the SSR Performance Double-Keyed 4-Pin S55 Crank Hub.

This upgrade replaces the stock crank hub with a unit that features four pins or keys. These keys improve the connection between the crank hub and crankshaft, eliminating the chance of relative rotation and ensuring a stable, secure fit.

The 4-pin design offers increased reliability over the stock unit. It involves drilling four holes into the S55 crankshaft; once installed and tightened, the new keyed crank hub upgrade effectively locks the assembly in place. This prevents slippage under heavy pressure, particularly in tuned S55 engines where increased performance demands could strain the stock crank hub.

Another option for upgrading the crank hub is the MSL Crank Hub Upgrade, recommended for heavily-tuned S55 engines. Similar to the SSR double-keyed crank hub, the MSL version also ensures the sprocket is locked onto the crank hub, avoiding unwanted movement under high-pressure conditions.

It is essential to choose a reliable and high-quality crank hub upgrade for your BMW S55 engine in order to avoid potential engine damage. Both the SSR Performance and MSL options offer enhanced safety and engine longevity through their keyed design. By investing in one of these upgrades, you can feel confident and secure in your S55 engine’s performance and durability.

Popular Upgrade Brands and Solutions

BMW S55 engines are known for their powerful performance, but many owners have experienced issues with the stock crank hub system. Upgrading the crank hub can minimize the risks associated with this critical engine component. In this section, we will discuss two popular upgrade brands and their solutions for the S55 crank hub.

SSR Performance is a renowned provider of BMW engine upgrades, and their Double-Keyed 4-Pin S55 Crank Hub has garnered significant attention in the BMW community. Priced at $949.00, this upgrade features a unique four-pin design that ensures proper alignment and added durability. It replaces the stock crank hub unit and effectively locks the new keyed crank hub in place, preventing any potential relative rotation to the crankshaft.

Some advantages of SSR Performance’s S55 Crank Hub upgrade include:

  • Enhanced reliability
  • Four-pin design for added security
  • Trusted brand in the BMW community

Another prominent company in the BMW tuning scene is Maximum PSI. Although there isn’t a specific crank hub product attributed to them in the search results, they are highly regarded for their expertise in BMW engine upgrades and performance parts. It’s worth considering their available products and consulting with their technicians for personalized advice on crank hub upgrades and other performance enhancements.

In summary, both SSR Performance and Maximum PSI offer reliable and trusted solutions for upgrading the S55 crank hub. Investing in these upgrades can alleviate concerns related to stock crank hub issues and provide BMW owners with increased performance and peace of mind.

Installation Process

To ensure a successful BMW S55 crank hub upgrade, it’s essential to follow the proper installation process. This includes working with the right tools, adhering to BMW’s guidelines, and seeking assistance from a skilled technician when necessary. In this section, we outline the key steps involved in the crank hub upgrade to help you achieve the desired results.

Before starting the installation, gather all necessary tools and equipment, such as a 2-post automotive lift, a torque wrench capable of OEM crank bolt torque, and BMW timing tools source. Additionally, you’ll need a crank locking tool, crank seal/front seal install tools, and an engine support cradle.

Begin the upgrade process by removing the S55 valve cover to access the engine components. This step requires utmost care and precision. It’s recommended to seek the help of a knowledgeable technician to avoid causing damage to the valve cover gasket and any other delicate parts involved in the process.

Once the valve cover is removed, proceed to take off the subframe and oil pan. These steps allow you to access the necessary areas for the crank hub upgrade source. It’s crucial to perform these tasks carefully and follow BMW’s recommended guidelines to prevent any damage to your S55 engine.

With the oil pan removed, you can now access the crankshaft. At this point, the crank locking tool and other specialized BMW tools come into play. It’s essential to ensure correct alignment and installation of the keyed crank hub to the crankshaft. This is the core component of the upgrade and requires extra attention to avoid any issues related to improper installation.

Upon completing the installation, double-check all components, seals, and gasket placements. Secure the valve cover, oil pan, and subframe back into place. It may be helpful to seek professional help to ensure everything is properly aligned and functioning as expected.

The BMW S55 crank hub upgrade is a crucial enhancement to maintain the reliability of your vehicle. Following the proper installation process and working with an experienced technician can ensure the success of the upgrade and help you get the most out of your BMW S55 engine.

Avoiding Common Problems

The BMW S55 engine, found in M4, M3, and M2 Comp models, has faced some concerns about its crank hub upgrade. Although the issue may be blown out of proportion, it’s still essential to understand the problem and how to avoid it to ensure the reliability and performance of the engine.

Crank Hub Failure

A common concern with the S55 engine is the failure of the crank hub, causing relative rotation and affecting valve timing. The slippage of the crank hub is particularly worrisome due to its potential to cause significant engine damage if not addressed promptly.

The S55 engine has multiple mechanically driven components, such as water pumps and two high-pressure fuel pumps (HPFP) driven on the cam. These extra components can introduce stress on the crank hub, which, in extreme cases, may lead to a spun crank hub.

Keyed Crank Hub Upgrade

One way to mitigate these issues is to upgrade the stock crank hub to a keyed crank hub. The keyed crank hub upgrade replaces the stock unit with one that has two keys or pins. Two holes are drilled into the S55 crankshaft, allowing the new keyed crank hub to lock into place permanently without the chance of relative rotation.

The upgrade can help eliminate the risk of failure and slippage, ensuring a reliable and stable engine. It’s also a good idea to follow regular maintenance schedules and promptly address any unusual engine noises or performance issues to minimize stress on the crank hub.

By upgrading the crank hub and keeping up with routine maintenance, you can confidently enjoy the performance and power of your BMW S55 engine without worrying about common problems.

Pricing and Dealers

When it comes to upgrading the BMW S55 crank hub, there are multiple options available with varied pricing. The SSR Performance Double-Keyed 4-Pin S55 Crank Hub for BMW F8X M2, M3, and M4 is available for $949.00 at BimmerWorld. Alternatively, SSR Performance’s official website also sells the 4-Pin Crank Hub at the same price. For those looking for a billet pinned solution, RKAutowerks offers their S55 Billet Pinned Crank Hub for $1,199.00.

Mosselman has a more cost-effective Crank Hub Upgrade for BMW F8x M2C/M3/M4 at €429.00 excluding sales tax. Make sure to consider your budget and the specific features each crank hub upgrade offers before making a decision.

In terms of part availability, many of these crank hubs are either in stock or available for backorder. For example, the S55 Billet Pinned Crank Hub from RKAutowerks has 54 units in stock and can also be backordered as of now. This ensures that customers have access to these products when they need them.

If you are interested in wholesale pricing or drop shipping, it is recommended to directly contact the respective dealers or manufacturers. You can do this by visiting the SSR Performance website or reaching out to other dealers mentioned above. They generally provide contact information on their websites, and you can inquire about bulk purchases, shipping options, and policies.

Manufacturers’ timelines for shipping and handling may vary, so it is best to verify this information when placing an order. Lastly, please be aware that there might be no return policies on these crank hub upgrades. Therefore, ensure you thoroughly understand the product specifications before making a choice.

Warranty and Support

When it comes to upgrading your BMW S55 crank hub, there are a few key points to consider when it comes to warranty and support. One of the reputable companies that offer crank hub upgrades, SSR Performance, provides a warranty for their Crank Hub Fix Kit. They not only offer the product but also a professional installation service with warranty at their facility in Orange County, CA.

To schedule an appointment for the installation, you can contact SSR Performance via phone at (800) 438-2808 or through email. Their experienced team will provide you with a quote and book a slot at their 6,500 square foot facility located at 590 W Freedom Ave, Orange, CA.

Upgrading the stock S55 crank hub helps significantly in reducing the risk of a snapped crank or engine failure. The Mosselman S55 Crank Hub, for instance, is a high-end performance upgrade recommended for BMW F8x M2C, M3, and M4 models, especially for those who are looking to perform a Stage 3 tuning on their vehicle. Mosselman’s crank hub solution improves engine safety and reliability, ensuring optimal performance (source).

However, it’s crucial to note that any modification to your vehicle, especially those involving the engine’s internals, may affect your manufacturer’s warranty. For instance, BMW may not cover the costs of engine replacement if the issue is deemed to have resulted from an aftermarket component. Therefore, it is essential to weigh the potential benefits and drawbacks of upgrading your crank hub and whether or not you can afford any unexpected costs associated with potential warranty concerns.

In conclusion, a BMW S55 crank hub upgrade provides increased engine safety and performance, with reputable companies like SSR Performance and Mosselman offering solutions backed by warranty and professional support. Remember to carefully consider the potential implications on your vehicle’s manufacturer warranty before proceeding with any engine modifications.

Real Life Cases and Reviews

Crank hub upgrade has become a popular discussion point in the BMW community, especially among S55 engine owners, which power models like M4 GTS, BMW F82 M2 Competition, and M2 CS. Several real-life cases and reviews suggest that an upgraded crank hub can provide extra security and peace of mind for these owners.

Many S55 engine owners have reported the issue of the crank hub failure, leading to concerns regarding the integrity of the stock hub, bolt, and sprocket assembly 1. A failed crank hub can cause engine valve timing to skip or jump, potentially leading to irreversible engine damage.

In response to this problem, SSR Performance released a Double-Keyed 4-Pin S55 crank hub for BMW F8X M2, M3, and M4 models. This upgrade has been praised by customers for its effectiveness in addressing the crank hub issue 2. The product aims to reduce the risk of catastrophic engine damage due to a slipped crank hub, providing a more reliable driving experience for S55-powered BMWs.

A popular YouTube video demonstrates the process of upgrading the crank hub on an S55 motor. It showcases the importance of the upgrade and provides a step-by-step guide on how to lessen the risk of crank hub failure and protect the engine.

Harmonics and vibrations in the engines are among the main reasons for crank hub failure, especially in high-performance models like M4 GTS and M2 CS 3. Upgrading the crank hub helps ensure that the bolt does not loosen, maintaining the accurate engine timing necessary for proper performance.

In conclusion, upgrading the crank hub on BMW S55 motors appears to provide a higher success rate in preventing failures and avoiding irreversible engine damage. This upgrade is worth considering for owners of high-performance BMW models like M4 GTS, BMW F82 M2 Competition, and M2 CS who desire added security and peace of mind.

Additional Considerations

When considering an S55 crank hub upgrade for your BMW, it’s important to keep several factors in mind. Upgrading the crank hub can help prevent engine damage and offer more reliable performance, especially in modified cars where increased power puts additional stress on the stock components.

If you’re located in Orange County, CA, there are plenty of reputable shops that specialize in BMW performance upgrades. These experts can provide valuable insight and professional installation of the upgraded crank hub, ensuring that it is done correctly and efficiently.

Moving on to parts availability, it’s essential to verify the manufacturers’ on-hand quantities before proceeding with the upgrade. A limited supply can result in delays in shipping and longer wait times for your upgraded crank hub to arrive. However, most reputable suppliers, such as SSR Performance and Mosselman, maintain sufficient stock to cater to customer demands.

In terms of shipping, make sure to choose a reliable carrier to ensure your crank hub upgrade kit arrives safely and on time. Some suppliers may offer expedited shipping options for an additional fee if you’re working on a tight schedule or want to minimize downtime for your vehicle.

Upgraded crank hubs not only protect your engine but also support the increased power levels that come with modifying your car. The S55 engine, in particular, has unique features, such as two high-pressure fuel pumps and mechanically driven components like the water pump that can cause more stress on the crank hub. Addressing these concerns with an upgraded crank hub can lead to better overall performance and peace of mind during spirited driving.

Remember to approach your S55 crank hub upgrade with a confident, knowledgeable, and neutral mindset while ensuring a clear understanding of all aspects involved. This will ultimately contribute to a successful project and an improved driving experience.



Georg Meier

BMW technician since 1996. I began my automotive journey in 1993 as an apprentice mechanic at Automag, the world's oldest BMW dealership in Munich. With years of experience and dedication, I garnered a wealth of knowledge about the intricacies of BMW and MINI vehicles. The love/hate relationship with the brand led me to found BIMMERIST where I share expertise and insights with fellow enthusiasts.

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