BMW S55 Crank Hub Failure – What It Is and How to Fix It

BMW S55 Crank Hub Failure – What It Is and How to Fix It

If you own a BMW M3, M4, or M2 Competition with the S55 engine, you’ve probably heard about crank hub failure. It’s one of the most talked-about issues in the S55 community, and for good reason — when it happens, it can lead to catastrophic engine damage and a repair bill no enthusiast wants to face.

In this article, we’ll explain what crank hub failure is, why it happens, and the permanent fix that keeps your S55 safe — the BMW S55 Crank Hub Upgrade.

What Is Crank Hub Failure?

The crank hub is a critical component that connects the crankshaft to the timing chain system in your engine. On the BMW S55, the factory crank hub design is a multi-piece, friction-fit system. Under high load — such as hard acceleration, aggressive downshifts, or tuning for more power — the crank hub can slip.

When it slips, the timing between the crankshaft and the camshafts is thrown off, leading to:

  • Check engine lights and fault codes
  • Rough running or misfires
  • Complete engine failure if valves and pistons collide

This problem can occur even on stock, unmodified cars, though it’s more common in tuned or track-driven vehicles.

Why the S55 Crank Hub Slips

BMW’s original design relies on surface friction alone to hold everything in place. While it works under normal driving conditions, it’s a weak point in high-performance scenarios.

  • Aggressive launches put sudden torque spikes through the crank hub.
  • Tuned engines increase power output beyond what the OEM design tolerates.
  • Track driving keeps the engine in high RPM ranges where the chance of slip is higher.

Unfortunately, once the hub slips, there’s no going back without tearing down the front of the engine — and sometimes rebuilding the entire motor.

The Permanent Fix – BMW S55 Crank Hub Upgrade

The most reliable way to prevent crank hub failure is to replace the OEM multi-piece unit with a one-piece, keyed or pinned crank hub upgrade.

At 5150 AutoSport, we offer a BMW S55 Crank Hub Upgrade designed to eliminate the possibility of timing slip. Our upgrade uses a more secure mechanical connection between the crankshaft and timing system, providing:

  • Permanent reliability under any driving conditions
  • Peace of mind for tuned and track cars
  • Fitment for BMW M3 (F80), M4 (F82/F83), and M2 Competition (F87)

This isn’t just a fix for failures — it’s a preventive upgrade that every S55 owner should consider, especially before increasing horsepower or taking the car to the track.

When to Upgrade Your Crank Hub

We recommend replacing the crank hub:

  • Before tuning your car for more power
  • If you track your S55-powered BMW
  • If you’ve noticed timing-related fault codes or unusual engine behavior

Even if your S55 is stock, upgrading the crank hub is cheap insurance compared to the cost of a full engine rebuild.

Final Thoughts

The BMW S55 is an incredible engine with huge performance potential, but the crank hub is a well-known weak link. By upgrading to a one-piece pinned crank hub, you can protect your investment and drive with confidence.

If you’re ready to protect your M3, M4, or M2 Competition, check out our BMW S55 Crank Hub Upgrade from 5150 AutoSport — in stock and ready to ship.

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