Change your BMW selection
Expert's advice:
In the BMW S55 engine, the camshafts are driven by a timing chain connected to the crankshaft. This chain runs over a sprocket mounted on the crank hub. In the factory setup, the sprocket is not mechanically fixed to the crank hub, which can pose a risk—especially in tuned engines. Under increased power and load, the sprocket may slip, causing the engine timing to go out of alignment.
The Mosselman S55 Crank Hub addresses this issue with a pinned design, significantly improving engine reliability and safety. We strongly recommend this upgrade for heavily tuned engines that place greater stress on the crank hub and sprocket. This upgrade is available for the BMW M2 Competition, M3, and M4 equipped with the S55 engine.
