Mosselman S55 Crank Hub Upgrade, BMW F8x M2C/M3/M4

Expert's advice:

In the BMW S55 engine, camshafts are connected to the crankshaft via a camshaft chain. This chain, in turn, is connected to a sprocket that’s mounted on the crank hub. In stock form, this sprocket is not fixed on the crank hub, putting tuned engines at considerable risk of failure. If the sprocket shifts out of alignment due to increased power, so does the engine’s timing.

The Mosselman S55 Crank Hub offers a vast improvement in terms of engine safety. We recommend the crank hub modification for heavily tuned engines that put increased levels of strain on the crank hub and sprocket.

Important Note: The Crank Hub upgrade should only be installed by a qualified shop or technician (timing tools are required). Improper installation can cause damage to the engine.

Mark Hendrikx - Automotive engineer at Mosselman