Main Serpentine Drive Belt - M235i/M240i Racing

The main drive belt runs the alternator and power steering pump on the F22 M235i/M240i Racing's N55 engine (the water pump is electric). This belt for the Racing model is shorter than standard to account for the missing A/C compressor (optional on M235iR/M240iR). Note: if your car has the optional A/C system you use a standard N55 belt.

A belt is easy to inspect during routine track prep. If there are cracks running across the ribs, sections missing, the edges are frayed, or the threads are visible on the belt surface, the belt should be replaced immediately. Also pay attention to a belt that is running off the edge of a pulley as that is a sure sign of an impending failure.

If you can, inspect and test the pulleys before ordering your belt - tensioner, deflection, and power steering. Or plan to order new pulleys and tensioner with your belt. These pulleys are made of plastic and shatter with age, causing potentially expansive/expensive damage to your engine, radiator, etc. They usually last longer than the belt but now is the best time to replace them. Since they are bolted on, not pressed, they are easy to replace. Also test the belt tensioner at the same time as the pulleys. A failing tensioner can let the belt slip off the pulleys.