If there is unexpected snapping, extension or other damage to a timing belt or tension roller, there could be uncontrolled movement by pistons and valves and they could clash. The consequence could be irreparable damage to engine parts whose repair would then be very expensive.

The distribution mechanism includes tension rollers, whose task is to correctly tighten the timing belt. The correct setting and quality of timing belts and tension rollers are therefore exceedingly important for the long service life of an engine and the safe operation of a vehicle.