Getting Alignment & Tension Right

Correct tension and near perfect alignment of the pulleys (sheaves) are the two essentials for long belt life. Poor alignment and/or tension can destroy a belt within a few hours and cause equipment failure.

Aligning and correctly tensioning a belt are not difficult but these jobs do require patience, especially if alignment or tension have been poor. They may have been poor because a bracket is bent or a pulley has worn beyond its service life.

Poor pulley alignment – belt wears and fails

Too little tension – belt slips, equipment (such as alternator or pump) fails to operate properly. Belt "squeal" is often a tell-tale sign of a loose belt, though, more rarely, it can also be caused by a belt running around a seized pulley.

Too much tension (overtight) – strains bearings, likely leading to premature failure of the bearing and pulley.

Belt dust – evidence that alignment or tension need adjusting.

Time taken to get both alignment and tension "perfect" will be rewarded with much longer service life and trouble-free running.