Why belt misalignment is bad

Did you know that misalignment can destroy a belt in a matter of days? In most cases it is assumed the belt is of insufficient quality while pulley misalignment is in fact the major cause of premature accessory belt failure.

Just a few degrees of misalignment can increase a Micro-V^® or fan belts’ operating temperature by 15°C, reducing belt life by as much as 75%. Misalignment can also create belt routing problems, excessive wear, noise and belt stability problems which can all cause your customer to come back to the workshop thinking the belt you installed failed.

If you want to avoid early comebacks, misalignment must be found and corrected before installing a new Micro-V belt.

Watch the video and see what happens when pulleys and belts are misaligned.

Two types of misalignment

There are two types of misalignment: parallel or angular. Both types of misalignment can be easily detected with a laser alignment tool.

Parallel misalignment refers to pulleys that are outside the plane of other pulleys in the drive system but whose shafts remain parallel. Proper positioning of a pulley on a shaft will help ensure all pulleys are in a common plane.

Angular misalignment refers to pulleys which are within the same drive system plane but are tilted because their shafts are not parallel. A combination of both is also possible.

Belt misalignment and noise

A chirping noise that increases in frequency as the engine is revved up can be the result of belt vibration caused by misaligned pulleys. In fact most cases of belt noise are caused by misaligned pulleys and belts.

As a misaligned auxiliary belt span enters the grooves of a pulley, initial contact is made with only one side of the groove. The greater the misalignment angle, the greater the radial sliding length experienced by the belt ribs as the belt seats in the pulley which causes frictional vibrations or chirping. You can read more information about diagnosing a noise drive here.

Want to know more about noise in the accessory belt drive system and how to overcome it? Download our accessory belt drive system troubleshooting guide here below.