Unusual tire wear may be caused by over- or under-inflation of the tire, or by improper alignment of the tire. Other causes include damaged or worn shocks or struts or the tire not having been properly rotated.
When a tire is over-inflated, it leads to increased wear in the middle of the tire tread. Conversely, an under-inflated tire leads to more wear on both edges of the tire. Ensuring that the tires are inflated at the proper level is an important step towards preventing unusual wear and tear of tires.
If the wheel alignment of a tire is out of specification, this leads to increased wear and tear on one edge of the tire, but not the other. This can also lead to uneven wear on the edge of the tire, which is known by tire specialists as "feathering." Feathering can also result from the tires not being properly rotated.
If any shocks, struts or other suspension components of a car are worn or have sustained damage, this leads to an indentation on the tire's surface known by professionals as "cupping." In general, keeping up with the maintenance of a set of tires helps prevent incidents of unusual tire wear.