Tire wear patterns, such as scuffing, cupping and outside shoulder wear, often are an indication of a larger problem with a vehicle’s chassis components., reports Al Lynch, manager of technical services for Moog Automotive.

"The cause of uneven tire wear can be as simple as incorrect air pressure," says Lynch, "but it also can be the result of loose parts such as struts mounts, ball joints or steering linkage. Weak or fatigued components like shock absorbers or coil springs also can cause undesirable tire wear. Once a particular tire wear pattern develops, it usually will remain there for the life of the tire. New tires also will begin to wear prematurely or unevenly if the cause of the problem is not corrected."

A common tire tread wear pattern is excessive wear on both the inside and outside edges of the tire. This often is the result of air pressure below the manufacturer’s recommendation, but also can be the result of high-speed cornering.

Other tire wear patterns, like cupping, usually can be traced to loose or worn steering or suspension components. Cupped spots in the tread are caused by sudden, erratic movement of the tire. This can be caused by loose wheel bearings, ball joints, tie rods, weak shocks, suspension bottoming from weak springs, or a tire out of balance.

A diagonal tread wear pattern on rear tires usually is an indication of incorrect wheel alignment on the rear tires. If the toe setting is incorrect, the tire will try to travel in a direction different from the vehicle. This only happens for a moment and then the tire is forced back, resulting in a diagonal scuff wear pattern.

The rear suspension should be inspected before setting toe to ensure that the incorrect toe was not the result of loose or worn parts. When this condition occurs it also can affect the front wheel steering. Rear tire wear patterns on front-wheel-drive vehicles will vary depending on the tire type (all season or highway tread) and tire manufacturer.

In order to achieve optimum tire performance, vehicle owners should follow a preventive maintenance schedule that includes frequent checks of air pressure and tire rotation every 6,000 to 7,500 miles or when recommended by the vehicle manufacturer.

"Every car owner should have a tire gauge to monitor tire pressure once a month or whenever they check their oil," says Lynch. "Tire pressure should conform with the manufacturer’s recommendations – usually found inside the passenger door, door jamb or glove box – to accommodate the rated vehicle load."

Tire wear patterns often are easier to feel than to see, adds Lynch. "Before feeling the tire," he cautions, "make sure there are no sharp objects embedded in the rubber which could result in a cut or abrasion. Also make sure the engine is off, the transmission is in park and the parking brake is engaged.

"As you check each tire, be sure to feel both side to side and up and down the tread. If you think you can feel a wear pattern or cupping in the tread, or you can see a tire wear pattern, you should take your vehicle to a qualified technician for a thorough inspection and wheel alignment check.

"It is very important that the vehicle be inspected thoroughly and needed repairs be completed prior to wheel alignment. Irregular tire wear patterns are the visible symptoms. Unless the cause is determined and corrected, it’s possible the symptom will return. This can be both aggravating and expensive."