The most important clues which a professional uses to diagnose tire wear problems are the ways in which the tire tread is worn.
Tread wear patterns are classic indicators of over or under inflation and alignment problems.
Low Pressure
If you have been driving with under inflation (low pressure) the tires will be more worn on both the shoulders because an under inflated tire tends to lift up in the center of the tread when it is in use.
Excess Pressure
If the vehicle has been used with too much pressure (over inflation) the center of the tire will be more worn than the outside edges because an over inflated tire tends to be rounder and the outside is lifted off the ground. Correct pressure will cause the tire to wear evenly across the entire tire.
Misalignment
Sometimes you may notice wear just on one edge or the other. Usually this is caused by a problem with the wheel alignment, not tire pressure.
Camber Wear (or one side wear)
When an inner or outer rib wears faster than the rest of the tire, the need for wheel alignment is indicated. There is excessive camber in the front suspension, causing the wheel to lean too much to the inside or outside and putting too much load on one side of the tire. The car may simply need the wheels aligned, but misalignment could be due to sagging springs, worn ball joints, or worn control arm bushings. Because load has a great affect on alignment, be sure the car is loaded the way it's normally driven when you have the wheels aligned; this is particularly important with independent rear suspension cars.
Feathering
Feathering is a condition when the edge of each tread rib develops a slightly rounded edge on one side and a sharp edge on the other. By running your hand over the tire, you can usually feel the sharper edges before you'll be able to see them. The most common cause of feathering is incorrect toe-in setting, which can be cured by having It set correctly. Occasionally toe-in will be set correctly and this wear pattern still occurs. This is usually due to deteriorated bushings in the front suspension, causing the wheel alignment to shift as the car moves down the road.
The solution is to have the wheels aligned as soon as possible so as to stop this abnormal wear. Other tire wear problems are much less frequent and more difficult to diagnose but if your are checking your tire pressure regularly and inspect your tires together with performing a rotation every 5,000 miles you will be taking important steps to enjoy a maximum life from your tires.
If you notice any unusual wear on your tires, swing into any Town Fair Tire for a free tire inspection.