As tires wear, the tread depth should be even across the entire width. Likewise the tread depth should be close to the same on all four tires. If the depth is uneven or irregular, there’s usually a specific cause. Some of the specific abnormal patterns to look for include
- excessive outer wear only
- excessive inner wear only
- excessive inner and outer wear
- too much wear in the center of the tread
- bumpy or spotty wear
Causes of Excessive Inner and Outer Tire Tread Wear
When there’s more wear on the inside or outside (not both) of the tread surface, the main cause is the vehicle’s alignment. This is a condition that’s known as a misaligned toe. In a toe-in condition, the wheel is angled so that the inside of the tire is riding on the road surface, causing excessive wear to the inside.
Just the opposite is a toe-out condition. In a toe-out condition the wheel is angled so that the outside of the tire is riding on the road surface, causing excessive wear to the outside. Naturally to correct this out of toe condition, the auto repair needs to align the vehicle.
If both the inner and outer tread surface has excessive wear compared to the center of tread surface, the most common reason is under inflated tires. When a tire is under inflated, the tire tread surface is bowed and only the outer edges of the tire come in contact with the road surface. Check the tire pressure and inflate to the factory recommended pounds per square inch (PSI).
Cause of Excessive Tire Wear in the Center of the Tread
In some cases the center of a tires tread will wear faster than the inside and outside edges. The most common reason for excess wear in the center is over inflated tires. When a tire is over inflated, the center will bulge out further than the outside edges. The result is more road contact with the center as opposed to the inner and outer edges. Check the tire pressure and deflate to the factory recommended pounds per square inch (PSI).
Causes of Bumpy or Spotty Tire Tread Wear
Bumpy and spotty tread wear can be difficult to detect with the naked eye. In most cases this type of condition will result in an uncomfortable, bumpy ride. One method to test for bumpy or spotty tread wear is to run your (gloved) hand over the tread surface.
The most common cause of this condition is bad suspension shocks or struts. The purpose of a vehicle shocks and struts is to counteract the suspension springs. When shocks aren’t functioning properly, the vehicle will bounce excessively. This bouncing affect can cause the tire to bounce on the road surface resulting in spotty or bumpy tread. The corrective action needed is to replace the defective shock or strut.
To ensure you get the longest life from a set of tires, it’s important to adhere to a routine maintenance schedule and rotate the tires every 5,000 miles. Checking your tires for irregular wear patterns and taking corrective action will help to extend the life of your tires.
James Clausen - Clausen received a Bachelors Degree in Business Administration in Automotive Management and Marketing at Northwood University, graduating ...
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