Inspecting Tires

A tire inspection will consider Tread Depth, Tire Pressures, Wear Patterns, and Tire Sizing compared to the recommended sizing.

Tread Depth

Tread depth should be measured in the section of the tire that is worn the most.

6/32” or greater tread – Tire will still perform as originally designed. Traction, stopping distance, and all-season performance are satisfactory.

4/32” to 5/32” of tread – All season performance will suffer. The risk of hydroplaning will increase and stopping distance on any surface increases.

3/32” or less tread – The risk of hydroplaning is severe, and the stopping distance almost doubles that of new tires. Tires are in immediate need of replacement when at these tread depths.

In some locales, 2/32” of tread is the depth reading at which a tire is considered legally in need of replacement.

Tire Pressure

Tires should be inflated to the vehicle manufacturer’s recommended tire pressure. Usually, this is stated on a door jamb placard or in the vehicle’s owner’s manual.

Here is an example of the tire information placard in a door jamb.

Depending on the severity, tires that are underinflated can cause premature wear, a decrease in load carrying capacity of the tire, a decrease in the quality of the vehicle’s handling, a decrease in ride quality, and an increase in rolling resistance which increases the heat of the tire. This can result in immediate failure of the tire.

Tires that are overinflated can cause premature tire wear (especially in the center of the tread), harder ride than normal, a decrease in traction quality, and an increase in risk of tire failure.

Wear Patterns

Tires that exhibit specific wear patterns are indicators of specific types of failure either in tire maintenance or possible mechanical failures with the vehicle.

Shoulder or Edgewear

More wear on the edge of the tire than on the rest of the tread usually indicates problems with the alignment and possible lack of proper tire rotation.

Cupping and Feathering

If there is cupping or feathering in the tread, this could be an indication of worn suspension parts such as shocks or struts, over-inflation, alignment issues, or a lack of proper balance of the tires.

Fronts Wearing More than the Rears

If the front tires are more worn than the rear, this is usually an indication that the tires have not been rotated regularly.

Tire Sizing

If the tires that are currently installed on the vehicle are not the same as what the manufacturer recommends, it will change the dimensions of the tire compared to what the vehicle is designed to accommodate. Some vehicle malfunctions that the wrong tire size can cause:

• Tire rubbing or hitting components on the vehicle
• Speedometer displaying inaccurately
• Antilock brake and traction control malfunctions
• Vehicle not handling or riding as designed

Recommended tire sizing can also be found on the door jamb placard or in the vehicle’s owner’s manual.