When Should Car Tires Be Replaced?by Jody L. Campbell
If your tires don't have enough tread or have uneven wear or other defects, your safety on the road is compromised. The minimum legal limit for tread depth in the United States is 2/32 of an inch. However, at this minimum the effectiveness of your tires might be greatly reduced during inclement weather. Several factors should be evaluated to know when to replace your tires.
Most new car tires come with 8/32 to 10/32 of an inch in tread depth. Because the tread's job is to provide traction on adverse roads, it's important to have enough tread to handle the job during inclement weather. Tread is needed to clear a path for the footprint of the tire to firmly contact the road. When it can't, your ability to maneuver the car will be greatly diminished. While wear-bar indicators are placed on tires to warn drivers when their tires reach 2/32 of an inch, the tire is at risk in bad weather with less than 4/32 of an inch left.
The Wear Pattern
Inspecting the wear pattern of your tires is just as important as checking how much tread you have left. Don't just look at one section of your tread to determine whether you need new tires. Inspect the entire circumference of the tread to try to determine if there is uneven wear. What you can see on the outside edge of the tread may not be the same measurement on the inside edge. Many variables can cause premature tire wear. The car may need alignment or have bad suspension or front end components. Not performing scheduled rotations and balances are also common reasons for premature tire wear. Uneven wear can mean part of the tread is compromised while another part of the same tire looks OK. For safety, go with the lowest reading of tread depth on a tire and have a qualified technician check out your car to see why the tires have worn unevenly.
The sidewall of the car tire is durable but surprisingly soft. This provides comfort, as a stiff sidewall tire offers a more rigid ride not comfortable in most family sedans. When there is a cut, gouge or crack in the sidewall of the tire, no matter how much tread depth is left, it should be replaced immediately.
One of the leading contributors to uneven tire wear is failing to rotate the tires. The front tires while steering will wear more tread along the edges. If they stay on the front for an extended period of time, they're going to wear faster than the rear tires, which is why rotations should be performed every 6,000 to 9,000 miles. Have the balance of the tire checked every time it's off the car for a rotation.