subject: Factors That Can Cause Premature Tire Wear [print this page] Your car's tires suffer wear from constant contact with the surface of the road. Even if you keep them inflated with the proper level of pressure, the treads will eventually wear to point of becoming unsafe. Adding to the problem is the fact that your vehicle's wheels will gradually move out of alignment. This too, causes premature wear on the treads.
You can extend the life of your tires by rotating them on a regular basis. This helps to distribute wear in the event your wheels are out of alignment. However, there may be other factors at work.
Below, we'll start the discussion by first exploring the different wear patterns and noting the reasons they occur. I'll then describe a quick way to test tread depth so you can make sure your tires are safe.
Identifying Different Types Of Wear
The most common type of wear occurs as the result of underinflation. You'll notice worn treads on the outer sides of your tires. This happens due to the outer edges having excess contact to the road.
The opposite effect occurs as the result of overinflation. The middle of your tire wears prematurely. This occurs because the tire rides primarily on the middle of the tread, increasing its relative contact to the road.
Occasionally, you may notice a feathering effect on your front wheels. The treads on one side will have a rounded appearance while the other side will show sharp edges. This is caused by a toe misalignment. Toe measures the variance in distances between the back of your tires to the front.
When wearing occurs on a single side, it usually indicates a problem with camber. Camber is a measurement that reflects the tilt of your wheels when viewed from the front of your vehicle. Excess camber leads to one-sided wearing.
The above wear patterns are the most common, but there are others you may notice. For example, you might see cupping, bulging (i.e. the treads separate), or a diagonal pattern. Cupping is usually due to bad shock absorbers; bulging sometimes occurs due to poor design of the treads; a diagonal pattern suggests a problem with your car's suspension.
Are Your Treads Excessively Worn?
Before we dig more deeply into the underlying causes of premature tread wear, it's worth reviewing how to determine whether you need a new set of tires. Most tire manufacturers now equip their treads with "wear indicators." Once the rubber wears to a specific point, the indicator shows, alerting you to the need for a replacement.
If your tires are not equipped with wear indicators, you can use a penny to test tread depth. Stick a penny into the tread with Lincoln's head positioned upside down. If the top of his head descends into the tread, your tire is fine (for now). On the other hand, if you can observe the top of Lincoln's head, your tire needs to be replaced.
Digging More Deeply For The Root Of The Problem
Problems associated with underinflation and overinflation are easy to resolve. Simply return your tires to the manufacturer's recommended psi. If you are able to isolate feathering or one-sided wear to toe or camber (respectively), a wheel alignment will fix the issue. As noted earlier, however, some types of premature wear are due to worn shocks and suspension problems.
You can determine whether your shocks are worn by bouncing the front of your vehicle and releasing it. If the front end stops bouncing quickly, the shocks are fine. If it continues to bounce, they are worn and need to be replaced.
The coil and leaf springs of your suspension will degrade with time. The problem is, when they begin to sag, they can throw off camber (caster, too). In this case, even if you have your mechanic perform a a wheel alignment, the sagging springs may throw camber off again, causing one-sided wear on your tires. Thus, ask your mechanic to check the springs.
The takeaway is that premature tread wear can occur for many reasons. If you notice excessive wearing, invest in a replacement set of tires to preserve your safety and that of your passengers.
