According to the recommendations of tire manufacturers, tires should be replaced every six to ten years, but how do you know for sure that it is time to replace your tires?
1. Penny Test: In the U.S., the tread depth of a tire is measured in 32nds of an inch, and a new tire’s tread is typically between 10/32 and 11/32 inches. The U.S. Department of Transportation recommends that tires should be replaced a 2/32 inches. One common test is to determine the depth of your tire’s tread by using a penny. Place the penny with Lincoln’s head down in the tread. If the tread covers the whole head, it is still ok. If you can see the whole head, it has reached the 2/32 mark, and the tire should he replaced.
2. Tread Indicator Bars: Another way to determine tread depth is to check the tread indicator bars that come on newer tires. These bars are embedded in the tire at 2/32 inch, so if the tread is even with these wear bars, it is time to replace your tires.
3. Check the Sidewalls. Look for cracks or cuts could be indicative of a possible tire failure waiting to happen.
The Age of the Tire
Older tires can be a safety threat. If you purchase a used car, or decide to save money by buying used tires, your tires may be much older than they look, and can pose a significant safety threat. Even seemingly new tires with perfect treads, that have never been used on the road, can be dangerous if they are old.
An an illustration of this fact is the accident that killed actor Paul Walker. The California Highway Patrol and the LA Times reported that the car he was riding in had nine-year-old tires, and that the age of the tires may have affected the ability of the driver to control the car.
In another instance, in need of a new tire for his SUV, the owner tried to save money by buying a used one. While he was driving his car, the tread separated from the tire, causing him to lose control and hit a motorcycle, killing the driver. When the tire was inspected, it was determined that the tire was almost 10 years old.
These examples emphasize the fact that the age of the tire can affect it’s safety. The tread on the tires can look fine, and pass the simple tests, but sometimes the actual age of the tire can present an unseen problem. This is because the rubber compounds from which the tires are constructed deteriorate with age. Sean Kane, president of Safety Research and Strategies, Inc., explains it this way: “If you take a rubber band that’s been sitting around a long time and stretch it, you will start to see cracks in the rubber.” The same thing happens to a tire over time. To see an animation of this process and how it happens, go to the company’s website: www.safetyresearch.net.
Determining the Age of the Tire
There a several methods to determine the age of your tires. The simplest and most obvious method is to look at your receipt, but if you don’t have or can’t find your receipt, what can you do?
Here is one method that many people do not know about: examine the DOT number. When you purchased your last set of tires, you may have noticed a series of numbers on the sidewalls. Perhaps you did not think these numbers were significant, but they will show you important information about your tires that you need to know. The Department of Transportation requires that the tire manufacturer place the following information on the tire: the manufacturer’s code, the tire size and the week, year and place where the tire was manufactured.
On a newer car, (from 2000 to present) this information is easy to obtain. Look for the letters DOT and examine the numbers that follow. For example, if the numbers are 0308, the tires were manufactured in the third week of 2008. However, if your tires were made before the year 2000, it gets more difficult. On these tires, the numbers038 mean something more confusing. These tires were made in the third week of the year and the eighth year of the decade. There is no way to find out WHICH DECADE?? (The tires could have been made in l988 or l998.)
How Long Should My Tires Last?
There are differences of opinions between the manufacturers of automobiles, tires and rubber products as to how long a tire will last. The National Highway Traffic Safety Administration (NHTSA) has no guidelines on this subject, but allows car and tire manufacturers to make their own recommendations. This is because the life of the tire depends on storage, environmental conditions and how the tire is used. For instance, warm weather and coastal climates can make the tire deteriorate more quickly. Rough roads and lots of cornering can wear out tires faster too.
Recommendations for Tire Safety:
1) Check tires often for signs of aging, such as cracks in the sidewall or distortion of the tread.
2) Replace tire immediately if you notice vibrations, or other changes in the performance of the tire.
3) Don’t buy used tires, and when buying new, make sure you are getting an actual new tire, not an older, unused one.
4) Follow your tire dealer’s recommendation to have a five-year safety check-up, and get new tires if it is determined that you need them.
Your tires are perhaps the most important part of your driving safety as they have a significant effect on how your car handles. If you need new tires, don’t wait. Your life and others may depend on it.