How To Tell When You Need To Replace Your Tires

Cat and Car Tire
Photo Credit: RonaldPlett

For many people, they rarely think about their tires unless they get a flat tire. Then it becomes a major inconvenience. Instead of ignoring our tires until there is a problem with them, we need to pay more attention to the condition of the tires that are on the car because we have a lot riding on them. I’m not talking about the car itself. Cars are replaceable, but your life and your family’s aren’t.

You do not need to be a mechanic or go to a mechanic to determine whether your tires need to be replaced. Anyone can check their tires in 5 minutes to see whether their tires are worn with no special tools needed. It’s so simple that this can be done while you are at the gas station fueling up your car.

Minimum Tire Tread For Maximum Safety

The U.S. Department of Transportation recommends replacing tires when they reach 2/32”. What does 2/32” look like? Beats me. Luckily, there are two easy ways to see whether you’ve reached the 2/32” threshold. All you need is a penny or to look for the tread wear indicators.

Tire Penny TestThe Penny 2/32″ Test

To perform the penny depth test, take a common Lincoln penny that no one usually ever wants and place it upside down into the groove between the tread blocks. If you can see the top of Honest Abe’s head, then your tires are at the 2/32″ limit and you should look into replacing them soon. It’s that simple.

The Tread Wear Indicators

Looking for the tread wear indicators is a little more involved. You will need to look on the edge of the tread on the tire for markings showing where the tread wear indicators are located. For many tires, they will use a triangle. Others, like Michelin tires, will have the Michelin Man figure molded into the tire. Once you’ve located the marking for your tire, look closely across the tire in between the grooves at that spot. You’ll notice raised bars in the grooves. When these bars are flush with the top of the tread, you are at the wear limit.

Bridgestone Tire Tread Wear Indicator
Photo Credit: Good Money Sense
Tire Tread Wear Bars
Photo Credit: MikesPhotos

Using A Tread Depth Gauge

Now if you want a better estimate or faster evaluation of your tire’s life, you can spring for a tire tread depth gauge from your local auto parts store. With the depth gauge, all you have to do is stick the probe into the tire groove and press the shoulders against the tread block and read the results. Some like this Steelman Tread Depth Gauge even has color-coding in addition to the measurement numbers for quicker identification.

While 2/32” is considered the legal minimum tread depth for tire replacement, Consumer Reports have found that the stopping distance from 70 mph at 2/32” during wet braking was nearly double that of a car equipped with new tires at 379 feet versus 195 feet. This is due to the deeper grooves being able to channel away more water on the road. Not only do the deeper grooves help you stop faster, you are less likely to hydroplane. If you anticipate a lot of driving in adverse conditions such as in rain, sleet, and snow, Consumer Reports and Tire Rack recommends replacing your tires earlier at 4/32”.

Quarter Tread Test 4/32The Quarter 4/32″ Test

To perform a quick depth test for tread at 4/32”, leave the penny in your pocket and pull out a quarter. When you stick the upside down quarter into the groove between the tread, if you can see the top of Washington’s head, then it is time to replace your tires because George never lies.

Pay Attention To Tire Age

After the amount of tread left on your tires, the next thing you need to pay attention to on whether your tires need to be replaced is the age of your tires. Just like how an old rubber band develops cracks, tires age and develop dry rot. This could eventually cause the steel belts within the tire to separate and the tire to fail when you are driving.

Even if an old tire doesn’t fail, old rubber isn’t as sticky as new tires as it dries out. The LA Times reported that CHP investigators found that the Porsche Carrera GT that crashed and killed Paul Walker and his friend had tires that were nine years old. In their report, they noted that due to the old tires, the “driveability and handling characteristics of the car may have been compromised”.

To figure out how old your tires are, look on the sidewall for the DOT symbol. The last four numbers at the end of the tire identification letters and numbers will be the date of manufacture. The first two numbers is the week and the last two numbers is the year. In the below example, that tire was made on the 26th week in 2013.

DOT Tire Information
Photo Credit: NHTSA

Most car manufacturers and tire makers recommend that tires be inspected or replaced after six years. Continental and Michelin say that tires manufactured more than ten years ago should be replaced.

For the average person who drives 12,000 to 15,000 miles a year, age usually isn’t a problem since they’ll likely wear out the tire’s tread first.

Even if you drive enough miles to not give a second thought about the age of the tire, you should still know how to check the age of the tire. Once the tire leaves the mold, the clock starts ticking. The last thing you would want is to pay for a brand new tire that has been sitting on the shelf for four or more years.

Knowing how to determine the age of your tire is also important if you own a weekend car, a secondary or recreational vehicle that you don’t drive regularly, or have a spare in your trunk or under your truck.

Other Considerations

Heat: NHTSA research has found that tires age more quickly because of heat and sunlight. If you live in the southern states, you’ll want to check your tires earlier for signs of dry rot and cracking in the rubber. The same should be done for your spare if it’s stored in your trunk.

Tire Inflation: Driving on under-inflated tires results in higher tire temperatures causing them to overheat because of additional friction from too much tire on the road. This increases the chance of blowouts. Tire Rack estimates that under-inflated tires’ tread life could be reduced by as much as 25%. Plus, you’ll get worst gas mileage. Luckily, all new cars are required to have TPMS sensors now to let you know if your tire pressure is way too low.

Pick up a cheap tire pressure gauge and keep it in your glove box and check your tires regularly. On the motorcycle, I go as far as to check them before each ride because I only have two tires.

Uneven Wear: If you have not been keeping up with your tire rotation schedule, you may need to replace your tires sooner than expected. On front wheel drive cars, the front tires are responsible for most of the acceleration, braking, and steering and will wear faster than the rear tires. If you car is out of alignment, your tires may also wear faster on one edge.

Used Tires: Beware of buying used tires. They may be cheaper, but you will not know its history. You don’t know whether the previous owner likes to home in on the potholes in the road or has driven over one too many curbs.

Closing $ense

Yes, tires are expensive. While we would prefer to drive until the steel belts are showing, that isn’t worth the risk of one of your tires failing in rush hour traffic.

As you are driving down the road, the contact patch of most passenger tires are about the size of your hand. And those tires need to hold up the weight of your car and the forces of bringing your car to a stop from 65+ mph. Knowing this, any extra 1/32″ of tread available to stop your two ton car in a panic situation counts.

When was the last time you checked the condition and air pressure of your tires?

6 thoughts to “How To Tell When You Need To Replace Your Tires”

  1. My tires have been squealing when I turn corners, so I think I may need to get them replaced. Thanks for mentioning that I’ll want to make sure I rotate my tires regular, as not doing so can cause uneven wear. Do you have any tips for finding a great tire service in my area?

    1. Glad to have helped, Taylor. As for a great tire service, I’d look at Discount Tire, Kauffman Tire, and Costco. All three offer free rotation for the life of your tire if you buy your tires from them. Discount Tire and Kauffman Tire also will plug tires for free even if you didn’t buy your tires from their store.

  2. It’s good to know that old tires can dry out. I didn’t realize that they aren’t as sticky as new tires. That’s definitely a good thing to look for when you need new tires.

  3. I’m glad that you talked about how manufacturers want you to replace your tires every six years. My son recently bought his first used car. He has added a few cool aftermarket parts on it and I think he’s pretty happy with the purchase. The vehicle would turn five years old this year if I am correct, so I’ll be sure to share this article with him so he can consider visiting a nearby tire shop to have a look at his best options for a new set of tires.

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