By Tire Agent Staff
December 06, 2021
Image source: Bridgestone
How do you know when you need new tires? This article explains how to know when it's time to replace your tires based on how old your tires are, how many miles, and a number of other factors.
The answer to how often you need to replace your tires depends on a bunch of things:
The real question, though, is how to tell when and if your tires need to be replaced, which is what we cover next.
Tire age limit is typically 6 years from the date it was manufactured. To find the tire date code, look at the sidewall of your tire. All US tire manufacturers are required to stamp the date on the tires, so you can see them.
As we explain in “Tire Number Meanings,” every tire sold in the United States has to follow DOT tire age laws. The US Department of Transportation requires tire makers to mark all tires with the week and year the tire was made. To find your tire's "birthday," look for the DOT marking. The last four numbers represent the tire manufacturing date.
For example, a tire marked DOT CPEX 3ET 0318 was made in January (third week) of 2018.
Tires will dry and rot faster if they sit for a long time in one position, under the weight of a vehicle, exposed to weather, and aren’t driven. For people who live in hot and dry climates, the risk for cracking and sidewall weathering is even greater.
It’s also important to keep your tires properly inflated, so they last as long as possible. Driving on overinflated or underinflated tires is not only dangerous, but it’s also bad for the rubber. Tire pressure guides are typically published on a sticker on the inside of the driver’s door. You can also find them in your owner’s manual.
Typical new tires have a tread depth of 10/32 of an inch (10/32”) but some mud tires, all-terrain tires, and off-road tires have deeper depths closer to 15/32”. The standard depth for replacing tires is before the depth reaches 2/32” — at 2/32” or lower, the tire is bald and dangerous.
You can buy a tire tread depth gauge for under $10 from any auto supplier, or you can use the coin test.
The coin test uses a Lincoln penny to measure a tire’s depth. The rule says: Place a penny Lincoln-head-down in the groove of a tire and, if Honest Abe’s head disappears, your tread depth is deep enough for safe driving. However, if you see the top of his head, you’re less than 2/32” of an inch, and it’s time to replace those tires.
Here’s the rub: Do not check just one spot of the tire. Run it along several inches of the tire, because tires can wear unevenly, depending on your vehicle, driving style, and terrain. If any part of the tire is worn, it’s time to replace it.
Newer car models have built-in tire pressure monitoring systems (TPSM) that alert drivers when their tires are underinflated. If you see this light, you need to check your tire pressure. If it is low, fill the tire to the manufacturer’s recommended pressure.
How many miles should a tire get? A manufacturer’s warranty is a slight indication to how long tires are expected to last, in terms of miles. The honest answer is, there is no way to tell how many miles you will be able to drive on a tire.
How do you know when you need new tires? Do not go solely by mileage when deciding when it's best to change your tires. Follow these simple rules:
According to most manufacturers, and even the law in most areas, your tires should be replaced when the tread depth reaches 4/32” in the winter and 2/32″ in the summer. If your tread depth wears to those levels, your tires are considered bald and a safety hazard.
The same rules for checking tread depth apply to winter tires as they do for all vehicle tires. However, you should replace winter tires when they are half worn, long before they wear to 2/32”. Why? Winter tire treads are designed to get you safely through slush, snow and ice. Their deep grooves are engineered to push snow and slush away from your vehicle, so you don’t slip and slide.
By the way, to avoid dry rot and get the most from your winter tires, during the off season, store your tires in a cool, dark and dry place, not outside where they are exposed to the elements.
Apply the same tread depth standards to your summer tires as you do for the three-season or all-season tires. When tread depth gets below 4/32” start shopping for tires. Follow the same storage rules as you would for any tire — store them inside if possible, protected from weather conditions.
All-terrain and mud tires need much more than 2/32” to be effective, and because they’re built for off-roading, they might wear unevenly. While the rule says 2/32”, we advise replacing mud and all-terrain tires when they are at about 50% wear. So, if the tire measured 15/32” when it was new, you should start shopping for replacements when they wear to about 7/32”.
Modern tires have a built-in indicator that tells you when it’s time to replace them. They’re called wear bars, and they are little tread marks that are placed throughout the tires at approximately 2/32 of an inch, which is the hazard point of a tire. Learn more about tire wear bars.
Source: Cooper Tire
To extend the lifespan of tires on cars, do these things: