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What’s Up With That? Those Numbers On Tires’ Sidewalls

What are those numbers are numbers on the side of your car’s tires?

Your tires’ age can have a number of effects on your vehicle’s performance and safety. As tires age, they’re more likely to develop cracks inside and outside of them that can harm your control over the vehicle, reduce fuel efficiency, and increase the risk of a blowout. Fortunately, the Department of Transportation (DOT) requires all tire manufacturers to include DOT codes on their tires that provide information about the tire’s age and other factors. 

As you try to assess the condition of your tires and determine when to replace them, it’s essential to understand how to read DOT codes for your and your vehicle’s safety.

What Are DOT Codes on Tires?

DOT codes are standardized tire identification numbers or codes located on both sides of your tire’s sidewall. These codes will always begin with the abbreviation for the Department of Transportation, “DOT,” and the following numbers and letters will provide information on the tire’s manufacturing plant, size, brand characteristics, and age. 

How Do You Decode Tire DOT Numbers? How to Read Your Tire’s DOT Code

If you’d like to check your tire’s DOT code, you can do so fairly easily when you know what each of the numbers and letters means. Below, you can find a breakdown of each part of the DOT code:

  • DOT: Before you begin to read your DOT code, look for the letters “DOT” on your tire’s sidewall. This abbreviation is the beginning of the DOT code and simply stands for “Department of Transportation.”
  • Tire plant code: Once you’ve located the DOT, the next two characters are the tire’s plant code. Typically, these codes contain one number and one letter, and these characters will tell you what manufacturing plant produced the tire. This code can be useful if an alert has gone out about safety issues, tire recalls, or other tire issues. With this code, you can check if your tires have been affected and need to be replaced.
  • Tire size code: After the two-character tire plant code, you’ll see a two-digit tire size code. While these codes used to follow universal tire size codes, the DOT now allows manufacturers to make up their own tire codes. Since tire size codes can vary by manufacturer and are often confusing, it’s usually more convenient to check your vehicle’s tire size by reading your owner’s manual or viewing the tire information on your tire panel, which is located on the door frame of the driver’s side door. 
  • Tire manufacturer characteristics: Following the tire size code are three characters that provide information on the tire manufacturer’s characteristics. Like the tire size code, this code isn’t usually very helpful to drivers, as it often provides brand-specific information that will vary by the manufacturer. 
  • Tire age: When you want to check the age of your tires, the final four numbers in your tire’s DOT code will tell you when it was made. For example, if the last four digits are “1520”, your tire was made in the 15th week — or about April 10 — of 2020. As soon as we pass the 15th week (April 10) of 2025, you want new tires, no matter how thick the tread might be. This code can be especially helpful if you’re not sure how old your tire is and you’re wondering if you need to replace your tires soon.

Does a Tire’s Age Matter? When Should You Replace Your Tires?

Typically, tires last around five years, and the average American drives 13,476 miles per year. Since average tires these days will go about 60,000 miles, the average American will wear out their tread in around four or five years and won’t need to worry about checking their DOT code for the tire’s age. During an annual vehicle inspection, a mechanic can check your tread depth, and if you drive at a rate close to the average American, the mechanic will likely recommend you replace the tires around the four or five-year mark.

While the average driver will likely need to replace their tires every four to five years, some people drive much more than the average and may want tires that can give them 80,000 miles or more of tread life. In this case, they’ll likely want to look for high-mileage tires designed to last longer, and even with these tires, they’ll often need to replace them before four or five years have passed. 

Drivers who don’t drive very often can gain the most value out of checking the final four digits of the DOT code. Since these drivers may not reach their tires’ expected mileage over five years, they might forget to replace them at the five-year mark. Quickly checking the tire age with the DOT code can let them know if five years have passed, and if they have, they’ll want to start thinking about new tires. 

Regardless of a tire’s mileage or tread depth, tires over five years old are at risk of oxidation, which leads to cracks in the tires that put you at a greater risk of a blowout. Due to the high risk of oxidation occurring after five years, tires over five years old should almost always be replaced. 

Choose Chapel Hill Tire for Tire Replacement Services in Raleigh

If you want help decoding your tire’s DOT code or are looking for other tire services in Raleigh, Durham, Chapel Hill, or the surrounding areas, Chapel Hill Tire can help. Our team of certified mechanics is happy to inspect your tires and answer questions you might have about your tires’ age, tread, or driving ability. If an inspection reveals it’s time to get some new tires, our Price Beat Guarantee makes sure you get the best price on exactly the ones you want.Review our selection of tires and tire services today. If you’re ready to bring your car in for tire service, please schedule an appointment at one of our Triangle area locations.

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