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Tire Inspection Guide: How to Check Tire Tread & Tire Pressure

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With everything that’s going on in the world right now, tires are probably the last thing on your mind. After all, let’s face it—tires are pretty boring. And yet, they are one of the most important parts of your car. That’s why, in honor of National Car Care Month, we want to encourage you to take care of your tires.

Tires affect several different aspects of vehicle operation, including braking ability, handling, and traction characteristics. Even fuel economy can take a dive if your car’s tires aren’t well maintained. As such, most experts recommend inspecting your tires at least once a month.

You probably already know to check the tire pressure and tread depth regularly. But that’s not all. There are a few often overlooked aspects of tire care that you should consider as well.

How to Properly Inspect Your Tires

Finally, you’re able to take a break from your busy schedule to check your car’s tires. Here’s what you need to know to do the job right.

Get to Know Your Car’s Tires

Before you do anything else, take a few moments to get to know your car’s tires. It’s helpful to understand details, such as the tire size, DOT number and recommended inflation pressure.

Tire Size, Load Rating, and Speed Rating

You’ll find the tire size, load rating, and speed rating listed on the sidewall. Let’s take a look at an example to gain a better understanding. 

tire size numbers on sidewall
 Example tire size: P205/55R16

After the tire size, you’ll see two more numbers and a letter (for example, your tire might read 91H). The numbers are the tire’s load rating, while the letter is the speed rating. 

Charts that define both values are available and can be easily found online. You can also check out our article on tire speed rating and tire load index.

tire sidewall numbers

Department of Transportation (DOT) Number

Following the load and speed ratings, you’ll find the department of transportation (DOT) code. In a nutshell, the twelve-digit code is used to signify that the tire complies with certain safety standards.

Although the DOT code doesn’t seem like it would be of much interest to car owners, the last four digits are actually quite important. On all vehicles built after the year 2000, the final four numbers in the code indicate the tire’s manufacture date and, therefore, its age.

The first two digits of the code denote the week, while the last two digits signify the year. For instance, if the final four digits of the code are 4517, that means the tire was manufactured during the 45th week of 2017.

Correct Tire Pressure Rating 

Determining the correct inflation pressure for your tires is easy. Inside the driver’s side door jamb, you’ll find a placard that lists the pressure specifications. In many cases, the data decal, which is also located in the door jamb, will list the information as well. You can also find the recommended tire pressure in your owner’s manual.

Tire placard lists the pressure specifications
The data decal, which is also located in the door jamb, will list the information as well.

Note: Do NOT inflate a tire to the rating on the sidewall; that is the maximum pressure the tire can withstand.  

Perform a Visual Inspection

Now that you’re fully acquainted with your tires, it’s time to move onto a visual inspection. Start by checking each tire for problems, such as separation, cracks, bulges, and missing chunks of rubber. 

If you find any of these issues, replace the tire immediately.

It’s also a good idea to check for “cupping” by running your hand across the tire tread. Cupping, which is a series of high and low spots in the tread, is usually the result of worn shocks or struts.

And one more thing: As was mentioned, you can determine a tire’s age by looking at the last four digits of its DOT code. If the code indicates that your tires are more than 10 years old, it’s time to purchase a new set of rubber.

Measure the Tread Depth

Many sources recommend using a penny to check a tire’s tread depth. And while that method works in a pinch, it’s not very thorough or accurate. 

That’s why using a dedicated tread depth gauge is a much better idea.  

Using a tread depth gauge on each tire is a straightforward affair. Here’s how it’s done:   

It’s time to consider purchasing new tires if the gauge reads between 3/32” and 4/32”. Tread that measures 2/32” or less means you should replace the tires immediately.

Check the Pressure

Proper tire inflation is of utmost importance. Underinflated tires experience accelerated wear, while also reducing fuel economy and increasing the risk of a blowout. Overinflation can also increase the risk of tire failure. 

Both scenarios can reduce your car’s braking, handling, and traction abilities.  

Even if your car has a tire pressure monitoring system, it’s a good idea to check the pressures yourself with a tire pressure gauge.

Here’s how it’s done:

Tire Maintenance is Key  

Like everyone else, you want your car to provide a safe, dependable driving experience. And proper tire maintenance will help make that happen. So, don’t wait for National Car Care Month to roll around again next April. Put a note in your digital calendar, reminding yourself to take a peek at your tires regularly.


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Author

Mia Bevacqua

Chief Mechanic at CarParts.com

Mia Bevacqua is an automotive expert with over 15 years of industry experience. She holds ASE Master, L1, L2, and L3 Advanced Level Specialist certification, as well as a bachelor's degree in Advanced Automotive Systems.

Throughout her career, Mia has applied her skills toward automotive failure analysis inspections, consulting, diagnostic software development, and of course, freelance writing. Today, she writes for companies around the world, with many well-known clients showcasing her work.

Mia has a passion for math, science, and technology that motivates her to stay on top of the latest industry trends, such as electric vehicles and autonomous systems. At the same time, she has a weakness for fixer-upper oddballs, such as her 1987 Chevy Cavalier Z-24 and 1998 Chevy Astro Van AWD.

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