March 14, 2022 at 12:32 am

This Is What the Codes on Your Car’s Tires Are Telling You

by Matthew Gilligan

Have you ever wondered what all the different numbers and letters on your tires are?

If you have, then you’re in the right place because we’re going to clear up all that confusion today.

There are two different codes you need to pay attention to when you’re looking at tires: the sidewall code and the DOT (Department of Transportation) code.

For the sidewall code, the first letter refers to what kind of vehicle the tire is for. It could be passenger, light truck, special trailer, or temporary (for spare tires).

The second part of the sidewall code is for the tire width and it is the number in millimeters, then a slash mark followed by the tire aspect ratio.

Next is the tire’s construction type, R for radial or D for bias tires.

Then we have the rim size, the load index, and the speed rating for the tires.

The DOT code shows that the tire meets the department’s safety requirements to be allowed on the road and it’s also handy for knowing when the tire was manufactured.

For example, if the last four digits of the DOT code say 1921, it means that the tire was manufactured in the 19th week of the year 2021. It’s as simple as that!

If you want a more visual idea of how to read your tire codes, check out a useful YouTube video by clicking HERE.

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