What Is All That Writing on the Tires? — Titan Auto & Tire

More Than You Anticipated

You need a set of tires. When you’re ready to make the purchase, you discover a lot of writing on the tires. What does all that jargon mean? This is more than you anticipated! A tire is a tire, right? Not exactly. The specifications of each tire are spelled out on its sidewall. For an explanation and help choosing the right rubber for your vehicle, count on Titan Auto & Tire for tire sales and related services.

You Need a Tire. What’s All That Other Stuff?

A tire is not a single entity. Although the sidewall may initially seem confusing, it actually displays a lot of useful and necessary information that helps you know exactly what you need to buy. The abbreviations allow a lot of information to be displayed succinctly in a tiny area. Further, the markings ensure that facts about industry safety standards required by the US Department of Transportation (DOT) can be displayed for anyone who needs to access the information. For instance, the first letter indicates the tire class. European metric tires leave this off, but US tires show a P for passenger cars and LT for light trucks. Next, a 3-digit number tells the width of the tread in millimeters (mm) from sidewall to sidewall. A mark of 225 means that the tread is 225 mm across. Afterward, digits followed by an R tell you the aspect ratio, the relationship between tread width and sidewall height expressed as a percentage. Thus, a 45 R tire has a sidewall height that’s 45% of the tread width.

A letter from A to Z comes next, denoting the speed rating. That’s the highest speed the tire can safely reach if it’s in prime condition. Available reference charts show the range for each letter. Z is the highest such rating. (Note: Z range tires also have W and Y indicators to give a more realistic maximum safe operating speed.) If an R is then present, the tire is a radial. This variety is made with layers of cords. The diameter is expressed by the next 2-digit number. An 18, for instance, tells you that the diameter is 18 inches. How much the tire can carry, known as the load index, is the next multi-digit display. The final letter is the operational speed rating. Other required DOT marks prove the manufacturer’s plant location, tire size, and production date. The tread pattern may also be noted, and weather and durability information can be found in the Uniform Tire Quality Grading (UTQG) mark. The maximum inflation amount is given by the PSI.

Your Local Go-To Tire Shop

If this all still seems a bit much, don’t worry. The professionals at Titan Auto & Tire are here to help you. Customer service is one of our highest priorities, and you can count on us for tire sales as well as all related repairs and services.

Written by Titan Auto & Tire