Tire Ratings And Sizes

Anybody who is unfamiliar with the way tires are rated will be confused when confronted with them for the first time. How do you know what a P275/75/R15 tire is?

In this article I’ll show you how you can understand what ratings mean and how they can differ between style and brand.

Various cars will need various tires. LT stands for light truck while P stands for passenger.

Width Of Tire Depending upon how wide your tires are, they will alter the way your car or truck handles and how efficiently it uses fuel, as well as other things. The width of each tire will be added in millimeters, each inch is around 25.4 mm, for your reference. The following example is around 10.8″ in width.

The Aspect Ratio This is written as a ratio with the width of the tire, it stands for how tall the tire is from the tread to the mount. In the following example the tire is around 75% compared to how wide it is.

Build How your tire is built is crucial. If the tire is reinforced to increase its life and strength it will be labeled as R, which stands for radial construction.

Diameter Of The Rim This stands for how big the wheel is. When buying a tire it needs to have the same diameter as your wheel has. The following example has tires with a diameter of 15.

Now that you know what everything means, you can tell that a P275/75/R15 tire means it is a Passenger tire with a width of 275 millimeters which is around 10.8 inches, the aspect ratio equals 75% and is a tire made from radial construction to fit on a wheel that is 15″.

What do the speed ratings mean? Tires will have a speed rating starting from 100mph and increasing. Considering the speed limit stays under 75mph you shouldn’t worry too much about the speed rating of your tire. However for those with a faster car you may want to consider this aspect of your tires.

You should also consider the UTQG (Uniform Tire Quality Grading) number which is written within the inner sidewall of a tire. This number represents how well it performs in areas such as resistance to temperatures, traction and treadwear. The US sets the standard requirements and these ratings are compared to various control tests. The NHTSA (National Highway Traffic Safety Administration).

When comparing these numbers you will get a good idea how good the tire is in relevance to its traction, so how well it can stop on various surfaces, how well it resists certain temperatures and it’s treadwear, which compares how long it should last if you drive regularly and without doing anything crazy.