How To Read Tire Size
There’s a lot to read on the side of your tires. Letters, numbers, codes, and ratings… it’s no wonder the average driver has trouble making sense of it all. But don’t worry, in this post, our team at MINI of Manhattan is clearing the air once and for all, and explaining what all those markings on the side of your tires mean. If you’re still a little lost after reading the article below, and you’re in the Manhattan, Bronx, or Queens areas, give us a call at our service center and we’ll be happy to help you out.
Tire Size and Ratings
When trying to understand the tires’ size and ratings, most people are looking at the class, width, height, tire type, wheel diameter, load capacity, and speed rating. Here’s an example:
In the example above, P stands for Passenger Car and represents the tire’s class. You might also see LT here instead, which stands for Light Truck.
The following number, 215 in our example, is the width from one sidewall to the other in millimeters; also known as the section width. Next to that is usually the aspect ratio, represented as a percentage (65 in our example above). This is the height of the sidewall in relation to the section width. In other words, the height of the sidewall in our example is 65% of the tire’s width from sidewall to sidewall.
The R next to the aspect ratio stand for Radial which is the type of tire. In fact, radial tires are the most common type of tires on the road thanks to their durability and versatility. The 15 following the tire type in our example, is the wheel size that this specific tire will fit on. So, our example tire will fit on a wheel with a diameter of 15 inches.
Finally, you have the load index (95) and the speed rating (T). The load index represents the maximum load capacity of the tire. Meanwhile, the speed rating specifies the maximum speed the tire can be driven on. There are many ratings, but S, T, and Z are the most common. However, when a rating of Z is given, you’ll also get a rating of either W or Y, since Z simply means a speed rating higher than 149 MPH.
- L = 75 MPH
- M = 81 MPH
- N = 87 MPH
- P = 93 MPH
- Q = 99 MPH
- R = 106 MPH
- S = 112 MPH
- T = 118 MPH
- U = 124 MPH
- H = 130 MPH
- V = 149 MPH
- Z = over 149 MPH (shows in combination with W or Y rating)
- W = 168 MPH
- Y = 186 MPH
Additional Tire Markings
While the tire sizes and markings listed above are the most commonly referenced, there are also markings for the U.S. Department of Transportation (DOT) and Uniform Tire Quality Grading (UTQG) on your tire. The DOT code gives information about the manufacturer of the tire, as well as when and where the tire was made.
The UTQG markings on the other hand give ratings for treadwear, traction, and temperature resistance. These ratings are given based on tests conducted by the manufacturer under the UTQG guidelines. Because of that, there is some room for interpretation here especially when it comes to treadwear. It’s good to use these grades when comparing tires from the same manufacturer, but might not be as helpful when comparing tires from different manufacturers.
Have a question about how to read tire size?
Give us a call! Our team at MINI of Manhattan is here to help drivers from across the Manhattan, Bronx, and Queens areas. If you’re not sure what tires you have or what tires you need, our certified technicians can help.