Reading Your Tire
Now that you know what goes into sizing, rating and constructing each tire, knowing where you can find all this valuable information is bound to come in handy. Luckily, everything you need is conveniently located on the sidewall of every single tire. Understanding it is simply a matter of deciphering the alpha-numeric code used to convey the information. Learn how to locate the size, ratings and other crucial specifications associated with your tire using the following descriptions and illustrations.
The speed rating and load index of the tire are usually listed together directly after the size information, with the load index number stated first and the letter indicating the speed rating last. The maximum load rating, maximum PSI, and DOT number are generally located around the inner edge of the tire along with assorted details about the tire's construction. Uniform Tire Quality Grading information will also be located on the outer edge of the tire opposite of the size.
The most important information on your tire's sidewall is the size. If the tire is a P-Metric tire, the size will begin with a P followed by a three digit number that tells you the section width in millimeters. LT-Metric tires will begin with an LT and Euro-Metric tires will not include any letters but simply start with the section width measurement. The next two-digit number will be the aspect ratio, followed by an 'R' which stands for Radial construction. The final two-digit number will tell you the rim diameter in inches. This sequence is what you will need when trying to match your current tire with a replacement.