What do the numbers on the sidewall mean?
The series of numbers and letters on your tire indicate the type and size of your tire. A P for passengers is common, although LT for light trucks also exists. The next few numbers are the tire's width in millimeters. The next two numbers are the aspect ratio of the sidewall height to the width. Next, you'll see an R for radial, the construction used to make the tire. Next is the rim size in inches. After that is the load rating; the larger the number (up to 125), the more load the tires can take. Finally, the speed rating is T, which is most common with a speed rating of up to 130 mph.