How to read tire size from sidewall

You call, looking for a price on tires or maybe even brakes. The attendant on the phone asks you for your tire size. You don't have any ideas. All you know about your tires is that they are black and round and spin when you step on the gas. Where do you even find this information?

Here is an easy way to determine the tire size from the tire sidewall:

Find a number structure like this example: P215 / 60R16. It will run along the outside of the side wall. It may be at the bottom of the tire, so you may have to read it upside down.

The prefix "P" indicates the type of tire service. P is a passenger tire. Other common types are LT for light truck use, T for temporary use as spare tires, and ST for special trailer use only.

• First number, 215, is the tire tread width, measured in millimeters.

• The number after the slash, 60, this is the tire profile. The profile is the height of the tire from the ground to the rim, measured as a percentage. In this example, the tire height is 60 percent of the tire width.

• The next letter R, indicates the type of tire construction. R is a radial tire. Another option, although less common, is ZR, which indicates that the tire is designed for high speeds.

• The last number in the sequence, 16, indicates the tire rim size, measured in inches.

Other tire designs have historically been used and are no longer common. D stands for Bias Construction or Bias Ply and B stands for belted tires. Both designs are extremely rare to see on modern tires.