Tire Designations

Tire Size

The following is an example of a typical passenger vehicle tire size.

(A) Passenger (P-Metric) Tire: The United States version of a metric tire sizing system.

(A) Passenger (P-Metric) Tire: The United States version of a metric tire sizing system.

The letter P as the first character in the tire size means a passenger vehicle tire engineered to standards set by the U.S. Tire and Rim Association.

(B) Tire Width: The three-digit number indicates the tire section width in millimeters from sidewall to sidewall.

(C) Aspect Ratio: A two-digit number that indicates the tire height-to-width measurements.

For example, if the tire size aspect ratio is 60, as shown in item C of the illustration, it would mean that the tire's sidewall is 60 percent as high as it is wide.

(D) Construction Code: A letter code is used to indicate the type of ply construction in the tire. The letter R means radial ply construction; the letter D means diagonal or bias ply construction; and the letter B means belted-bias ply construction.

(E) Rim Diameter: Diameter of the wheel in inches.

(F) Service Description: These characters represent the load index and speed rating of the tire. The load index represents the load carrying capacity a tire is certified to carry. The speed rating is the maximum speed a tire is certified to carry a load.

    See also:

    New Vehicle Break-In
    Notice: The vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines: ► Do not drive at any one constant speed, fast or slow, for t ...

    SERVICE BRAKE ASSIST
    This message may be displayed when there is a problem with the brake boost assist system. When this message is displayed, the brake boost assist motor might be heard operating and you might ...

    When to Check and Change Automatic Transmission Fluid
    A good time to check the automatic transmission fluid level is when the engine oil is changed. Change the fluid and filter at the intervals listed in Scheduled Maintenance and be sure to use th ...