Tire Size

The following examples show the different parts of a tire size.

(A) Passenger (P-Metric) Tire: The United

(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.

(A) Light Truck (LT-Metric) Tire: The United States version of a metric tire sizing system. The letters LT as the first two characters in the tire size means a light truck 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 75, as shown in item C of the light truck (LT-Metric) tire illustration, it would mean that the tire’s sidewall is 75 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: The service description indicates the load range and speed rating of a tire. The load index can range from 1 to 279.

Speed ratings range from A to Z.

    See also:

    Keys
    CAUTION: Leaving children in a vehicle with the ignition key is dangerous for many reasons. They could operate the power windows or other controls or even make the vehicle move. The children or ...

    How to Wear Safety Belts Properly
    This section is only for people of adult size. There are special things to know about safety belts and children. And there are different rules for smaller children and infants. If a child will be ...

    Ignition Transmission Lock Check
    While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position. The ignition should turn to LOCK/OFF only when the shift lever is in P (Park). ...