2014 Chevrolet Silverado 1500 Extended Cab Owner Manual - Page 424
2014 Chevrolet Silverado 1500 Extended Cab Manual
Page 424 highlights
10-60 Vehicle Care (3) 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 tire illustration, it would mean that the tire's sidewall is 75 percent as high as it is wide. (4) 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. (5) Rim Diameter : Diameter of the wheel in inches. (6) 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. Tire Designations Tire Size The examples show a typical passenger vehicle and light truck tire size. Light Truck (LT-Metric) Tire Passenger (P-Metric) Tire (1) 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. (2) Tire Width: The three-digit number indicates the tire section width in millimeters from sidewall to sidewall. (1) 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 mean a light truck tire engineered to standards set by the U.S. Tire and Rim Association. (2) Tire Width: The three-digit number indicates the tire section width in millimeters from sidewall to sidewall.