2014 Cadillac ATS Owner Manual - Page 330

10-44 Vehicle Care performance factors: treadwear, traction, and temperature resistance. For more information see Uniform Tire Quality Grading on page 10-59. (7) Maximum Cold Inflation Load Limit: Maximum load that can be carried and the maximum pressure needed to support that load. (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. (3) 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 3 of the illustration, it would mean that the tire's sidewall is 60 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 manufactured date. The first two digits represent the week (01-52) and the last two digits, the year. For example, the third week of the year 2010 would have a four-digit DOT date of 0310. (4) Tire Identification Number (TIN): The letters and numbers following the DOT code are the Tire Identification Number (TIN). The TIN shows the manufacturer and plant code, tire size, and date the tire was manufactured. The TIN is molded onto both sides of the tire, although only one side may have the date of manufacture. (5) Tire Ply Material : The type of cord and number of plies in the sidewall and under the tread. (6) Uniform Tire Quality Grading (UTQG): Tire manufacturers are required to grade tires based on three Tire Designations Tire Size The following is an example of a typical passenger vehicle tire size.