2006 Saab 9-3 Owner's Manual - Page 265

Car care Uniform Tire Quality Grading (UTQG): Tire manufacturers are required to grade tires based on the performance factors: treadwear, traction and temperature resistance. For more information see "Uniform Tire Quality Grading" on page 261. Maximum Cold Inflation Load Limit: Maximum load that can be carried and the maximum pressure needed to support that load. For information on recommended tire pressure see "Recommended lowest tire pressure, cold tires" on page 306 and "Loading Your Vehicle" on page 267. 265 Tire Size The following illustration shows an example of a typical passenger car tire size. 215 / 55 R | a a b c d e f | b | c 16 93 | d | e H | f Tire Width Aspect Ratio Belt Rating Rim diameter Load range Speed rating Tire Width: The three-digit number indicates the tire section width in millimeters from sidewall to sidewall. Aspect ratio: A two-digit number that indicates the tire height-to-width measurements. For example, if the tire size aspect ratio is "55", as shown in item "C" of the illustration, it would mean that the tire´s sidewall is 55% as high as it is wide. Belt Rating: 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 beltedbias ply construction. Rim Diameter: Diameter of the wheel in inches. Load range: The load range represents the load carry capacity a tire is certified to carry. Speed Rating: The maximum speed that a tire is certified to carry a load. Speed ratings range from "A" to "Z".