2007 Subaru Impreza Owner's Manual - Page 358

13-2 Consumer information and Reporting safety defects For U.S.A. The following information has been compiled according to Code of Federal Regulations "Title 49, Part 575". Tire information & Tire labeling Many markings (e.g. Tire size, Tire Identification Number or TIN) are placed on the sidewall of a tire by tire manufacturers. These markings can provide you with useful information on the tire. ! Tire size Example: Your vehicle comes equipped with P-Metric tire size. It is important to understand the sizing system in selecting the proper tire for your vehicles. Here is a brief review of the tire sizing system with a breakdown of its individual elements. ! P Metric (1) P = Certain tire type used on light duty vehicles such as passenger cars (2) Section Width in millimeters (3) Aspect Ratio (= section height 7 section width). (4) R = Radial Construction (5) Rim diameter in inches ! Load and Speed Rating Descriptions With the P-Metric system, Section Width is measured in millimeters. To convert millimeters into inches, divide by 25.4. The Aspect Ratio (Section Height divided by Section Width) helps provide more dimensional information about the tire size. The load and speed rating descriptions will appear following the size designation. They provide two important facts about the tire. First, the number designation is its load index. Second, the letter designation indicates the tire's speed rating.