2008 Saturn Astra Owner's Manual - Page 230

9-40 Vehicle Service and Care See your dealer/retailer for details regarding winter tire availability and proper tire selection. Also, see Buying New Tires on page 9-54. If you choose to use winter tires: Tire Sidewall Labeling Useful information about a tire is molded into its sidewall. The examples below show a typical passenger vehicle tire and a compact spare tire sidewall. • Use tires of the same brand and tread type on all four wheel positions. (A) Tire Size: The tire size is a combination of letters and numbers used to define a particular tire's width, height, aspect ratio, construction type, and service description. See the "Tire Size" illustration later in this section for more detail. (B) TPC Spec (Tire Performance Criteria Specification): Original equipment tires designed to GM's specific tire performance criteria have a TPC specification code molded onto the sidewall. GM's TPC specifications meet or exceed all federal safety guidelines. • Use only radial ply tires of the same size, load range, and speed rating as your original equipment tires. Winter tires with the same speed rating as the original equipment tires may not be available for H, V, W, Y and ZR speed rated tires. If you choose winter tires with a lower speed rating, never exceed the tire's maximum speed capability. Passenger (P-Metric) Tire Example (C) DOT (Department of Transportation): The Department of Transportation (DOT) code indicates that the tire is in compliance with the U.S. Department of Transportation Motor Vehicle Safety Standards.