2010 Chevrolet Cobalt Owner's Manual - Page 329

If you choose to use winter tires: . Use tires of the same brand and tread type on all four wheel positions. Use only radial ply tires of the same size, load range, and speed rating as the original equipment tires. . Winter tires with the same speed rating as your 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. 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. Passenger (P-Metric) Tire Example (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. 6-57