2010 Cadillac CTS Owner's Manual - Page 360

9-60 Vehicle Care (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. Passenger (P-Metric) Tire Example Summer Performance Tires Many General Motors high performance models come factory-equipped with tires that are optimized for maximum dry and wet road performance while still retaining satisfactory tread life, excellent durability, and low noise levels. In severe winter climates where snowfall may be significant, these tires may be found to provide less traction. 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. (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. (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. (D) Tire Identification Number (TIN): The letters and numbers following the DOT (Department of Transportation) code is the Tire Identification Number (TIN).