What do the sidewall markings on my tire mean?
The sidewall markings on a tire provide descriptive information about the tire's design. The following refers to the tire illustration below with the sidewall marking of 225/50R16:
  • 225 - This number specifies the width in millimeters (i.e. 225 mm)
  • 50 - This number is the Aspect Ratio, the ratio of sidewall height to width
  • R - Radial
  • 16 - This number designates the tire's diameter in inches (i.e. 16")
  • 92 - This number indicates the tire's load-carrying capacity, known as the Load Index; as the number for the load index increases so does the load-carrying capacity (All passenger car tires in the U.S. are also marked with their actual load limit in pounds)
  • V - This letter denotes the Speed Rating, the maximum tire speed under controlled test conditions ("V" in this example is one of several types of speed ratings)
  • psi (pounds per square inch) - The maximum cold inflation rating for the tire
  • DOT (Department of Transportation) - This symbol indicates the tire meets or exceeds United States DOT safety standards; the letters and numbers following the DOT symbol provide information about the tire manufacturer, tire size, and the date it was manufactured