The numbers on tires indicate important information about the tires type, width, aspect ratio, construction type, diameter, load index, and speed rating. Here is a breakdown of what each number means:

• Tire type letter: The first letter in the code tells you what class of tire it is.
• Tire width: The three numbers following the tire type letter represent the width of the tire in millimeters measured from sidewall to sidewall.
• Aspect ratio: The forward slash separates the tire width number from the two-digit aspect ratio. The aspect ratio is the height of the tires sidewall as a percentage of the tires width.
• Construction type: The tire letter meaning refers to the construction of the tire: R for radial, D for diagonal, and RF for run-flat.
• Wheel diameter: This two-digit number specifies wheel diameter in inches.
• Load index: Load index is a two or three-digit number following the two-digit wheel diameter number. It tells you how much weight the tire can safely support. Load index ranges from 0 to 150, with most tires designed for passenger vehicles ranging from 75 to 100.
• Speed rating: Speed rating is the last letter in the tire code and indicates the top speed a tire is designed to ride.

Understanding these numbers is important for selecting the right tire for your vehicle and driving needs.