What does my tire size mean?
- The first three numbers of a tire size measures the width in millimeters from sidewall to sidewall.
- If the tire size is 255/60 R16, the width of the tire is 255 millimeters.
- The two digit number after the slash mark is the aspect ratio which measures the tire’s cross-section to it’s width.
- If the tire size is 255/60 R16, the 60 means that the height is 60% of the tire’s width. The bigger the aspect ratio, the bigger the tire’s sidewall will be.
- In between the Aspect Ratio and Rim Diameter, is the construction of the tire.
- If the tire size is 255/60 R16, the “R” stands for Radial, which means the layers of the tire run in straight lines across the tire.
- If there is a “B” instead of an “R” listed on your tires, the “B” stands for Bias construction which means the layers run diagonally across the tire.
Wheel Size (Rim Diameter)
- Located after Construction is the wheel size, which tells us the size of the wheel/rim that the tire is intended to fit and is measured from one end of the wheel to the other.
- If the tire size is 255/60 R16, the 16 means that the wheel is 16″ in diameter.
- To support the weight of the vehicle, each tire is assigned a designated number that coincides with the maximum weight that the tire can support when it has been inflated.
- If your tire size is 255/60 R16/82S, the load rating/index would be 82 meaning the load in lbs would be 1,047lbs.
- A high tire load index number means the tire can hold a a greater load carrying capacity.
- If you purchase a tire with a lower load index than what is recommended for your vehicle, the tire will not be able to carry the weight of the vehicle.
- A Tire Speed Rating indicates the maximum speed capability or limit at which your tire was designed to perform.
- Although the speed rating indicated the max speed capability of the tire, this number does not imply that the tires can be driven on safely at it’s maximum speed, especially in harsh road conditions.
- If your tire size is 255/60 R16/82S, the “S” would indicate that the maximum speed capability for the tire would be 112mph.
~Courtesy of Sullivan Tire