A. Tyre Width
Width of the tyre measured in millimetres (sidewall to sidewall).
B. Profile Ratio
This is the ratio of the height of the tyre sidewall, expressed as a percentage of the width: “55” means that the sidewall height is equal to 55% of the tyre’s width.
The “R” refers to the construction of the tyre. It stands for radial, which means that the body is made with radial ply cords. A “B” would indicate that the tyre is of bias construction, meaning that the body ply cords run diagonally across the tyre alternating with the ply layers so they reinforce and complement one another.
C. Wheel Diameter
The diameter of the wheel rim in inches.
D. Load Index
Indicates the maximum load that a tyre can support when properly inflated. You’ll also find it in pounds and kilograms elsewhere on the tyre’s sidewall.
E. Speed Rating
Shows the maximum service speed for a tyre. “V” means that the tyre has a maximum service speed of up to 149 mph (239 kph). Please note: These ratings relate only to tyre speed capability, and are not an invitation to exceed legal speed limits.
F. DOT Safety Code
Means the tyre is compliant with all applicable safety standards established by the U.S. Department of Transportation (DOT). Adjacent to this is a tyre identification or serial number: a combination of numbers and letters with up to 12 digits.