The Meaning of the Tire Size Code
The tire size code consists of a string of letters and numbers as follows:
- An optional letter (or letters) indicating the intended use or vehicle class for the tire:
- P - Passenger
- LT - Light Truck
- ST - Special Trailer
- T - Temporary
- 3 digit number - The width of the tire in millimeters, from sidewall edge to sidewall edge.
- / - Slash Character
- 2 digit number - The ratio of the sidewall height to the total width of the tire as a percentage. If this is missing, it is assumed to be 82%. If the number is larger than 200, then this is the diameter of the entire tire in millimeters.
- Construction of the fabric of the tire
- B - bias belt
- D - diagnol
- R - radial
- 2 digit number - Diameter in inches of the rim that this tire is designed to fit.
The tire might be labelled:
- 'P' these tires are for a passenger vehicle.
- 195 – the width of the tire is 195 mm at the widest point.
- 55 – indicates that the height of the side-wall of the tire is 55% of the width - 107 mm.
- R – this is a radial tire.
- 16 – this tire fits 16 inch diameter wheels.