Tire Designations

In accordance with international standards, the tire size is given in millimeters or, as in our case, in a mix of millimeters and inches. The designations 195/65 R 15 91 T or 205/65 R 15 91 V mean the following:

195 or 205: tire width in the unloaded state in mm.

What information is contained on the markings on the tire sidewall, as shown in the illustration:
Maximum load
Inflation pressure
Ply rating
Sidewall
Tread
DOT* check
* DOT – Department of Transportation
Manufacturer's code
Tire size code
Tire type code (optional, set by the manufacturer for internal use)
Week of manufacture
Year
Radial tire
Tubeless
Nominal width
Aspect ratio
Radial tires
Rim diameter
Load index or load rating
Speed rating
ECE* conformity marking (approval marking with country code, e.g. 3 – Italy)
* ECE – Economic Commission for Europe
Approval number
65: ratio of tire height to width = 65:100. Standard radial tires, which are no longer used in this form for Audi 80, had a height/width ratio of 80:100.

R: designation of the tire construction as radial.

15: inside diameter of the tire in inches (").

91: load capacity
Q: maximum permissible speed up to 160 km/h – speed rating for standard M+S tires (all-season tires – literally: for mud and snow).

S: up to 180 km/h
T: up to 190 km/h – including high-speed all-season (M+S) tires.

H: up to 210 km/h
V: up to 240 km/h
Z: over 240 km/h