See also:

Tire ply composition and material used
Describes the number of plies or the number of layers of rubber-coated fabric in the tire tread and sidewall. These are made of steel, nylon, polyester and other materials. ...

DOT (Department of Transportation)
DOT marked tires fulfill the requirements of the United States Department of Transportation. ...

PSI (pounds per square inch)
A standard unit of measure for tire pressure. ...