And just an FYI:
Radial tires are generally built with 2 radial plies (bead to bead which includes the sidewalls) and 2 additional steel plies under the tread. Sometimes there are nylon (or generic name polyamide) cap plies ( 1 or 2).
This is true for passenger car tires, light truck tires and ST tires.
Variations: Small Passenger car tires may need only a single ply for strength purposes.
Large truck tires (over the road size) are frequently made with a single steel body ply. These tires usually have additional plies in the belt area that function like cap plies.
Some off road LT tires may use 3 sidewall (body) plies. This is more for damage resistance than strength.
US regulations require the construction to be written on the sidewall of all street tires. It will appear in the form:
Sidewall: 2 plies polyester
Tread: 2 plies polyester, 2 plies steel, 1 ply nylon.
(or what ever the construction is)