The tires that came on your vehicle have a number of markings. Those you should be aware of are described below.
Here is an example of what each marking means:
P215/50R17 94V
P: tire type (passenger vehicle)
215: tire width in millimeters
50: aspect ratio (tire section height as a percentage of its width)
R: tire construction code (radial)
17: rim diameter in inches
94: load index (code indicating maximum load tire can carry)
V: speed symbol (code indicating maximum speed rating)
The tire identification number (TIN) is a group of numbers and letters that look like the example shown. TIN is located on the sidewall of the tire.
Cold Tire Pressure - The tire air pressure when the vehicle has been parked for at least three hours or driven less than 1 mile (1.6 km).
Load Rating - The maximum load that a tire is rated to carry for a given inflation pressure.
Maximum Inflation Pressure - The maximum tire air pressure that the tire can hold.
Maximum Load Rating - The load rating for a tire at the maximum permissible inflation pressure for that tire.
Recommended Inflation Pressure - The cold tire inflation pressure recommended by the manufacturer.
Treadwear Indicators (TWI) - The projections within the principal grooves designed to give a visual indication of the degrees of wear of the tread.