This tire size means:
* P indicates a passenger car tire.
* 215 is the tire width in millimeters.
* 75 is the aspect ratio, which is the tire height as a percentage of the width.
* R indicates a radial tire.
* 15 is the wheel diameter in inches.
* 97 is the load index, which indicates the maximum load that the tire can carry.
* S indicates the speed rating, which indicates the maximum speed at which the tire can be safely used.
