The type and size of tires that are compatible with a car depends on the make and model of the vehicle. The best way to determine what size tires a car needs is to check the manufacturer's guide for the vehicle.
One can also determine the proper size of tires by reading the sidewall markings of the tires currently on the vehicle. The sidewall is the side of the tire facing outward. The tire size will be a string of numbers and letters. An example tire size is "185/60R14." A tire with this size is 185 mm wide, has an aspect ratio of 60 percent and has a diameter of 14 inches.