What is PSI?
Open your car's glove compartment, pull out your owner's manual, and look up “tires." You should find details including front and rear “PSI" listings. PSI stands for pounds per square inch. This number is determined by your vehicle's manufacturer, and it's how you can tell if your tires are properly inflated.
PSI is based on your vehicle's:
Total weight and size.
Towing weight capability.
Recommended tire size.
It's important to note that you should always use the pressure recommended by your vehicle's manufacturer to ensure optimal vehicle performance. This means you need to ensure that your tires are appropriate for your vehicle, and that the PSI recommended for the tire matches what your vehicle's manufacturer recommends for your car.