If you’ve ever experienced a flat tire, you may have noticed that it isn’t always totally empty of air. What has happened is the compressed air inside has leaked out so much that the weight of the car cannot be supported anymore. Tire pressure is the atmospheric pressure inside the tire, usually rated in pounds per square inch (psi) or kilopascals (kPa).
What is the purpose of tire pressure?
The air inside your tires serves many purposes:
It provides cushioning for a comfortable ride. An over-inflated tire rides much harder than one that is properly inflated, while under-inflated tires can cause the sensation of floating.
It enables easier rolling resistance and less road friction. The result is better fuel economy and less heat generated by the tires.
It prevents unnecessary or uneven tire wear. Excessive friction from under-inflated tires causes heat, which accelerates tread wear and wears out the outer edges of the tires. Over-inflated tires wear the center part of your tire, and can affect the steering feel of the vehicle.
How to determine the correct pressure for your tires
The optimal tire pressure for your vehicle is written on a placard located in the driver’s door jamb in nearly all cases. Some placards are in the glove box or on the edge of the door itself. The tire pressure rating on the placard should be adhered to.
Note: There is a maximum tire pressure embossed on the tire itself which should NOT be used. It is there to indicate the maximum safe pressure of the tire itself, but can and will cause undesirable driving feel and excessive tire wear.