Every driver should know how to check tire pressure and how to inflate tires as these maintenance procedures are essential for the safe operation of your automobile. Checking tire pressure regularly can decrease tire wear, increase fuel economy, improve handling, and help prevent blow-outs.
The manufacturer's suggested tire pressures for your vehicle can be found in the owners manual and usually inside one of the door jams. The front and rear pressures are often the same, but sometimes different pressures are recommended for safe handling. The pressure listed on the tire itself is the maximum pressure the tire should be inflated to and not a recommended pressure. Always check the pressure when the tires are cold as driving will heat up the air inside them causing it to expand and artificially increasing readings.
Each wheel will have a valve stem used to fill it with air and check its pressure. Locate the stem and remove the cover (if present) by unscrewing it. Place your pressure gauge firmly over the stem for a couple of seconds to allow the pressure to stabilize and then check the reading. You may hear the sound of air leaking from around the gauge as you initially press it onto the valve. If you continue to hear air escaping your reading will not be correct - make sure that the valve and gauge are clean, and try again.
If the pressure is low you will need to add air with a pump. The pump should come with directions of its own, but the process if normally straightforward. Depending on the design usually it's simply a matter of holding the hose against the valve, screwing the end of the pump over the valve, or placing the end of the pump on to the valve and flipping a lever. You may need to turn on the power or pump manually. Be careful not to over-inflate the tire as this can cause the tire to explode. Allow the pump to run for a short period and then check the pressure, some pumps will inflate the tire much more rapidly than others.
If the pressure is high you will need to let some air out. This can be accomplished by pressing the middle part of the valve down with a small object. Often the back of the valve stem cap can be used for this purpose, otherwise a key should do the trick. Allow a small amount of air to escape and then check the pressure. Once the pressure is at the manufacturer's recommended values replace the valve stem cover and move on to the next tire.