When tires are inflated correctly, a vehicle is easier to control in an emergency and less likely to roll over in an accident. Proper tire pressure also makes cars up to three percent more fuel efficient, and properly inflated tires wear better and last longer.
Proper tire pressure is such a significant safety concern that since 2007, vehicles come equipped with tire pressure monitoring systems. These systems use a dashboard indicator light to let you know when tire pressure is incorrect.
These systems can be a lifesaver as far as notifying a driver about dangerous tire pressure, but it is still a good idea to know how to manually check tire pressure and add air if you are able to do so.
Why Tires Lose Pressure
Auto tires lose pressure
- When air temperatures change
- When the load in the vehicle increases or a trailer is pulled
- When the car is driven for long periods.
Tire pressure also goes down if there is a puncture in the tire or damage to the valve stem. Sometimes, small pebbles can lodge between the metal tire rim and the rubber, creating a small gap where air leaks out.
How to Check Tire Pressure
Even if your vehicle has a tire pressure monitoring system, having a tire pressure gauge is a good backup. Electronic monitoring systems do not always work accurately and may incorrectly indicate low pressure. Having a hand-held gauge lets you verify what the system is telling you. Also, if you add air to the tires yourself, you need a gauge to check the pressure after you have added the air.
Tire pressure gauges indicate the tire pressure using a stick, dial, or a digital readout display. Which type of readout is best is mostly a matter of personal preference. These devices are available at auto and hardware stores for about ten dollars.
Before you add air to your tires, you also need to know the correct inflation pressure. The best place to find this information is in the vehicle owner’s manual. Recommended tire pressure is also often printed on a small metal tag posted on the inside edge of the driver’s side door frame.
Check tire pressure when the car has not been driven for several hours. Remove the small screw cap covering the valve, push the gauge firmly onto the valve stem until the pressure goes up on gauge readout, then remove the gauge from the tire and read the pressure.
If the pressure is higher than it should be, use the small nub on the end of the pressure gauge to depress the tiny bar in the center of the valve to release air. If the pressure is lower than it should be, add air using an air compressor. Air for tires is usually available at gas stations for free to customers and at a small charge for non-customers.
When you check the tire pressure with a gauge, it is often necessary to take two or three readings to be sure the gauge is seating tightly on the valve stem and recording the correct pressure. After checking and adjusting the pressure in each tire, replace the valve caps on the valve stems.