Inaccurate pressure can cause poor mileage, uneven tyre wear, or a tyre blow-out. To prevent these events from happening, it is important to proper maintenance of your car tyres pressure. Check your car tyres pressure at least once a month or before long trips to ensure that you're getting the most out of your tyres - and that your tyres are being treated well.
Checking Air Pressure in Tyres
Step 1 Make sure the tyres are cold.
This means that the vehicle has been parked for at least three hours, or driven less than 1.6 km. Checking air pressure in cold tyres ensures that the air hasn't expanded from heat, giving you a more accurate reading.
Step 2 Discover the proper air pressure on the inside of the driver's side door or look in the owner’s manual for the recommended cold tyre inflation pressure.
This number is the lowest PSI (pounds per square inch) one would inflate the tyres to and is suggested by the car's manufacturer. Read below for reasons inflation may be placed higher.
- For most Sedans, Mini-Vans, and even Mini Pickups, manufacturers generally recommend a PSI in the range of 27 to 32, but can reach all the way up to 40.
- For larger vehicles that need to carry a larger burden, such as Trucks and Sports Utility Vehicles (SUVs), the PSI is generally 4 to 8 PSI greater than it would be in smaller cars, perhaps around 45.
- Also note that the front and back tyres may need different pressures, according to the manufacturer.
Step 3 Remove the tyre valve cap from the valve stem on the tyre.
The valve stem is a black pencil-sized extension near the hubcap, about 1" (2-3 cm) long.
Step 4 Press the tyre pressure gauge against the open valve stem and record the reading given.
If there is a hissing sound, the tyre gauge is not tight or even enough for an accurate reading. The angle of the tyre gauge may need to be adjusted.
- If you are using a digital tyre pressure gauge, you may or may not need to press a button in order for the gauge to read the air pressure. If you are using a traditional tyre gauge, the metered stick should give you a reading automatically.
Step 5 Note that if the reading is the same as the recommended cold tyre inflation pressure, you are done after checking all other tyres for the same pressure.
If the pressure is too low, you can add air. If the pressure is too high, you can let air out of the tyre. Make sure you put in the correct amount.
Step 6 Replace tyre valve cap.
The cap does not hold air in, but it keeps dirt and moisture away from the valve mechanism in the valve stem, which does hold air in.