Our last HOW TO covered changing a tyre and it mentioned that you should regularly check your tyre pressure. So, how and when do you do that?

If you haven’t checked your tyres in over a month, then you might just be wasting fuel, and risking your safety.

Correct tyre pressure is important for three main reasons.

1. First, badly inflated tyres make it harder to handle your car on the road, impairing your ability to steer, corner, accelerate and brake.

2. Second, over and under-inflation wear your tyres down faster, as the wrong parts of the rubber make contact with the road.

3. And lastly, incorrect tyre pressure increases rolling resistance, burning more fuel and sending your fuel economy out the window.

Tyre pressure influences many important characteristics of vehicle performance, such as driving comfort, directional stability, cornering and braking grip, plus general handling behaviour, says the Automobile Association of New Zealand (AA).

Tyres lose air pressure naturally at a rate of around 1-2 psi (pounds per square inch) per month, so it’s important to monitor tyre pressures regularly to ensure optimal performance.

The psi or kPa (kilopascals) is based on your vehicle’s total weight and size, towing weight capability, and recommended tyre size. These pressures are set to keep you safe and comfortable on the road so it’s important to follow them, says the AA.

The ideal time to check your tyres are when they are cold, plus if you are planning on towing or have a heavy load then the tyre placards will outline slightly higher pressures.

Here are the steps by Bridgestone NZ on how to check your tyre pressure:

1. Before you can start checking your tyres, you’ll need to know what pressure is ideal. To do this, you’ll need to find the tyre pressure recommended by the manufacturer of your car. You can usually find this information on the driver’s side door frame, inside the fuel door, in the glove box, or in your car’s manual.

If you can’t find the recommended pressure, you should consult your vehicle dealer, manufacturer, or a qualified tyre professional.

2. Many petrol stations now have automatic tyre inflation. Simply set the desired pressure in kPa or PSI, then attach the lead to the valve of each of your rims. Attach the lead firmly to the valve, the machine will do the rest. If an automatic machine is not available, pressure will need to be added or removed then checked with a tyre pressure gauge.

3. Remove the valve cap from your tyre. Attach the air compressor hose to the valve stem. You can see in the picture below where you’ll need to attach the hose. Make sure you push on the hose so that air can’t escape while the tyre is filling.Press on the lever to fill your tyre. If you’re using an automatic tyre compressor, simply hold down the lever until you hear a beep. When the beep sounds, your tyres are at the set pressure.

If you’re using a manual air compressor, you will need to press the lever and let air into your tyre in short bursts, checking tyre pressure regularly and repeating as needed. Be aware that petrol station compressors can be inaccurate and may require you to double check the pressure with your own gauge to make sure the pressure is perfect.

4. If you find your tyre is overinflated, release some air by turning the valve cap around and then pushing on the valve core, or with your fingernail. If you find your tyre is underinflated, reattach the hose and refill your tyres, slightly increasing the desired kPA. Then, check the pressure is correct once you have finished.