What should my tyre pressure be and how often should I check it?

Tyres will typically lose around one to two PSI (pounds per square inch) a month, but the experts recommend car owners check their tyre pressure at least every fortnight to ensure there isn’t a slow leak or abnormal loss of pressure.

At the same time, you should also visually inspect the tyres by looking at the sidewall to ensure there are no cracks or gouges, and looking at the face of the tread to check there is nothing piercing the tyre.

If you've never used a tyre pressure gauge at a service station before, ask someone experienced to show you the ropes.

It's not that hard. Just unscrew the valve cap, fit the hose nozzle from the gauge to the valve and ensure the two make an airtight seal.

A conventional tyre pressure gauge will display the pressure immediately. If the pressure is too low, hold down the stubby lever fully on the hand-held gauge to pump more air and raise the pressure.

In the event the pressure is too high, press the lever down just enough to relieve air pressure.

Tyre pressure information is published in the owner's manual for your car. Look it up in the index at the rear of the manual.

If the manual is missing, left at home or buried deep within the recesses of your infotainment system in digital form, a tyre placard fitted to the car should provide easy access to all the information you need.

This placard is usually fitted to the car's frame, on the B-pillar, inside the driver's door.

The pressures recommended by the vehicle manufacturer are specifically for checking when cold. In other words, drive the car to the nearest service station to check the pressures; don't check them after the car has been on the road for an hour at the height of summer.

The pressures are measured in units of PSI (pounds per square inch), kPa (kilopascals) or bar. A common recommended tyre pressure is 30PSI, which converts to 207kPa or 2.07bar.

As a quick and dirty rule, multiply PSI by seven for kPa and divide kPa by 100 for bar. In practice, most gauges at service stations will display the pressure in at least two of these units of measurement.

Higher pressures (40PSI and higher) should be reserved for high-speed driving (at the racetrack, typically). The ride on the road will be hard and uncomfortable, and a vehicle with pressures set so high might exhibit premature signs of uneven tyre wear, leading to earlier replacement.

Most of the wear evident with over-inflated tyres will be at the centre of the contact patch.

Softer pressures (30PSI and below) will improve the ride, but detract from handling and roadholding – with the exception of off-road driving. Steering will be noticeably heavier in older cars without power steering.

Under-inflation will also result in premature wear, but around the edges of the contact patch instead – near each of the sidewalls.

Around 30 to 35PSI is a sweet spot for most drivers, but be aware that cars like old air-cooled VW Beetles demanded higher pressures at the rear, with all the weight from the engine located behind the rear axle.

It's always a good idea to learn what the tyre pressures for your car should be, even if it's regularly serviced by professionals [Ed: consult your owner’s manual or tyre placard for more information].

If an off-road vehicle becomes bogged, it's common to lower the air pressures to around 15PSI for significantly improved traction. But as soon as the vehicle is unbogged the pressure should be returned to the recommended setting.

Let the air pressure drop too low and the tyres will wear faster, they'll build up more heat and roadholding will be reduced. Really low pressures could result in the tyre rolling off the rim mid-corner.

Incorrect inflation – either too high or too low – could lead to a puncture or other tyre failure.

You can check for the correct tyre pressure at home, if you happen to have a portable air compressor in the garage. This works on the same principle as the pressure gauge and compressor at the service station.

Although the experts recommend a visual check for condition (such signs of age as cracks in the sidewalls), don't rely on visual checks alone to determine whether the tyre pressure is adequate.

A tyre could lose 10PSI or more without that lower pressure being obvious to the naked eye.

In addition, car owners should take care that the tyres are not worn.

Be conscious of how much tread is on your tyres, checking tread depth at least every month.

Paying more attention to your tyres will pay dividends. You will save money by getting longer life out of them before they need replacing. The car will be safer when braking, accelerating and cornering.

Get the pressures spot on and the ride comfort will be improved and road noise reduced also.

What's hard about checking tyres? Getting off your bum to do it.

Don't worry about checking if you're late for a doctor's appointment or a job interview. Wait for a moment when there's no must-see TV on the box and you're bored.

That's the perfect time to drive to the local servo and check the tyres. Your car will thank you.