How to Check Tyre Pressure the Right Way

A tyre can look perfectly fine and still be well underinflated. That is why knowing how to check tyre pressure properly is one of the simplest ways to improve safety, tyre life and fuel economy. It takes only a few minutes, but it needs to be done with the right pressure figure and when the tyres are cold.

For drivers around Wallsend and Newcastle, New South Wales, changing temperatures, busy commuting and weekend trips can all affect tyre pressure. A quick check before a longer drive is cheap insurance against uneven wear, poor handling and an avoidable roadside problem.

Find the correct tyre pressure first

Before reaching for a tyre gauge, find the recommended pressure for your specific vehicle. This is usually shown on a tyre placard inside the driver's door opening, behind the fuel flap or in the owner's manual. It will normally list pressures in kPa, and sometimes PSI, for normal loads and fully loaded driving.

Use the vehicle manufacturer's placard, not the number moulded into the tyre sidewall. The sidewall figure is the tyre's maximum pressure rating, not the pressure your car should run every day. Inflating tyres to that number can make the ride harsh and reduce the tyre's contact patch with the road.

If your vehicle has different tyre sizes front and rear, or you run a 4WD, pay close attention to the placard. Front and rear pressures may differ. There may also be a higher setting for carrying tools, towing, loading up the family or heading away with camping gear.

What you need to check tyre pressure

A basic tyre pressure gauge is all you need. Digital gauges are easy to read, while pencil-style and dial gauges also do the job when they are in good condition. The gauge at a servo air station can be useful, although having one in the glovebox or garage gives you more control over regular checks.

You will also need access to an air compressor. Most service stations have one, and many drivers keep a portable 12V compressor in the car. It is particularly handy for 4WD owners and anyone travelling beyond built-up areas.

Check the tyres when they are cold

Tyre pressure should be checked before you drive, or after the vehicle has been parked for at least three hours. Tyres heat up as they roll, and the air inside expands. A reading taken after driving can be several kPa higher than the true cold pressure.

If you need to check pressures at a servo after a short trip, it is better than not checking at all. Just understand that the reading may not be exact. Do not let air out of a warm tyre simply because it is above the cold-pressure recommendation. Check it again the following morning before driving.

Ambient temperature makes a difference too. Cold Newcastle mornings can lower tyre pressure, while a hot day can raise it. This is one reason monthly checks are worthwhile even if the tyres appear normal.

How to check tyre pressure step by step

Park on level ground, apply the handbrake and make sure the tyres are cold. Remove the small valve cap from the first tyre and keep it somewhere clean. The cap helps keep dirt and moisture out of the valve, so it is worth replacing if it has gone missing.

Press the tyre gauge firmly and squarely onto the valve stem. You may hear a brief hiss as it seals. Hold it in place until the gauge gives a stable reading, then compare that figure with the pressure on the vehicle placard.

If the tyre is low, add air in short bursts and recheck it. It is easy to put in too much air, especially with a powerful compressor. If you overinflate it, use the small pin inside the valve to release a little air, then test again.

Repeat the process on all four tyres, then check the spare if your vehicle has one. The spare is often forgotten until it is urgently needed, and it may require a higher pressure than the tyres on the ground. Check its specified pressure on the placard or in the manual.

When finished, screw the valve caps back on securely. They only need to be finger-tight.

How often should you check tyre pressure?

For most vehicles, once a month is a sensible routine. Also check before a long road trip, after carrying a heavy load, before towing, and whenever a tyre looks soft. If you strike a pothole, kerb or road debris, inspect the tyre and pressure as soon as it is safe to do so.

A vehicle fitted with a tyre pressure monitoring system can give useful warning of a significant pressure loss, but it does not replace manual checks. Some systems alert you only after a tyre is already considerably low, and they may not tell you whether all four tyres are set correctly for the load you are carrying.

Why the right pressure matters

Underinflated tyres flex more as they travel. That creates heat, increases rolling resistance and wears the outer edges of the tread faster. It can also make steering feel vague, reduce fuel economy and increase the risk of tyre damage on a long drive.

Overinflated tyres are not ideal either. They can produce a firmer, less comfortable ride and may wear more quickly through the centre of the tread. On uneven roads, an overinflated tyre can have less ability to absorb impacts.

Correct pressure helps the tyre do its job as designed. It supports predictable braking, steering and stability, particularly in wet weather or during an emergency manoeuvre. It also helps you get the most life from a set of tyres, which is better for the budget than replacing them early.

Adjusting pressures for loads, towing and 4WD use

The normal pressure listed on the placard suits ordinary day-to-day driving. If you are loading the boot with work gear, taking passengers away for the weekend or towing a trailer, check whether the placard specifies a higher pressure. A heavier load places more demand on the tyre and often needs more air to support it safely.

Do not guess the adjustment. Pressure requirements depend on the vehicle, tyre size, load rating and axle load. This is especially relevant for utes, SUVs and 4WDs, where tyre pressures can vary greatly between unladen commuting, towing and off-road conditions.

For sand, gravel or off-road driving, drivers sometimes reduce pressure to improve traction and ride comfort. That can be appropriate in the right conditions, but it needs to be done carefully and reinflated before returning to sealed roads. Driving at reduced pressures on bitumen can quickly overheat and damage a tyre.

Check for more than just low pressure

While you are down at tyre level, take a close look around each tyre. Look for nails, screws, cuts, cracking, bulges or rubbing damage on the sidewall. A bulge can indicate internal damage and needs prompt professional attention, even if the tyre is still holding air.

Have a look at the tread wear as well. Wear concentrated on both outer shoulders often points to low pressure, while excessive wear down the middle can suggest overinflation. Uneven wear on one edge, feathering or patchy wear may be linked to wheel alignment, suspension or steering issues rather than pressure alone.

If one tyre repeatedly loses pressure, do not keep topping it up and hoping for the best. It may have a puncture, leaking valve, damaged rim or another fault that needs repair. A qualified mechanic can inspect the tyre properly and advise whether it can be safely repaired or needs replacement.

A small check that prevents bigger costs

Checking pressures regularly gives you a better feel for your vehicle and helps catch issues before they become expensive. Keep a reliable gauge in the car, follow the placard rather than the tyre sidewall, and make cold-pressure checks part of your monthly routine.

If you are unsure about tyre wear, a slow leak or the right pressures for your load, Scott Forbes Automotive can inspect the tyres and the related steering or suspension components. A few minutes of attention now can make the next commute, school run or highway trip safer and less costly.