The Right Tyre Pressure: How to Check It and Why It Matters

Published 2026-05-05 · Park Royal Tyre & Alignment Centre

Tyre pressure is one of those things most drivers never think about until something goes wrong. Yet it quietly shapes how your car stops, steers, grips in the wet and how much you spend on fuel. Run your tyres too soft or too hard and you wear them out faster, lengthen your braking distances and make the steering feel vague. The good news? Checking and correcting pressure takes a couple of minutes, costs nothing at home and needs no special skill. This guide walks you through where to find the right figures for your car, how to check them properly, and why getting it right matters more than you might expect.

Where do you find the recommended tyre pressure?

Your correct tyre pressures come straight from the vehicle manufacturer, and they're printed in three easy-to-find places. Look first at the driver's door sill, the painted edge you see when the door is open. Many cars carry a small label there listing front and rear pressures, often with separate figures for a light or fully loaded car.

If there's nothing on the door, check inside the fuel filler flap, where a similar sticker is sometimes fitted. Failing both, your owner's handbook will have a dedicated section, usually with a clear table. Whatever you do, don't use the big number moulded into the tyre sidewall. That figure is the tyre's maximum safe pressure, not the pressure your particular car is designed to run.

Why should you check tyre pressure when the tyres are cold?

Air expands as it warms, so a tyre that's been driven on reads higher than the same tyre standing cold. Manufacturer pressures are quoted "cold", meaning the car has been parked for a few hours or driven no more than a mile or two at low speed. Check then and your reading will be honest.

Why does this catch people out? Roll onto a forecourt after a thirty-minute motorway run and the heat in the tyres can push the pressure up noticeably. Adjust to the recommended figure in that warm state and you'll actually be running under-inflated once everything cools down. If you can only check after a longer drive, it's better to top up at home first thing, when the tyres have had all night to settle.

How do you check and adjust tyre pressure?

Checking pressure is simple with either a forecourt machine or a decent home gauge and a small compressor. Unscrew the dust cap from the valve, press the gauge firmly and squarely onto the valve until the hissing stops, and read the figure. Compare it against the manufacturer's number, then add or release air until they match.

Work through all four tyres, and don't forget the spare if your car carries one, since a flat spare is no use in an emergency. Refit every dust cap afterwards to keep grit out of the valve. Forecourt gauges can drift out of calibration, so if a reading looks odd, try a different machine or get it confirmed properly. A quick professional check during any tyre visit removes the guesswork entirely.

What happens if your tyres are under or over-inflated?

Getting pressure wrong in either direction costs you grip, money and tyre life. An under-inflated tyre flexes too much in the sidewall, builds up heat, and wears heavily along both shoulders. It also rolls less efficiently, so the engine works harder and your fuel economy drops. In the worst case, that excess heat can lead to a sudden blowout at speed.

Over-inflation causes the opposite problem. A rock-hard tyre bulges in the middle, so only the central band of tread touches the road. That shrinks your contact patch, wears the centre prematurely and gives a harsher, bouncier ride with less grip, especially on wet or uneven surfaces. Both extremes also upset braking and handling. The car simply doesn't respond the way it should when you need it most, which is exactly why the manufacturer's figure exists.

Do you need different pressures for a heavy load?

Yes, and this is where that second column on the door label earns its place. Many cars list a standard pressure for everyday driving and a higher one for when the vehicle is fully laden, carrying several passengers, luggage or towing. The extra weight squashes the tyres more, so raising the pressure keeps them properly supported.

Think about a fully packed car heading off on holiday, or a van loaded for a job. Sticking with the light-load pressure under that weight effectively under-inflates the tyres, with all the wear and heat problems that brings. Set the higher figure before you set off, then drop back to the normal pressure once you've unloaded. Your handbook spells out exactly which figure applies to which situation, so there's no need to guess.

How often should you check your tyre pressure?

A monthly check is the sensible habit to build, plus a look before any long journey. Tyres lose air naturally over time, even with no puncture, so a tyre that was spot-on last month may have crept down since. A regular routine catches that slow loss before it affects your safety or your fuel bills.

Pay extra attention as the seasons turn, because falling temperatures lower pressure too, which is why tyres often read low on cold winter mornings. If one tyre repeatedly drops faster than the rest, treat it as a warning sign of a slow puncture or a leaking valve rather than just topping it up again. That's the point to have it inspected, before a small leak turns into a roadside stop.

Frequently asked questions

Can I use the pressure number printed on the tyre?

No. The figure moulded into the sidewall is the tyre's maximum permitted pressure, not the right pressure for your car. Always use the manufacturer's recommended figures from the door sill, fuel flap or handbook, as these are matched to your specific vehicle and its weight.

Is it safe to drive with slightly low tyre pressure?

A little low won't strand you, but it's not something to leave. Even mild under-inflation increases wear, raises fuel use and lengthens braking. Top up to the correct figure as soon as you can, and if a tyre keeps losing air, have it checked for a slow puncture or valve fault.

Does cold weather really change my tyre pressure?

Yes. Air contracts as it cools, so pressures naturally fall in colder weather and rise as tyres warm up. This is why tyres often read low on a frosty morning. Always set pressures cold, and check more often through winter so a genuine leak isn't mistaken for normal temperature change.

Should I check the pressure in my spare tyre?

Definitely. A spare is useless if it's flat when you need it most. Include it in your monthly check where the car carries one. Space-saver spares often require a higher pressure than the road tyres, so check the figure marked on the spare itself or in your handbook.

Not sure your tyres are running at the right pressure? Don't leave it to guesswork. Pop into Park Royal Tyre & Alignment Centre in Park Royal, London NW10 7TR for a quick, honest pressure and condition check, or to sort a slow puncture with our tyre fitting and repair service. You can browse replacements on our tyres page too. Call us on 020 3886 2355, message us on WhatsApp at 07476 586 589, or get in touch here to book a convenient time.