Correct Tyre Pressure for UAE Heat: Cold vs Hot Readings

Where to find the right pressure

The correct pressure is set by the vehicle manufacturer for your car and tyre size. Michelin points drivers to three places: a sticker on the driver's door frame, the inside of the fuel filler flap, or the vehicle handbook. The figure may be shown in bar, psi or kPa; 1 bar is about 14.5 psi.

The front and rear tyres often need different pressures. Many labels also show two sets of figures: a normal pressure and a higher one for when the car is fully loaded with passengers and luggage. Some labels list several tyre sizes, so find the line that matches the size on your tyres.

Further reading: Michelin Middle East: what tyre pressure for my car?

Why the sidewall number is not your pressure

Every tyre has a maximum pressure moulded into the sidewall, often in small print near the rim. That is the highest pressure the tyre structure is designed to hold, not the pressure your car should run. Inflating to it makes the tyre too hard: the contact patch shrinks, grip and braking suffer, the centre of the tread wears faster, and the ride becomes harsh.

This is one of the most common mistakes at petrol station air machines. If you are unsure, use the vehicle label. Our guide to reading your tyre markings shows what the other sidewall numbers mean.

Cold pressure vs hot pressure

The recommended figure is a cold pressure: measured when the car has been parked for a few hours, or has been driven no more than a short distance. As you drive, the air inside the tyre heats up and the pressure rises. In UAE summer conditions the rise can be noticeable, and a reading taken after a motorway drive will be well above the label figure.

That rise is normal and is allowed for in the label figure. The mistake is to let air out of a hot tyre to bring it down to the label number. When the tyre cools, it will be under-inflated. Under-inflated tyres flex more, run hotter and wear the shoulders faster, and Michelin notes that driving on them damages the tyre structure and can lead to bursting.

• Best time to check: early morning, before driving.
• If you must check after driving, add air only if the reading is below the label figure, then recheck when cold.
• If the car has been parked in direct sun, the tyre on the sunny side may read higher than the one in shade.

Further reading: Michelin Middle East: what tyre pressure for my car?

How often to check

Tyres lose air slowly even when nothing is wrong. Michelin gives a typical natural loss of around 0.07 bar per month. Check pressures at least every two weeks in summer, and always before a long drive or before loading the car for a trip. Include the spare tyre if your car has one.

Use a reliable gauge. Petrol station gauges vary in accuracy, so a small digital or dial gauge kept in the car is a worthwhile purchase. If one tyre keeps needing air, it may have a slow puncture or a leaking valve; have it checked rather than topping it up every week. See puncture repair for what can be fixed.

Common pressure mistakes

Most pressure problems we see come from a handful of habits. Michelin notes that over-inflation causes faster wear in the centre of the tread and under-inflation causes faster wear on the shoulders, so the wear pattern often tells you which mistake has been made:

• Using the same pressure front and rear when the label gives different figures.
• Copying a figure from a different car or from a friend's advice instead of the label.
• Using the sidewall maximum as the target.
• Mixing up bar and psi on an air machine; 2.3 bar is about 33 psi, not 23.
• Forgetting to raise pressures for a full load, then forgetting to lower them afterwards.
• Ignoring a tyre that needs topping up more often than the others.

Further reading: Michelin Middle East: what tyre pressure for my car?

TPMS: helpful, but not a replacement for checks

Many modern cars have a tyre pressure monitoring system that warns when a tyre is significantly under-inflated. It is a useful safety net, but the warning usually comes only after pressure has dropped well below the correct level. Michelin advises not waiting for the warning before checking pressures.

If the TPMS light stays on after you have set the pressures correctly, a sensor battery may be failing, a sensor may be damaged, or the system may need to be reset after a tyre change. A TPMS sensor service can diagnose and replace faulty sensors.

Further reading: Michelin Middle East: TPMS tyre pressure monitoring system

Loaded cars and desert driving

If you are carrying a full load of passengers and luggage or towing, use the loaded pressure on the vehicle label. Running a heavily loaded car at the normal pressure is one of the conditions UAE police link to summer blowouts.

Desert driving is the one situation where drivers deliberately lower pressure, to give the tyre a longer footprint on soft sand. That is only safe at low speed on sand, and the tyres must be reinflated to the road pressure before returning to tarmac. Our all-terrain tyre guide covers this in more detail.

Nitrogen, new tyres and getting it checked

Some shops offer nitrogen filling. Nitrogen may lose pressure slightly more slowly than air, but it does not remove the need for regular checks or change the correct pressure. Ordinary air at the right pressure is fine for road cars.

When new tyres are fitted, the fitter should set the pressures to the vehicle label. 800 Motor fitters do this as part of every fitting at home, at the office or at a partner centre. If your tyres show uneven wear from running at the wrong pressure, it may be time for tyre replacement. Premium tyres such as Michelin are designed to work at the pressures the car maker specifies, like any other brand, so the label figure still applies.

Further reading: Continental: tyre pressure