Nitrogen in your tyres: what it does and what it does not

What nitrogen filling is

Normal compressed air is already about 78% nitrogen. The rest is mostly oxygen, plus some water vapour. Nitrogen filling uses a generator or cylinder to supply gas that is mostly nitrogen, with far less oxygen and moisture. Our vans carry a nitrogen supply alongside the compressor, so we can fill on the spot during any visit.

Tyres filled with nitrogen are usually marked with green valve caps, which helps the next person who inflates them know what is inside.

The real benefits

• Slower pressure loss. Nitrogen molecules pass through tyre rubber a little more slowly than oxygen, so a nitrogen-filled tyre loses pressure more gradually. That means less time running under-inflated between checks.
• Less moisture inside the tyre. Dry gas means less water vapour, which can help reduce corrosion of steel wheels and TPMS sensor valves over time.
• Slightly steadier pressure. With less moisture inside, pressure changes a little less unpredictably as the tyre heats up and cools down.

What nitrogen does not do

This is where sales talk often goes too far. Nitrogen behaves almost exactly like air when it heats up. A tyre filled with nitrogen in a Dubai car park at 7am will still rise noticeably by mid-afternoon on the Al Khail Road, just as an air-filled tyre would. Nitrogen also does not:

• Seal punctures or slow a leak from a nail, valve or damaged bead.
• Make a tyre immune to blowouts. Under-inflation, overloading and age cause blowouts, and nitrogen does not change those.
• Deliver large fuel savings on its own. Any saving comes from keeping pressure at the correct level, which regular checks with air also achieve.
• Remove the need for pressure checks. Every two weeks, cold, is still the rule.

Nitrogen versus air at a glance

Who it makes sense for

Nitrogen is most useful for drivers who do not check their pressures as often as they should, because it buys a little more margin between checks. It is also a reasonable choice for cars that sit for long periods, such as a weekend 4x4 or a car parked while the owner travels over the summer, since the tyres hold pressure a little better while the car is idle. For a daily driver whose owner checks pressures every two weeks, the difference is small.

When we fit new tyres, we fill with nitrogen at no charge, so the question only really comes up for existing tyres. At AED 10 per tyre, it is cheap enough to try if you are curious.

Nitrogen and UAE summers

Summer is when nitrogen is sold hardest, often with the promise that it keeps tyres cool. It does not. Pressure in any tyre rises by roughly 1 psi for every 5 °C, whatever gas is inside, and road surfaces in July and August get far hotter than the air. The practical advice is the same for both: set pressure cold, early in the morning, to the door-placard value, and never let air out of a hot tyre because the reading looks high. Releasing pressure from a hot tyre leaves it under-inflated once it cools, and under-inflation is what builds dangerous heat at highway speed.

Topping up and mixing

Mixing nitrogen and air is completely safe. If a nitrogen-filled tyre is low and the only option is the air line at a petrol station, use it: the right pressure matters far more than the gas. You will lose some of the nitrogen benefit, and it can be restored at your next visit. For correct cold pressures by car type, including summer and desert settings, use our tyre pressure guide, or book a tyre pressure check at your location.

If a nitrogen-filled tyre keeps dropping, the gas is not the issue. A slow leak needs finding, usually a nail, a corroded valve or a failing TPMS seal. Our puncture repair service covers that from AED 80.