Should you fill your tyres with nitrogen?
If you’ve ever been offered the option of nitrogen inflation when buying new tyres, you might have wondered if it’s worth the extra spend. After all, the air we breathe is already 78 per cent nitrogen, 21 per cent oxygen and a sprinkling of other gases. And for decades, compressed air has done the job just fine – it’s free, it’s convenient, and it’s available at pretty much every service station.
So why the push for nitrogen?
Like all gases, regular air expands and contracts with temperature. For every 6°C rise in ambient temperature, tyre pressure can increase by around 1 PSI. Nitrogen, by comparison, is more stable. Strip out the oxygen and moisture from regular air and you’re left with a dry, inert gas that doesn’t fluctuate as much with heat.
That’s why nitrogen inflation has long been the norm in racing cars, aircraft, trucks and other heavy-duty applications. But does it make sense for the car you drive every day?
Why put nitrogen in your tyres?
Nitrogen inflation comes with a laundry list of claimed benefits. Advocates say it can improve safety, extend tyre life, reduce fuel consumption and even sharpen your car’s handling. Here’s how those claims stack up:
- More stable pressures: Nitrogen molecules are larger than oxygen molecules, so they leak out of tyres more slowly – three to four times slower, in fact. That means your pressures should remain more consistent for longer.
- Fuel economy gains: Under-inflated tyres increase rolling resistance, which forces your engine/battery to work harder. Keeping tyres at their correct pressure (whether by nitrogen or air) will help cut fuel use.
- Grip and safety: A correctly inflated tyre delivers the best possible contact patch with the road. Nitrogen can help keep pressures in the sweet spot for longer, and because it dissipates heat better than air, it reduces the risk of heat-related blowouts – especially on long trips or in hot conditions.
- Longer tyre life: Tyres that hold the right pressure wear more evenly. Nitrogen also eliminates the oxygen that can cause internal oxidation and rim corrosion, so in theory, you won't need to replace your tyres so soon.
- Less pressure-check hassle: With nitrogen leaking more slowly, you’ll spend less time at the service-station air pump.
How do I know if my tyres are filled with nitrogen?
Look for coloured valve caps which signal to service staff that nitrogen has been used.
Where can I get nitrogen, and how much does it cost?
This is where things get tricky. Unlike air, which is free and everywhere, nitrogen is harder to find. Tyre retailers are the most common places offering it, and it doesn’t come cheap: expect to pay around $9.50 per tyre, or nearly $40 for a small hatchback.
Is it worth it?
Here’s the bottom line: yes, nitrogen inflation can help maintain tyre pressures for longer, and yes, that has benefits. But for the average driver, those advantages are small – and they pale in comparison to the much bigger gains you’ll see simply by checking your air-filled tyres more regularly. Add in the cost and inconvenience of finding nitrogen, and for most drivers, sticking with air is the smarter choice.
