Did you know that it’s possible to inflate tyres with nitrogen instead of air? An increasing number of tyre retailers and garages are offering this option, and it has become popular with driving enthusiasts. But what’s the real benefit of having nitrogen-filled tyres on your wheels? Isn’t it a technique specific to the race track? Read on to find out.
As we are fond of reminding our customers, we design and construct tyres to provide many miles of excellent service. However, the owner of the vehicle also has a responsibility to check on the tyres now and then. The most straightforward rule for long-term tyre care is to keep them at the proper tyre pressure.
The manufacturer of your car specifies the optimal tyre inflation pressure; these details are either in the vehicle handbook or inside the door on the driver’s side. We recommend checking your tyre inflation pressure at least once every two weeks (and especially before embarking on a long car journey).
So, where does nitrogen feature in the conversation? Well, the behaviour of any gas is such that it expands when heated and contracts when cooled, and nowhere is this more evident than with the gases inside a tyre.
The inflation pressure rises and falls according to changes in temperature; every 12 degrees Celsius (approx. 10 degrees Fahrenheit) results in a shift of 1 PSI (pound per square inch). For this reason, it’s better to check tyre pressure early in the morning before the heat of the sun (or heat generated by driving) causes the temperature to increase. Cold air pressure readings are going to be more accurate.
In this scenario, nitrogen-filled tyres are advantageous because nitrogen gas doesn’t support moisture or combustion. Compared with ambient air – which contains roughly 78 per cent nitrogen, 21 per cent oxygen, plus miscellaneous gases – pure nitrogen is an inert, non-flammable gas. Essentially, it’s dry air with the oxygen wholly removed.
Thanks to these inert properties, tyres inflated with nitrogen are beneficial for highly specialised service applications in demanding environments, such as aviation, mining or construction.
Dry nitrogen mitigates tyre pressure variations, so nitrogen-filled tyres are also used in professional racing, where even the smallest changes in pressure can impact ultra-high-performance vehicle handling at extreme speeds.
So, now we come to the big question: is nitrogen right for your tyres? The fact of the matter is that inflating tyres with nitrogen is not necessary for typical everyday use on a passenger car. It might even be considered a frivolous waste of money.
To be clear, inflating tyres with nitrogen is not harmful. Moreover, the PSI stays steady in the long term. (Tyres filled with regular air lose pressure through permeation a little more quickly.)
But for the most part, nitrogen makes absolutely no difference when it comes to a loss of pressure caused by tyre punctures, tyre bead leaks, valve leaks or other mechanical leaks. There’s no discernible benefit over air-filled tyres, and that includes performance factors such as rolling resistance, fuel economy and tyre aging.
To emphasise the point once more, check your tyre inflation pressure regularly. If the pressure is below the manufacturer recommendation, the tyre must be inflated again – either with air or, if you so choose, with nitrogen – to the proper inflation pressure. For your safety, you must not drive with tyres that are either under-inflated or over-inflated. This could create excessive strain and heat build-up and lead to catastrophic tyre failure, and the risk of serious injury or fatalities.
If in doubt, consult your vehicle handbook for the complete details of the maximum load-bearing recommendations. Also, consider investing in a Tyre Pressure Monitoring System for complete peace of mind.