Is Inflating tyres with nitrogen worth it

Posted on February 18th, 2015 by Rob Marshall

 NitrogenAccording to Tyre Bay Direct, the British motorist is not very adept at checking his (or her) vehicle’s tyre pressures. The firm has a point. While the company says that 86% of cars involved in all UK collisions possessed incorrect tyre pressures, (even though it gives no clarification about when the data was collected and for how long), the statistic is unsurprising and depressing. Under-inflated tyres not only affect vehicle grip, ride and handling characteristics but they also reduce tyre life and increase fuel consumption.

According to its recent press release, there is a solution. Nitrogen inflation will negate the gradual pressure loss, which can require air top-ups every fortnight, or so. The main rationale used is that nitrogen gas is more resistant to ‘leaking’ out of the tyre, the rubber of which is a permeable membrane, compared with impure compressed air. Further ‘evidence’ cites extreme conditions, where nitrogen’s advantages are both useful and proven.

However, an aircraft tyre that has to tolerate -40 degrees Celsius in mid-flight, or a Grand Prix racing car that scorches to over 200mph, holds little relevance for the average domestic runabout. Indeed, while nitrogen is less prone to leaking from the tyre’s structure, owing to its larger molecular size, natural pressure losses still occur. Several premium tyre manufacturers that we consulted also agreed that the advantages of filling-up with ‘supersonic’ nitrogen are largely irrelevant for the average motorist. Furthermore, nitrogen will neither reduce pressure loss significantly in a slow-puncture situation, nor when the rubber tyre is mounted to a corroded wheel rim lip.

Worryingly, ‘filling up’ with nitrogen might lead a driver to believe that periodic checks are no longer necessary. Yet, those future top-ups would have to be performed, possibly inconveniently, at a suitably-equipped tyre fitting station, to maintain the slimmest of advantages.

For me, the answer is simple. Instead of filling up with nitrogen, save the notional £5 cost and buy a tyre pressure gauge, so that you can check your pressures on a regular basis at home. Be wary that pressure losses have been attributed recently to pothole damage, where air has escaped from resultant cracks in aluminium wheel rims. Inspecting them for damage is also worthwhile.

So, unless you are Lewis Hamilton, or a top-flight airline pilot, forget the gas and just check the air as a matter of course.