It is generally believed that filling nitrogen in tyres offers benefits, such as no punctures, better fuel efficiency, higher performance and longer tyre life. So, for your car tyres, should you consider nitrogen over regular air, since the latter is already 78 percent nitrogen? Or are you overthinking basic air in a tyre? Let us find out.
What is the difference between nitrogen and regular air?
Nitrogen is a dry and inert gas, compared to regular air, which contains O2
Regular air is made of around 78 percent nitrogen and 21 percent oxygen, with the rest is made up of gases like carbon dioxide, argon, neon, helium, krypton, and xenon. In comparison, the nitrogen that is filled in tyres has a purity of almost 100 percent. As no oxygen molecule is present in nitrogen, it is a dry gas, which normal air is not.
Pros and cons of using nitrogen in tyres
Nitrogen, being dry, keeps the tyres at a more stable temperature than regular air
The O2 content in regular air, when compressed, allows moisture in the tyre. When the tyres warm, the moisture turns into vapour, leading to inconsistent tyre pressure. The dry nitrogen devoid of water vapours in any manner, on the other hand, remains at a more stable temperature. This is one of the reasons why tyres with regular air seem to blow out more at high temperatures than nitrogen-filled tyres.
The moisture in the air also leads to corrosion of the metal rims over time. Moreover, nitrogen is a larger and slightly less permeable molecule than oxygen. Hence, nitrogen tends to leak out slower than regular air.
Nitrogen comes at a price and is not as easily available as regular air
The charge of filling regular air is negligible, or even zero if you do it at fuel pumps. Nitrogen, however, is still chargeable at fuel stations and all tyre service workshops. Depending on your area, a top-up of all four tyres of your car can cost you between Rs 150 and Rs 200.
The availability of nitrogen filling stations, especially in underdeveloped areas and new expressways, is uncertain. In case of a tyre puncture or air loss in such areas, you may need to refill the tyres with regular air. While mixing regular air with the inert nitrogen gas in tyres does not have an immediate impact, in the long run, the water content in the regular air can convert into vapour at high temperatures, dissolving with the nitrogen. This can lead to unpredictable tyre pressure under both hot and cold tyre conditions, ultimately defeating the purpose of filling tyres with nitrogen.
Should you use nitrogen instead of regular air for tyres?
Nitrogen surely has its benefits, but it is not a substitute for poor tyre maintenance
If you want to do long highway runs, filling tyres with nitrogen could be one less worry on the trip, as it could mean fewer fluctuations in tyre temperatures, thus maintaining a more stable tyre pressure. Also, if you are planning high-speed runs, especially on tracks, nitrogen is recommended as it maintains an optimal tyre temperature, resulting in lower chances of a tyre burst. This is also the reason why motorsports and aerospace primarily use nitrogen in tyres.
For regular drives, however, it is recommended to just use regular air. Check tyre pressures regularly to maintain good tyre health, which would also save costs in the long run. Common beliefs of nitrogen contributing to no punctures, better fuel efficiency, zero tyre heating, and dramatically longer tyre life are untrue. Tyre maintenance, which includes practices such as regular pressure monitoring, proper wheel alignment, tyre rotation at regular intervals, and cautious driving, is a more important factor for tyre health than the type of air.
Uday Singh
Saptarshi Mondal
Viraaj Bhatnagar
Rivan RS 
