Filling Your Tyres With Nitrogen Is A Waste Of Money
You might have been asked by your local service centre if you want to fill your tyres with nitrogen. They cost like RM40 in some places for the whole car. I’ve had family members who agreed to this, and the truth is, it is a waste of your money.
Let me explain.
Nitrogen-filled tyres are usually indicated by green dust caps. Image Source
Q: First, what are the benefits of filling your tyres with nitrogen?
A: For normal driving, it keeps your tyres inflated longer since the bigger molecules don’t escape so easily to the porous tyre material. Apparently, nitrogen molecules are bigger than ‘normal air’.
That is all.
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As for other more demanding applications, using nitrogen makes a lot of sense:
Dry nitrogen mitigates tire pressure variations, so nitrogen-filled tires are also used in professional race car driving, where even the smallest changes in pressure can impact ultra-high-performance vehicle handling at extreme speeds.
Thanks to its inert properties, nitrogen filled tyres are also excellent for applications in aviation, mining, and construction.
‘Normal Air’ Is Already 78% Nitrogen
Now, there’s one fact we’re kind of ignoring here – ‘normal air’ is already 78% nitrogen. You’re already filling your tyres with mostly nitrogen usually anyway.
‘Nitrogen tyre refills’ are basically just 93-95% nitrogen
That 15-17% increase makes a very small difference, if any.
At best, nitrogen-filled tires lose 0.33-0.67 PSI/month instead of the usual 1-2 PSI/month.
But hey, if you feel that is worth your money, go ahead and fill up with nitrogen
Q: Does Filling Your Tyres With Nitrogen Help Improve Fuel Economy?
Under-inflated tyres will give you poor fuel economy. That is all. The logic of using nitrogen is that since you lose pressure slower, you will drive at a better fuel economy rate.
If your nitrogen-filled tyres are under inflated, you will still get poor fuel economy.
It does not make your tyres lighter (nor does it reduce rolling resistance).
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Tyre Punctures Are A Common Occurrence
Tyre punctures happen more frequently than we expect.
Unless your car is equipped with TPMS (Tyre Pressure Monitoring System), the best practice is to check your tyres as frequently as possible (weekly/monthly) at the petrol station.
It is common to realise a slow puncture too late only to find one tyre being severely worn out compared to the others.
Make it a habit to monitor your tyre pressure
Filling your tyres with nitrogen may give you a false sense of security that your tyres are always properly inflated.
Nitrogen-filled tyres certainly have benefits for demanding applications, but don’t offer much benefit for the average city car.