Is nitrogen really better than air at prolonging tire lifespan?
Putting nitrogen in automotive tires isn’t exactly a modern and innovative idea. Race cars have been doing this since the 60s and airplanes for far longer (because nitrogen doesn’t expand as much at high altitude as regular air).
Come back down to sea level, and we’ll tell you what happens with nitrogen when it’s in your tires.
Nitrogen molecules are about 3% bigger than regular air molecules. That's not a lot, but it's enough to reduce the amount of seepage through the valve or the sidewall by about 30% compared to regular air. Don’t get us wrong though, you’ll still lose tire pressure, but at a far lesser rate than regular air. Still, this is no excuse to skip regular tire maintenance. In case you haven’t yet, read our article about tire inflation.
In our tropical climate, heat is a problem, especially for the air in your tires. The hotter it is, the higher the air pressure goes. Really smart people called ‘scientists’ say that every time the mercury goes up by 12° Celsius, tire pressure expands one pound per square inch (PSI), and vice-versa. Unfortunately, nitrogen reacts to heat the same way as all other gasses negating any real advantage over regular air in this regard.
Pure nitrogen is a dry gas and does not support moisture. If there is no moisture, your wheels will not be susceptible to rust and corrosion. But, and this is a very big but, it has to be pure nitrogen, which means there shouldn’t be any mix of water/moisture or regular air in the tire. The shop must know (or ask them) to remove all the original air through bleeding (at least a few times) to make sure only pure nitrogen is in your tires. If they don’t, then you’re just getting a mixture of nitrogen and regular air.
That’s really where the dilemma lies because regular air is about 78% nitrogen, 21% oxygen, and a 1% mix of other gasses. Either way, you’re getting a lot of nitrogen in your tires already.
Now for the benefits of having nitrogen in your tires. You’ll have stable tire pressure for longer. That will mean fewer trips to the pump and less time spent inflating tires.
Because pressure is more consistent, the tires will exhibit less rolling resistance. The result is improved fuel economy.
Properly inflated tires will be more effective in providing grip and traction. No, it won’t feel like a Porsche 911 all of a sudden so lower your expectations. But do know that it will help your tires perform at their very best.
Without moisture or water vapor in your tires, there are fewer chances for the wheel, valve stem, and sensors (for models with TPMS) to corrode.
Here’s the reality check.
If your tires are in tip-top shape, these shouldn’t be leaking any more than 1 PSI a month. Simply follow proper tire maintenance and this won’t be a problem.
Just because it leaks less, doesn’t mean you don’t need to top up. You’ll still need to take time out of your busy day to add more nitrogen. These trips though will be few and far between.
Moisture is still present outside your tires and is still constantly causing iron particles to oxidize and form hydrous iron oxide, more commonly known as rust. So yeah, your wheel is still slowly rusting, but from the outside.
And then there’s the cost. While it may still be relatively cheap for most motorists (Php 100 per tire at the start and free for all successive top-ups) the time, trip, and traffic to the nitrogen pump is the far bigger consideration.
As we’ve laid out, yes, there are benefits, but extremely minimal. If it’s for your daily drive, your tires and wheels may naturally degrade due to normal use and be replaced before you even see the benefits of using nitrogen.
These are the facts. Up to you to decide if all that is worth the drive to the nitro pump.