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Last Updated On December 7, 2020

Ever Wondered What Those Green Valve Stem Caps On Car Tyres Mean?

What is the difference between nitrogen and filled tires? More importantly, should you fill your tires with nitrogen or air? This question wasn’t that important a decade or two ago because air was the only significant option on the market.

Today, using nitrogen has attracted a lot of interest, growing in popularity among civilian drivers and even racers, which is why so many people are starting to question whether using nitrogen is superior to air.

So what do green valve stem caps mean?

Macro view of wheen and green valve

So if you ever see green caps, that the filled tires are full of nitrogen and not regular air. In case you have an emergency, you can fill it with regular air. But once you get back to the service station that filled or mounted the tires, you’d want to tell them to go ahead and refill it with nitrogen and get rid of all the air.

Nitrogen filled vs air filled tires whats the better option?

Most professionals argue that nitrogen is the better option, but is this actually true? The popularity of nitrogen can be imputed to the numerous benefits it offers, most of which make it a far more appealing option.

For instance, nitrogen molecules are not only bigger but they migrate at a slower pace than their compressed air counterparts. This matters because, like air, nitrogen will eventually escape from your tires but it will do so at a much slower rate, allowing your tires to maintain their pressure for a considerably longer time.

You may save a few dollars on fuel from better efficiency

Since nitrogen doesn’t migrate through the tire as quickly as oxygen, your maintenance costs will fall because you don’t have to check your tire pressure as frequently, and neither are you expected to refill your tires as incessantly as compressed air demands.

In the long run, the stability per tire that nitrogen offers is going to contribute to your fuel economy, not to mention enhancing the lifespan of your tires.

Nitrogen can give you an edge on the track

For racing experts, this benefit is especially useful because it means that their cars will operate reliably on the road for longer periods, with the pressure remaining stable regardless of the wild swings in temperature that can happen when a race car’s tires heat up.

If that hasn’t sold you on nitrogen filled tires, you should also know that the gas is inert, that is to say, it doesn’t have any other particles. The nitrogen a professional will pump into your tires is not only pure but dry.

It is devoid of water molecules that would normally corrode the aluminum components per tire, which is why it is promoted as a corrosion-free gas.

Repels water vapor and lengthens wheel lifespan

It is also worth noting that any system that fills tires with nitrogen will initiate a process that will push the gas into the tire whilst also diluting the oxygen concentration, an act that removes any water that might be present to minimize the corrosion suffered by your wheels.

If you want to know how air compares, the substance consists of nitrogen (78 percent), oxygen (21 percent), water, carbon dioxide, and some noble gases.

The presence of water in a tire’s compressed air is problematic, not only because it corrodes the rim but also because the temperature swings that occur cause a more drastic pressure change.

A few things to mind before you add air

Some agree that air cannot provide the same stability you find in nitrogen filled; though, a lot of people still use compressed air because it is easily accessible, not to mention free.

As you can guess, nitrogen loses out in these sections, especially in certain regions where it is not only expensive but slow where the inflation of tires is concerned.

Why you don’t want to put regular air in that valve stems? So any valve cap that is green normally means has been filled with nitrogen.

So this particular car, I had regular air in there and I twenty thousand miles, whether it was a tire defect or whatever it was, the tire blew out.

How to check your tire inflation pressure

And in case you guys don’t know how to check your tire inflation pressure or how much you should have in the car on all cars, and about 90 percent of them are going to be right here in the doorjamb.

So on a 2020 Toyota Prius, 2016 Toyota Prius, the front are going to be at 36 in the back are going to be at 35 in the spare. This one does actually have a spare, it’s going to be at 60.

If you have one you should reset the Tyre Pressure Monitoring System (TPMS) line in case you get it.

But in case you have it, just put it back to the desired to the recommended pressure and then I’ll have a link to the other video as far as how to reset the TPMS light.

Will nitrogen tire inflation explode?

The misconception is, if you had nitrogen in your tire, if you go out and you lose a little air in your tires is that you can’t afford regular air, which is false.

You can add regular air to a car that has nitrogen in the tires and does not blow up. It just depletes the nitrogen percentage, which has, you know, it’s not as effective, but that’s all it does.

It’s not a danger. A lot of people think nitrogen blows up, but it doesn’t.

In summary

  • Green caps mean nitrogen filled tires, the advantage of having the nitrogen filled tires is the nitrogen is less likely to migrate through the rubber.
  • If the cap is gray (or black) and matches the hubcap it means it’s just regular compressed air, not nitrogen.
  • Your tire pressure will actually remain more constant than if you have regular air tire inflation so the nitrogen does work.
  • The another reason that they use a certain percent nitrogen tires is because it responds less to changes in temperature.
  • So hot air versus cold air will condense or expand, but nitrogen will change its volume or pressure less than regular air.
  • Overall, the nitrogen in the tires is more stable. It helps stabilize the pressure. So that’s useful. You can identify tires with nitrogen.
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