Nitrogen vs Air in Tires

Nitrogen vs Air in Tires (is there really a difference?)

Nitrogen is becoming more popular as a gas to fill tires in place of regular air. But don’t assume that it will work for you just because it works for other people. One of the advantages of nitrogen is that it may help your tires remain inflated for longer. That is because on a molecular level, nitrogen moves more slowly than the compressed air typically used to fill tires. The nitrogen molecule is also larger than regular air, which helps with this effect as well. In today’s article I’ll provide an in-depth comparison between Nitrogen vs Air in tires to explain all of the benefits (and drawbacks) of each, and help you decide which will work best for your vehicle’s tires. 

Let’s start with some of the basics.

Why Do People Choose Nitrogen instead of Air?

The primary reason why people choose to fill their tires with nitrogen vs air is that when you fill your tires with nitrogen, you may be able to maintain correct air pressure for longer without having to re-fill.

So what?

Inflating Tires with Nitrogen vs Air - What Are the Differences & Why Do They Matter?

Well, the benefits of this extend beyond simple convenience (not having to correct the pressure in your tires as often).

  • First, by maintaining the right pressure you will improve the durability of your tires. They’ll wear more evenly, and you probably won’t have to replace them as often.
  • Secondly, nitrogen-filled tires may also help with fuel consumption, saving you money on gas or diesel for your vehicle.
  • And finally, properly inflated tires can also improve your driving experience and your car’s performance (and safety) in inclement weather.

So there’s more to this than meets the eye.

Air vs Nitrogen (which should you choose & why?) 

First of all, don’t worry if you just want to stick with regular air for your tires. That is perfectly fine. Most of the vehicles you see on the road have air in their tires and not N2.

However, you should be aware of the differences between nitrogen and air in tires. That way you can make the best (informed) decision for your vehicle, lifestyle, and preferences. 

Air vs Nitrogen in Tires

One downside to filling your car tires with nitrogen is that it is usually more time-consuming. This is because fewer service stations offer N2 so you’ll have to find a local service station where you can get Nitrogen for your tires. It will usually be pricier, too.

This is why an advantage of regular air vs nitrogen in tires is that it’s so easy to find a place that has compressed air. And if you own a compressor then you can top up your tires right in your driveway or garage.

Also, air is typically free of charge (I’ve been breathing air for years and have never paid a dime!).

Reasons to Choose NitrogenReasons to Stick with Compressed Air
Improved tire performance, longevity, and you won’t need to check the pressure and re-fill your tires as often. It’s usually free, and it’s more convenient (there are fill stations everywhere).

How Tire Performance Changes When You Use Nitrogen vs Air in Tires

If you want to try using nitrogen, be aware that the performance of your tires will be different if you use that instead of regular air.

Did you know that airplane tires are filled with nitrogen? This is because of how well it deals with drastically changing temperatures and weather. The nitrogen in the tires will be better able to deal with that. As a vehicle owner, however, you probably won’t have to worry about this (unless your car flies, in which case you’re probably reading the wrong blog).

That is because nitrogen doesn’t entirely get rid of pressure changes when you are driving in average conditions. Some instances where you may see a difference is if you live or work at elevation and are regularly driving up and down mountains where pressure and temperature changes are significant.

But even for the average commuter, there are still benefits to inflating your vehicle’s tires with N2.

Is Nitrogen Really That Different From Air in Car Tires?

When you fill your tires with nitrogen, it will be longer before you will have to deal with any pressure loss. The nitrogen won’t be able to escape as quickly as regular air will.

Some Interesting Facts About Tire Pressure

It may surprise you to learn that many car and truck tires lose about 5-10% of their pressure every single month. That’s why most mechanics recommend checking your tire pressure monthly.

What’s more, under-inflated tires can increase your gas consumption by up to 4%, which means that if you spend $50 a week on gas you could save $104 every year if your tires were properly inflated. Add to that extra cost the cost of replacing your tires more often and the reduced grip and performance in inclement weather you’re suffering with improperly inflated tires, and suddenly the cost of inflating with N2 doesn’t sound so bad.

The bottom line is that the stability in tire pressure that nitrogen provides can help lengthen tire life and give you improved gas mileage. 

Some Interesting Facts About Tire Pressure and Why Maintaining the Correct PSI in Your Tires Matters

Some drivers, however, feel that it’s not worth the cost involved to use nitrogen in their tires, and in many cases they’re right.

If you are an average commuter, and usually drive in safe conditions, you are likely to feel this way, and as long as you check your pressure and top-off your tires with air (for free) every month, you’re good.

So, How Does Nitrogen Work in Tires Exactly?

As we mentioned before, nitrogen molecules are bigger than air molecules.

This larger molecule size makes the N2 gas less likely to leak from your tires. It’s because of this that tires filled with nitrogen tend to lose their pressure more slowly than ones filled with air.

As properly filled tires create a smoother ride, there’s a strong chance you will get superior fuel economy. Nitrogen may also help your tires last longer, as properly inflated tires will wear more evenly (which extends tread-life). 

Ok, But Should You Put Nitrogen in Your Tires?

When you fill your tires with regular air, they will usually lose between 1 and 2 PSI of air each month under regular use. PSI stands for pounds per square inch. When you go with nitrogen, you will lose less pressure.

That said, the savings isn’t as much as you might think. A Consumer Reports study found that when tires are inflated to 30psi and left outside for a year nitrogen-filled tires only lose approximately 1.3 PSI less during one year than tires filled with air. My guess is that the difference would be greater under regular road use, but I was still surprised that the difference was so low.

Difference Between Nitrogen and Air in Tires

And it should be noted that dry air is already 78% nitrogen, 21% oxygen, and 1% other gases. So the difference when you get the green cap on your tires is actually that you’re adding 95%+ nitrogen instead of 78%. 

If you’re willing to accept the extra cost of filling your tires with nitrogen instead of air, go ahead and try it at least once. See how you like it and decide from there whether you will do it again.

Can You Use Nitrogen and Air at the Same Time? 

While you shouldn’t go out of your way to try to mix nitrogen and air in your tires, you can mix them if you need to. An example might be if you notice your N2 filled tires are low and need to inflate them ASAP.

There’s no need to wait until you can access nitrogen. You can just add some compressed air until your tires are properly inflated again.

It’s important to know this, as it can be dangerous to drive with under-inflated tires. Even one improperly inflated tire can cause problems.

Inflating Tires with Air or Nitrogen - Can You Mix Air and Nitrogen in Car Tires?

While there’s no danger to mixing nitrogen and air in your tires, you will lose some of the beneficial effects of nitrogen for the tire. But even in an article comparing nitrogen vs air in tires, the reality is that once you add N2 to your tires you can easily go back to air.

Does Using Nitrogen Help Stop Tire Rot? 

Unless your car is being kept under unusual conditions (for example, if you hardly ever drive it for long periods of time), you probably don’t need to use nitrogen to avoid tire rot.

Most vehicles that are driven regularly won’t end up with rubber rot problems, regardless of how you inflate your tires. 

Rubber rot is caused by moisture accumulation within tires. When rubber rot takes hold, it will start breaking down the tire’s rubber.

But let’s say you own a classic car that is rarely driven with expensive tires. They may be prone to rubber rot, and you should try using nitrogen. This is because of how “dry” nitrogen is in comparison to oxygen.

While nitrogen is a component of regular compressed air, compressed air includes oxygen, water vapor, and other components. These can contribute to rubber rot. 

How Can Oxygen Damage Tires?

Of course, there is oxygen in the regular air you usually use to fill your tires. While most people always use regular air instead of nitrogen to fill their tires and never have any damage, it’s true that oxygen may react negatively with rubber. 

Comparing Nitrogen vs Air in Tires - Flat Tire

When this happens, there is a thermo-oxidative reaction that leads to rubber degradation. This is usually something that happens over long periods of time with old tires. The presence of oxygen can lead to oxidation, and this may eventually lead to brittle rubber. 

There’s no need to worry about oxygen damage in your tires if you are just a regular driver. In the vast majority of cases, you will have to replace your tires before there is any chance at all of oxidation damage. After all, tires need to be replaced on a regular basis, and there are many other factors (such as general wear and tear) that will damage your tires before oxygen damage could ever be a problem for you.

Why is Tire Pressure So Important? 

The most important part of keeping your tires in good shape is keeping up proper tire pressure. No matter whether you fill your tires with nitrogen or air, keeping the right tire pressure is key to making sure your tires handle in the right away and have even tread wear. 

Good tire pressure also boosts fuel economy, as I mentioned earlier, and it can make your vehicle stop more rapidly and keep your family safe.

Why Maintaining Tire Pressure Matters

Different vehicles may require different tire pressures. Check to find out what the recommended pressure is for tires on your vehicle. Many cars have this information on a sticker where you close the driver’s side door. You can also check your owner’s manual. 

Why is Nitrogen Used for Race Car Tires?

Did you know that race car tires are filled with nitrogen? This is because of how consistent nitrogen keeps the tire pressure. Another reason why nitrogen is favored for race car tires is how it isn’t as impacted by temperature changes as regular air. 

Sometimes the tire pressure warning in a regular car will come on when the temperature suddenly changes. An example is when the fall arrives and the temperatures suddenly drop. Race car drivers don’t have to worry about tire pressure in these circumstances, as they have nitrogen in their tires. 

For obvious reasons, race cars aren’t able to stop and re-inflate their tires while on the track. Filling their tires with nitrogen means that tire pressure will never be an issue, even as their tires heat up after a series of high-speed laps.

Properly filled tires ensure that race cars are able to perform optimally at all times. 

The Biggest Complaint? N2 Can Be Hard to Find

You will have to find a gas station or garage with a nitrogen filling tank. This may be more difficult than you anticipate. However, some drivers find it worth the hassle. Most drivers like that when they fill their tires with nitrogen, they won’t have to refill them quite as often. 

A Green Cap Indicates this Car Tire was Inflated with N2

Something to be careful about if you decide to get nitrogen in your tires is assuming that you’ll never have to check your tires. Once you fill tires with N2 your tires will still lose pressure over time.

You should still check your tires and air pressure on a regular basis. The only difference is that you probably won’t find low pressure as often as you might with air, so you may need to top them up every other month instead of every month. 

Why Tire Maintenance is So Important

Even after comparing Nitrogen vs Air in tires and making your decision, proper tire inspection and regular maintenance are essential to both performance and safety.

Some drivers who use nitrogen make the mistake of thinking they never have to worry about their tires because they have nitrogen in them. This is not true. You still must check your tires and maintain proper pressure exactly as you would if they were filled with compressed air from your local service station. 

Making sure that your tires are properly inflated at all times is one of the most important parts of keeping them in good shape. Tires that are under-inflated (or over-inflated) will not last as long, will not give you the steering, braking, and acceleration performance you expect, and will certainly be a liability in inclement weather. 

Family Road Trip

I recommend that you check your tire pressure every month, and don’t do it right after you drive. Wait for your tires to get cool after sitting in the driveway for a while.

My Recommended Tire Pressure Gauge

Recommended Tire Pressure Gauge

I use a simple tire pressure gauge made by Vondior (Amazon link) with a brass bleeder valve that allows me to easily let some air out to achieve a perfect PSI reading after filling my tires with my compressor. It has held up well for years.

I used to have a more expensive digital gauge that hooked right into my compressor, but the connection wore out within a year and it wasn’t quite as accurate as this one. Sometimes the simplest tools work the best, and if you’re looking for a good option for around $15 (or less if it’s on sale), I recommend it.

Also remember all the other elements of tire maintenance, including regular tire rotation, ensuring tires are balanced, and getting regular wheel alignments as prescribed by your mechanic (I try to do it 2x each year).

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