Nitrogen Air in Your Tires: Does it Save Gas?

Haus of Cars is committed to meeting the automotive needs of our customers within and beyond Greater Vancouver. And we would like to clear up the controversy for our customers about using ordinary atmospheric air versus pure nitrogen in tires. The belief is that using nitrogen will save you money on fuel bills and that this gas is worth a premium price in your tires. The truth is not so black and white, as explained in greater detail below.

 

The Science of Air and Nitrogen – What’s the Difference?

In truth, there is very little difference. The ordinary air that we breath is 78 percent nitrogen. If the oxygen levels were any higher than the standard 21 percent, we would live in a barbecue pit from all the spontaneous combustion that a high-oxygen atmosphere promotes. The other one percent of the air we breathe is composed of water vapour, carbon dioxide, and traces of the inert gases argon and neon. City pollution will increase the levels of carbon monoxide and other greenhouse gases in this mix.

 

Why is Nitrogen Purity Advantageous?

Pure nitrogen is less likely to escape from the tires and will maintain the same pressures even during temperature changes. Moisture from the water vapour in ordinary compressed air can cause internal corrosion and make tire pressures unstable when the temperatures change.

 

The subtle advantages of using pure nitrogen are more obvious in a race-car. You will always hear the commentators discussing tires and track temperature. It is important for pit crews to dial in the exact air pressures. They want to fine-tune the handling of the vehicles at this speed by even maintaining it to a half bar.

 

For ordinary consumers, nitrogen-filled tires are a double-edged sword. In one respect, they can maintain consistent tire pressure but may also cause them to become lackadaisical about checking the pressure. Nitrogen-filled tires are probably the better choice for drivers who have tire-pressure monitoring systems and simply don't want to deal with the hassle of checking and filling their tires.

 

If you are someone who doesn't like to get their hands greasy, or someone who is just too busy to keep an eye on their tires, pure nitrogen is a good choice. However, when your tires are running low, you might give a second thought to filling them with regular compressed air. Too much regular air will make the nitrogen conversion ineffective.

 

If your tires tend to deflate at the bead or the stem, then nitrogen may not provide any advantages at all for a slow leak. Its only advantage is when you have new high-quality rubber tires that go through a lot of temperature extremes. Especially in a Canadian winter, the temperature changes when the vehicle is sitting and then driven on the roads when the tires heat up.

 

Can Nitrogen be Used to Fill Any Tire?

Short answer, yes. In order for nitrogen to be effective, the nitrogen must reach levels of 93 to 95 percent in purity. This means that all your tires have to be deflated and re-inflated with nitrogen numerous times to complete a full conversion. Shops can charge one or two hours of work at $100 to $200 CAD.

 

Can Tire Pressure Effect Fuel Efficiency?

Yes, but if in the optimal range, the difference in fuel economy is negligible.  You will probably improve your fuel economy better if you invest in gas saver tires with a low rolling-resistance (make sure to do your research however, as some low resistance tires degrade braking performance). Keeping up auto maintenance is also more important for fuel economy than tire pressures.

 

Air leaks in the engine bay and exhaust system can all have a serious impact on fuel consumption. If your vehicle is making a lot of noise when you start it up, you probably have an exhaust leak. If the engine seems to shake at idle, this would be evidence of vacuum (air) leaks in the engine bay.

 

Your oxygen sensors, mass airflow sensor, manifold absolute pressure sensor, fuel injectors, air filter, and ignition system have a much greater impact on fuel usage than difference in recommended tires ever could. And of course, one of the greatest impacts on fuel is simply how you drive your vehicle.

 

If you drive aggressively by braking and pulling out hard, this will put wear and tear on your vehicle as well as wasting fuel. Using air conditioning will also bog down your engine and transfer less rotational power to the wheels, and still worse yet, rolling windows down when in motion cause huge drag on aerodynamics. This is a huge gas eater.

 

Conclusion

Airplanes, spaceships, industrial vehicles, and racecar tires operate under extreme temperatures and duty cycles. The average consumer may not see any benefits in using pure nitrogen as opposed to air taken straight from the atmosphere. All tires will release air and lose pressure over time. And the differences between air and pure nitrogen are inherently negligible. When you consider the high costs charged by many shops to fill tires with nitrogen, it is rarely worth it in the name of fuel savings or convenience alone.