The air that we breathe is about 78% nitrogen and 21% oxygen. The rest contains small amounts of other gasses and water vapor. This is the same air that is generally used to fill tires. There are several advantages to removing the extra oxygen and other gasses from your tires.
Have you ever gone outside on a particularly cold day and noticed that your tires look lower than they did the day before? That’s because temperature change affects tire pressure. The oxygen in your tires expands and contracts when the temperature rises and falls. You can expect an average change of 1 PSI for every 10°F change in temperature. Filling your tires with nitrogen can greatly reduce these pressure changes. Nitrogen molecules are less susceptible to temperature changes than oxygen molecules which means they maintain a more consistent pressure in all weather.
Tires filled with air also lose about 1 PSI each month because oxygen slowly leaks out through the rubber of the tires. Nitrogen molecules are much larger than oxygen molecules so tires filled with nitrogen will lose far less pressure each month.
Finally, the nitrogen used to fill tires is dry. There is often water vapor in the air used to fill tires. This can build up inside tires and cause damage to the rubber from the inside. Filling your tires with nitrogen eliminates this moisture build up.
What does all this mean? You save money! When your tire is filled to the recommended pressure you can improve your fuel economy by up to 3.5%. If your tire is filled with nitrogen it will maintain the correct pressure longer. Nitrogen makes saving money easy!