Advantages of Nitrogen Filled automobile tires

Nitrogen element properties
Problem: Tire pressure escapes over time
Cause: Oxygen leaks out, Temperatures change
Application: All models
Solution: Filling tires with nitrogen
Where to buy: Dealerships, tire shops
Cost: $5 - $10 per tire

Tires are commonly filled with compressed air, but recently there has been a lot of talk about filling automobile tires with pure nitrogen.  Nitrogen filled tires are found in many industries such as aviation (commercial and military), heavy duty construction vehicles and even Formula 1 teams, who all have all been benefiting from the use of nitrogen filled tires.  Even the new Nissan GT-R comes delivered from the factory with nitrogen filled tires.  So what are the benefits of filling your tires with pure nitrogen instead of oxygen?

The air we breath is primarily made up of 78% nitrogen, 21% oxygen an 1% miscellaneous gasses.  When this ambient air is compressed and filled in rubber tires, the 21% oxygen has destructive properties to the rubber and wheels.  Oxygen holds moisture which causes corrosion to the rubber, forming cracks and losing elastic properties.  Oxygen also accounts for major pressure changes due to temperatures swings.  Like all gasses, oxygen expands when heated and contracts when cooled. The rule of thumb is 1 psi of pressure per 10 degrees F of temperature change.  So now that we know oxygen is the culprit in poor tire pressure performance, we need to remove it and add more nitrogen.

The nitrogen levels found in air, 78%, need to be raised to a 95% minimum to be considered "pure" which will allow you to have many benefits over compressed air.  Below is a list of benefits of using nitrogen filled tires instead of compressed air.

  1. Works with any current tire / wheel setup, no modification needed.
  2. Nitrogen is a completely inert, safe gas: non combustible, non corrosive & non flammable.
  3. Nitrogen will help you maintain constant pressure in any temperature swing (ideal for racing).
  4. Nitrogen will not dry and crack your rubber tires from the inside.
  5. Nitrogen will not corrode your wheels like compressed air will over time.
  6. Nitrogen will not escape out the small cracks in your rubber tires.
  7. Longer tire life.
  8. Safe to top off nitrogen filled tires with compressed air in emergencies.
  9. Improved fuel economy with constant pressure.
  10. Improved TPMS readings.

How do I know if my tires are filled with nitrogen already?

Maintenance shops which fill tires nitrogen should install a GREEN valve stem cap on the tire to denote a nitrogen filled tire. See image below for clarification.

BMW green nitrogen caps
BMW M6 wheel composite brakes