Nitrogen or Air

 For many years now, nitrogen has been used to fill aircraft tires, including the Space Shuttle’s and also tires on race cars, but it’s use on street cars is relatively new and somewhat controversial.
The tire shop will tell you that nitrogen in your tires:
- Improves steering
- Improves handling
- Improves braking
- Reduces the chance of tire failure
- Dramatically slows pressure loss from permeation
- Improves fuel economy
- Reduces tire oxidation
- Eliminates interior wheel corrosion
- Reduces running temperatures
- Decreases false alarms and activation of your TPMS (tire pressure monitoring system) Nitrogen molecules (N2) are larger than oxygen molecules (O2) so therefore, pure nitrogen will permeate the walls of your tires less than oxygen molecules.