Sharing the claimed benefits of using nitrogen:
Increased Fuel Efficiency – Correct tire pressure keeps the manufacturer's recommended “contact patch” on the road. This lessens the rolling resistance and maximizes fuel efficiency.
Longer Tire Life – When it comes in contact with other materials, oxygen causes oxidation. Oxidation can make rubber brittle and cause it to lose tensile strength. In addition, at high temperatures and pressures, oxygen reacts and damages inner tire liners and belt packages; nitrogen does not.
Increased Safety – Under-inflated tires cause 90% of blowouts. Nitrogen provides more reliable pressure for reduced blowout potential.
Other benefits:
Improved TPMS Performance – If you have a new car, you likely are plagued by a flashing light telling you your tire pressure is low. For example, one person's light was going off every four to five weeks. After inflating with nitrogen, his light didn't reappear for 53 weeks!
More Predictable Pressure Fluctuation – NASCAR teams use nitrogen so they can more accurately predict tire pressure fluctuation. Regular compressed air can fluctuate considerably when water vapor is present. Read On...
Longer Rim Life – Rim rust caused by condensation from water vapor and other gases can get caught in valves and create slow leaks in tires. Nitrogen is completely dry, so it eliminates the potential for condensation.
Some real life data:
Fleet 48% cost savings and 45% tire life increase - Data from a private South African company Amalgamated Bulk
Fleet 82% reduction in tire repair cost. 26.6% fuel savings - Feedback from a private fleet company Larsen Trucking
Fleet Decreased number of blowouts. Approximately 40% tire cost decrease. - Feedback from a private fleet company Larsen Trucking
Source:
http://www.getnitrogen.org/savebillions/index.php