Proponents seem to base claims on fully nitrogen inflated tires compared to under-inflated air filled tires

This is NOT a reasonable comparison. The exact claims could be made for a tire properly inflated with air, compared to one under-inflated with nitrogen. The basis of the claims seems to be, air leaks out of tires and nitrogen does not, or at least, does not leak as quickly.

All tires loose pressure over time, nitrogen or air filled

Nitrogen molecules are slightly larger than oxygen molecules. For this reason, nitrogen proponents claim they leak less. In fact, at best, only the 20% oxygen content could possibly leak faster. Test show, at most about 4 PSI a year difference. Tire dealers normally rotate tires they sell, often free of charge. Checking and properly inflating tires should also be included.  Most people rotate at least twice a year and will notice no difference using air or nitrogen.

It is also a fallacy that tires are being inflated with pure nitrogen. The inside chamber of a non-inflated tire is filled with air at atmospheric pressure. If not the tire would collapse. This air, with about 20% oxygen, remains in the tire and nitrogen is simply added to fill the remainder. This is not filling with pure nitrogen.  Even filling and purging the tire several times will not result in pure nitrogen content.

A punctured tire will deflate, nitrogen or air filled

Flats are a part of life and it is not always possible to immediately have the tire repaired. Nitrogen proponents may suggest air should not be added to the tire as it defeats the nitrogen fill. This can create a dangerous under-inflated situation if nitrogen is not available to refill. In fact, air can be used to inflate the nitrogen filled tire. This is far wiser than operating an under-inflated tire.

A properly mounted and balanced tire, using a quality valve stem is far less likely to leak than a poorly mounted tire with a cheap valve stem. This is just as likely with air or nitrogen.

Occasionally checking and properly inflating tires WILL

•  Extend tire life, with air or nitrogen
•  Lower rolling resistance, with air or nitrogen
•  Slightly increase fuel mileage, with air or nitrogen

When compared to an under-inflated tire, with air or nitrogen

Don’t wallet flush your tires, save your money. That’s the AGCO way, no tricks, no scams, just quality auto service and overall lowest cost.

For additional information on nitrogen for tires, please also see our Detailed Topic, The Nitrogen Inflation Fairy Tale.