What’s the big benefit? Tire inflated with Nitrogen loses its pressure three times slower compared to one inflated with compressed air. Diffusion out of the tire sidewall is 30 to 40 percent slower than Oxygen. That’s why a Nitrogen-filled tire maintains pressure longer. For cars with (expensive) custom alloy wheels, an even bigger benefit could be the fact Nitrogen prevents oxidation (due to the lack of water). Oxidation leads to tread separation, but it also leads to corrosion of the rim. Don’t believe it? Forget to drain an air compressor after a few days of use and you’ll see just how much water is found in good fashioned compressed air. Proponents of Nitrogen-filled tires point out that Nitrogen maintains pressure much better than compressed air. Proponents of compressed air point out it isn’t difficult to check and refill tires, even on a weekly basis.
Nitrogen proves largely inert, from a chemical perspective at the relatively low operating temperatures experienced by automotive tires. That means Nitrogen will not attack the rubber in tires like Oxygen does. Keep in mind that many tires use steel belts. The steel, obviously, is not immune to attack by moisture in found in compressed air.
Another benefit proponents of Nitrogen note is the fact Nitrogen is slightly lighter than air. In theory, this will reduce unsprung weight and the car will exhibit better performance. There is a catch however: The weight difference we’re discussing works out to less than 4% of the gas in the tire. That calculates to a reduction of less than an ounce for most vehicles. Whether this is beneficial or not might be a moot point, particularly in a street-driven cars.
Nitrogen, which doesn’t escape easily from the wheel and tire combination can obviously contribute to stabilized tire pressures. But on the other hand, so can weekly tire pressure checks a job that certainly isn’t difficult, and something anyone can accomplish. In the end, is Nitrogen for you? It’s your call, but at the very least, check tire pressure regularly.
