Nitrogen in Trailer Tires

ktmrfs wrote:

mike-s wrote:

mat60 wrote:
Back in the day I raced stock cars and we used nitrogen in our tires thinking it would help slow down the expansion of the tires as they build heat.

Nitrogen obeys the same gas laws as other atmospheric gases. There is absolutely NO difference in heat expansion.

What does make a difference is moisture, which you also get from air. Industrial grade N2 might have 5 ppm of moisture (~0.03% relative humidity @ 70F). Even dry desert air might have hundreds of times that. For today's Daytona race, right now it's 73F and 72% RH. That's ~12000 ppm moisture.

Compressed N2 can simply be a more convenient source of dry gas than a compressor and good dessicant dehydrator. Nitrogen is just the cheapest compressed dry gas available.

exactly!!! If you used dry air, the effect would be almost identical to nitrogen. but as you mention dry nitrogen is cheapest and easiest way to get a dry gas source.

Race teams use it because (a) it is dry and (b) it is consistent.

One small advantage is that the nitrogen molecule is slightly larger than Oxygen, even though the molecular weight is less. That means pressure loss over time will be SLIGHTLY less. not enough to justify it's use alone.

Pass air through the right membrane and all the oxygen and water will go through and all your left with is nitrogen. also a nice way to make an oxygen concentrator.