Re: Nitrogen in tires
I've been following this thread with interest since it was initiated. I'm always interested in learning what others know about vehicles, control systems, and machinery in general.
I've resisted bringing up the Ideal Gas Law because I wanted to see/read the observations of the forum posters rather than telling anyone what is or isn't possible according to physics theory. But now the cat is out of the bag, set loose by Bruce.
The Ideal Gas Law states that an increase in temperature (Kelvin), with volume held constant, will result in a proportionate increase in pressure. It applies to all gases equally - well, almost equally. The differences in response among gases is measured in thousandths of a percent - low enough to be considered insignificant for most purposes.
Therefore, dry air will have essentially the same contraction/expansion characteristics as dry nitrogen with varying temperature.
Secondly, air is about 78 percent nitrogen. (With 21 percent oxygen and 1 percent trace gases - CO2, argon, and the like) It's difficult for me to see how an air molecule can be smaller than a nitrogen atom and escape through the tire wall more easily.
HOWEVER -- the respondents to this thread have noted the use of nitrogen in aircraft tires and in other critical applications. I'm sure this is not done lightly - that there is a good reason for this.
I just don't think I've heard it yet.
