What are the advantages of using Nitrogen gas to inflate tires?

(Sorry, it's not very S2000-specific)

 

I first heard about this trick at the TWS event last month. It was described as 'the trick that everyone knows about and no one talks about'.

When you inflate your tires with Nitrogen, the pressure will never increase nor decrease, so there is no need to constantly check the pressure. One individual also stated that even if you ever need to add a bit of air in the Nitrogen inflated tires, that will be fine too.

Anyone else know any further details (if any) on the subject?

 

I do know that nitrogen is used in the tires of the giant earth moving equipment to stabilize pressures. I visited a coal mine some years ago and was asking about the trucks with wheels so big I could only reach up to the hub and that was one of the interesting things I learned. I never thought much about using nitrogen in the car tires .. hell, it

 

Hmmm ... so you guys are saying that Nitrogen *doesn't* behave like other gasses, on other words, following the ideal gas law pV = nRT? (to bring up some physics p = pressure, n is "amount" of gas, in number of molecules, V is volume, T is temperature and R is constant).

Unless I'm mistaken, increasing temperature without changing volume should increase pressure, for a given volume, regardless of whether it's nitrogen, helium, air, whatever. Would someone clarify this, or is it simply a myth? (or do I now have a hook in my mouth? <G>)

BTW, this formula/theory is what makes our cars g. The combustion of the fuel-air mixture simply raises the temperature of the gasses, which in turn increases the pressure, which drives the piston down.

 

Just when you think you've heard it all...

 

you forget that the T is actually delta T(change it T) Nitrongen have a very high specific heat capacity so thats why its pressure doesnot change readily.

 

Is it me, or does it seem that the smartest S2000 owners have the white/red scheme?

 

Nice try, but hoof is right. Nitrogen obeys the same gas laws that every other gas does.

Air is actually 78% nitrogen (major other gases are 21% oxygen and 1% Argon). If it's true that it is actually used in some situations I can only think of two possible reasons:

1) It's readily available as a compressed gas where it's being used (maybe at some work sites?)

2) Nitrogen is inert, unreactive. It would minimize oxidation to interior surfaces. (Can't see how that's really applicable here...)

 

Nitrogen does not eliminate ALL temp related fluctuations in pressure. As nitrogen holds less water vapor than compressed air the temp fluctuations in pressure ARE much less.

That is why Race teams use nitrogen to inflate their tires.

 

For what it's worth, air is 79% Nitrogen!

Thermal conductivity for N2 is indeed lowish. Deep divers that replace N2 by He chillingly know about it!

I sincerely doubt that the effect on tyre pressure is anything but beyond the measurement horizon.

Nice folklore, though.