Forum Discussion
CapriRacer
Nov 30, 2019Explorer II
Octaneforce wrote:2bzy2c wrote:Captain_Happy wrote:
Something else to consider is inflating your tire with Nitrogen instead of pain air. Nitrogen doesn't heat up like plain air does. You stated that you F53 handles pretty good with PSI at 80 PSI when you start out, but as your tires heat up the handling changes. I've owned 2 F53 and they both handled badly.
Bzzzzzt WRONG!
There is virtually no difference between N2, O2, Air and Co2 thermal expansion rates.
"I'll take Thermal Expansion for $100 Alex."
Geek speak on the subject -->
Ideal Gas Law: PV = nRT
This formula is the "Ideal Gas Law Formula." Although there is no such thing as an ideal gas the formula is pretty accurate for N2, CO2, and oxygen as we assume that the gas molecules are point masses and the collisions of the molecules are totally elastic. (A completely elastic collision means that the energy of the molecules before a collision equals the energy of the molecules after a collision, or, to put it another way, there is no attraction among the molecules.) The formula becomes less accurate as the gas becomes very compressed and as the temperature decreases but here "very compressed" pressures are well above even the highest tire pressures and "decreased temperatures" are extremely cold, too cold for tires. There are some correction factors for both of these factors for each gas to convert it to a Real Gas Law Formula, but the Ideal Gas Law is a good estimation of the way N2, CO2 and "air" should react through temperature changes. What does all this mean? It simply means that "air", nitrogen vapor, and CO2 vapor should all react pretty much the same within normal tire pressures (0-120 PSI) and temperatures.
In the hvac business we use nitrogen for leak down tests under the assumption that it doesn't fluctuate in pressure like compressed air will. However we use pressure way beyond that of a tire (500-600psi). I guess this is within the theory you provided.
Why do race car drivers bother to use nitrogen in their tires? Is it a myth?
If your HVAC assumes that nitrogen doesn't fluctuate like compressed air, then that assumption is wrong. Nitrogen behaves almost exactly like air. After all, air is 78% N2.
Why are you using nitrogen in HVAC? Because it is easy to get in high pressure bottles. The same reason racers use N2. They use those bottles to power their impact guns, so it's readily available.
Plus nitrogen isn't Freon, which is expensive.
Oh, people will say that they use N2 because it is dry (no water vapor) or that N2 doesn't vary due to temperature, but they have that wrong. It's such a common mistake that it's hard to convince people otherwise.
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