What is this stuff on my new truck?

The answer is gonna be “You wanna buy this truck or you wanna pretend you’re Bill Nye the Science Guy?” until supply improves to meet demand.

 

One of the best observations this year! Someone needs to ask a dealership this question and tell us the answer!

 

The ideal gas law is for an ideal gas, neither nitrogen nor air is an ideal gas. Pvnrt can be used in a crude sense but is only exactly applicable to an ideal gas.

 

The machine has a purge cycle.

 

Agreed but as you state the ideal gas law can be a proxy to predict the behavior of a non-ideal gas. Depending which compound is being observed (N3, O2, etc), the ideal gas law can give you a directional estimate. When using is for a mixture such as air, it really depends on the mixture but even still a mixture will expand and contract due to temperature changes somewhat predictably if all other variables are held constant.
In the end, it a tire and compressed air is just fine for us mere mortals and the DD we do.

 

Never knew that, seems excessive for passenger vehicles.

 

Yeah; I'm not a believer.
Here's one that can run up to 5 purge cycles...my question then becomes, "why is 1 purge cycle not sufficient"?
https://autoprodistributing.com/product/nitrogen-tire-inflator-model-q100/

 

Don’t tell them that, then they’ll charge even more! Haha

 

Yes, however, to the point of air vs "pure" nitrogen neither are an ideal gas and so you cannot claim the ideal gas law states they will act the same since neither is an ideal gas.

 

ok, you got me curious , per my statement, an ideal gas in a fixed volume container at 35.0 psi when gradually cooled from 100 F (hot tire after long drive) to 50 F will drop to 31.87 psi (35 * (459+50)/(459+100) or 31.9 psi on a typical tire gauge.

@Firn , Please support your statement with answers for Dry Air and Dry Nitrogen for same temperature change.

 

Support my statement that Air and Nitrogen are not ideal gasses? Running the math doesn't prove or disprove my statement that air and nitrogen are not ideal gasses, although a list of gas constants does. You can find a listing here if you would like - https://www.engineeringtoolbox.com/...=In the imperial system the,= 0.167226 J/kg K.


Interesting that make an effort to specifically state DRY air and that sure leads me to believe you are playing games here. It is especially interesting considering that one of the claimed benefits of a nitrogen fill is the nitrogen is in fact dry, while air from an air compressor is decidedly NOT dry. Another reason that air in tires is NOT "ideal".

 

Not trolling, but I know air properties will change at different moisture content and wanted to remove an unknown variable as most gas tables assume dry gas plus wanted to keep the example close to a simple textbook problem that would be easy to generate numbers.

The only reason we're having this conversation is because there are websites out there saying "Nitrogen is good because it is an inert gas and does not expand or contract" This is easily disproved by the Ideal Gas Law even if the gases in question do not exactly follow the ideal gas law. Much of engineering is based on theories and scientific principles that are acknowledged as not being exact but good enough given other assumptions and unknowns used in the analysis. If someone want to say the Nitrogen in a commercial N2 cylinder in not pure N2, yeah, probably true, but we have to assume it is otherwise we got nowhere to start and for a 3 digit precision answer, it's probably real close. If you want a 6 digit precision answer, then yes, by all means get the gas tested before you run the numbers. If someone instead wants to say a table of gas constant proves that gases do not follow the ideal gas law, then I'll stand aside and let others comment on what the "R" in the equation PV = nRT means.

For those who are interested in the original question if air vs nitrogen will result in different pressure as the tire heats up, here is the math using the value from Table graciously in the above link, As noted, this uses the values for dry air and dry nitrogen. I'll let the reader reach their own conclusion.
PS: As a swag for humid air, Vapor pressure for pure water is ~0.8 psi at 100 F, so if we want to approximate air with high moisture content then at most the values for high humidity air would be something less than 0.8 psi higher than the N2 numbers. If someone has an engineering SW pack that will do math for say 20% RH air, I'd be interested in the answer as I have long forgotten the equation.

And all of this is probably a moot point because this is a Tacoma site after all and we should all be out on weekends deflating our tire for off road adventures and refilling them with our portable air compressors thereby diluting whatever N2 there was place in by the dealer or tire store. I for one is not going out to buy a Powertank setup just so I can keep dry N2 in my tires.