Need help with pressurized air

[CapriRacer]

Conduction trumps convection.

The only reason I even mentioned convection is because the tire isn't significantly heating the surrounding air because of that convection.

You talk of percentage change in tire pressure, yet the tire pressure due to excess water, is an absolute pressure = ppH₂O, independent of the initial tire pressure.

Indeed. That was the part that I was missing! And in particular, how that occurred.

That is why the temperature of a tractor tire running 12 psi, is more effected than a truck tire that is running 100 psi.

Interestingly, the way tire load tables are set up would result in that 10% (or so) pressure for both the 12 psi tractor tire (1.2 psi buildup) and for the 100 psi truck tire (10 psi buildup) and like you said the tractor tire would be much more affected by that water vapor. The point of my query was to understand how large the effect of "evaporating" water was having on passenger car tires, compared to racing tires and whether it mattered. Turn out it does, just like people's real-world experience.

The pavement cannot rise much more than 35°C above air temperature, because then, black body radiation to the environment will remove heat at the same rate that the sun can deliver energy to the pavement. At the same time, the pavement must be significantly hotter than the air and environment, as it must radiate heat at the rate it is delivered by the sunlight.

So that sort of lines up with what Google's AI reported.

Your reference confirms the following quote, but it disagrees with the lower internal air temperature that you claim. I have not yet found a peer reviewed reference.
"On a hot summer day in Australia, where air temperatures can reach 40°C, and road surfaces exceed 60°C, the air temperature inside a tire can easily reach 70°C to 90°C or higher."

That quote doesn't quite line up with my experience. I could believe a 65°C AVERAGE air chamber temperature - HOWEVER, we know that trying to measure the air chamber temperature is problematic as the temperature actually varies inside the tire depending on where you measure it. I wonder if that is where those numbers come from. I can easily see certain parts of the tire/wheel system getting that hot, but there is a subtlety to stating the internal air temperature that doesn't appear in that quote.

 

[Baluncore]

HOWEVER, we know that trying to measure the air chamber temperature is problematic as the temperature actually varies inside the tire depending on where you measure it.

There will be positional variation in the temperature of the compound, but the air within the chamber should be well mixed. Some TPMS measure the pressure and the temperature of the internal air. I have seen references to air temperature sensors placed inside the wheel for experimental monitoring purposes.

 

[CapriRacer]

There will be positional variation in the temperature of the compound, but the air within the chamber should be well mixed. Some TPMS measure the pressure and the temperature of the internal air. I have seen references to air temperature sensors placed inside the wheel for experimental monitoring purposes.

I think that is fundamentally the problem with measuring the temperature within the air chamber. The probes are usually placed ON something, not suspended in the air.