This thread may have drifted a bit so I will try and answer the Temperature question here then start a different thread on speed.
Tire temperature is important but the problem is in learning what the actual temperature is. The average temperature is not a good indicator and that is about all you can get by reading the C
emperature. While many seem to believe that their external TPM is giving them a reading of the CAT
, I can tell you that the TPM will always read 10 to 50F cooler than the CAT and that the CAT is always cooler than the hottest location in the tire.
I read that many TPMS have set as the high temp warning point at about 158F. That is all well and good if you are measuring the actual CAT but I do not know how an external TPM will sense that temperature especially if it is on a metal stem or at the end of an extension hose.
I would always be more concerned about the pressure measurement as that is not going to be affected by cooling of the valve stem or extension hose. We know that for our purposes pressure does follow the "Ideal Gas Law
" and it doesn't matter if you use air or Nitrogen the results are essentially the same unless you are measuring your pressure to the 0.1 psi.
So knowing that tire pressure will change by about 2% for each change of 10F in temperature of CAT we can get a reasonable estimate of the CAT and will note that out TPM is showing a lower temperature change than indicated by the pressure change.
I would not use the temperature reading from a TPM to set tire pressure. If I got a high temperature reading but the pressure reading was reasonable I would suspect a mechanical problem such as bearing or brake issue.
A motorhome properly loaded with the inflation set based on actual measured load on the tire and consulting the load Inflation tables will not result in an over-heated tire. NOTE
Trailers should use different method to set pressure due to the Interply Shear
issue of trailer axle alignment and should set the cold inflation to the tire sidewall pressure.
If the above isn't enough detail for you you can visit my blog where I have 20 posts that have Temperature as part of the topic.