Those with tire pressure monitoring systems..

Found this film about rubber stemms to click your TMPS sensor to , so you can change the stemm every tire chanche and use the same sensor.
They shal have the same testing standards as normal stemms and are probably also available in High pressure .

Rubber stemms to fit TMPS-sensors to

I have the TST Monitor and am very pleased. Have Goodyear 614 @ 110#. We took a trip thru Colorado this fall with temps from 32 to 90 degrees. Had the monitors set at 99# on the low side and 130# on the high. I aired the tires up when the temp was about 65 degrees here in Mo. On the cool morning the monitor would go off because of the alt. and temp. but after about 10 miles temp and pressure would come up to above the bottom limit. As far as the upper I never saw the tires over 121# anywhere.

Remember,the air pressure/temperature will depend on if you are going east or west,morning or afternoon.
The sunny side will be have a higher PSI and temp.
Does that mean if the tires get too hot,that we should turn around and go the other direction? Nahhh,just foolin witcha.

I saw my 15" LRD's increase ~20% while my 16" LRE's are ~10% on the same trailer.

10% is probably a decent number to work from. Here's a link to a good article:

http://www.tirepressuremonitor.com/2014/08/tire-inflation-pressure-and-longer-life-tires/

Then both probably would need higher cold pressure so pressure rising will stay below 10% . For example your 110 psi of car highen up to 120 psi then probably warm will get 120+10% = 132 psi and the trailer from 120 to 130 psi then +10% gives 143 psi.

Yust an example , to find the exact save lowest pressure you should use my made Motorhome or Travel/Trailer tirepressure/calculator.

The Michelins in Europe use 8.5 bar = 123,28 psi converted so J load is mostly given AT-pressure of 125 psi.
A 10 psi higher pressure then AT-pressure is allowed by most Tyre-makers for LT.
But for your J rated and also the H rated , wich can be called Truck-tires even 20 psi above AT is allowed by them.
This gives lesser deflection so lesser bending of the rubber so lesser heatproduction so lower temperature in the tire.
And what its done for is to take care that no part of the rubber of tire reaches a sertain temperature ( My quess 130dgr C/??F) at wich the rubber hardens and damaged by next bendings.
This is probably the cource of your every year a degree higher warm temp. Some parts are getting to hot already and harden wich makes also the heatproduction at same deflection a bit higher.

Your increase from 110 to 123 is a little low in my experience. I usually get to around 128-130. On my trailer I run 120 on my J rated Michelins, these babies get to 136-140 depending on road temp and sun. Been running them for 5 years and each year the average temp has gone up a degree, in a year or two I'll buy new tires, don't want to have too much of an increase in an old carcass.

@ 12th Man Fan

Probably you filled to 80 psi when outside 65 degr F and that hot day was about 90 degrees F. then the "cold"measured pressure would be already higher then 80 psi and say temp rising by riding that 47 degrees I wrote gives 137 degrees to wich probably that 95 psi belongs .

Filled it in in my spreadsheet and filled at 80 psi at 65 degrees gives 84.5psi at 90 degrees and 93 psi at 137 degrees F.

To 95 psi belongs 148 degrees.

so temperature measurement of TMPS is mostly inacurate, but you dont need that . You can calculate the temperature from the cold and warm pressure and the fill temperature outside.

TMPS could be chached in their software that they calculate it from start outside temp and those cold and warm pressure.
Probably more accurate then as its done now.
Pressure measurement of TMPS is mostly pretty accurate but also depends on the quality.

I have seen 95 PSi on a hot day on E rated tires.

Have Goodyear 614 inflated to 110#. They will go up to 121# that is the highest I have seen them.