Saw this question on temperature and pressure increase on a new set of Goodyear Endurance tires.
"Took our first trip with the new Goodyear Endurance tires.
Trailer rode great, better than the old tires.
So, on this first outing I closely monitored the TPMS to see if there
were any differences in the readings I had with the old tires.
Obviously, the first difference was the starting "cold" tire pressure. (65 psi vs the old 50 psi)
The first thing I noticed was how quickly the tire pressure increased once we got on the road.
87 degree day, 60-63 mph, tire pressure on sun load side got to 75psi
(73 - 74 psi on shaded side). Tire temp got to 96 - 97 degrees (99
degrees on one tire briefly).
This compares to the average 5 - 8 psi increase I experienced on a typical trip with the old tires.
This brings me to my question.
Is a 10 - 12 psi increase in pressure considered acceptable? If so, what should I set the high pressure alert at on my TPMS?"
The temperature and pressure changes are reasonable for most 14" - 16" RV tires, especially trailer applications, but I will focus on your question.
Not sure if your "test" is "scientifically" sound -- You were comparing two different tires (LR-C vs. LR-D) and a new tire vs. old used tire.
New tires will always run hotter than old tires.
With nominally dry air the pressure will increase by about 2% for each +10F. One other related item is that aftermarket external TPMS are not reporting the temperature of the hottest areas of the tire which is internal to the structure. Also while it may not seem reasonable, it has been demonstrated that the temperature of the air inside a tire is not uniform. It is also known that the metal body of valve stems and the metal body of the sensor will be cooled as it whips around in outside ambient air which will result in a lower reading.
In all probability your tire is actually 20 F to 30 F hotter than the TPMS is reporting, but this is within the expected design limits considered by tire engineers.
tires do run hotter than old for a couple reasons. Extra stress as
initial cross-link chemical bonds are broken as tire is "broken in." This
takes about 100 miles. New tires have deeper tread depth, which will
also make a tire run hotter, which means more pressure growth. Your GYE
have extra components (mass) in the tread. Read the sidewall and I
believe you will see Nylon cap plies in the tread which were not in the
old GYM tires. This is another contributor to more heat.
question on pressure increase setting for TPMS. As I covered in my blog
post on TPMS settings I figure that +25% from baseline is a reasonable
number, but obviously the pressure you select for your baseline may
affect the top number.
Bottom line. Your numbers look normal and acceptable.