Maybe it's normal...

[Glenn the fifth]

Hello all. Made my first trip with my G rated/110 PSI tires this past weekend and something kind of surprised me. When I left the house it was about 65 degrees and each tire was at 107 to 108 as indicated by my TST 507. I had originally set them at 105 about a week ago, but that morning it was pretty chilly (around 50 degrees). So, I start down the road and the tires heat up to 72 to 74 degrees and I thought that was good because my past E rated tires would heat up a little more. What surprised me was the pressure increase. Each tire got up to about 122 or 123 during the hour and a half drive and the tire temp never got above about 74. So...normal? I am asking now because this summer I will be traveling a lot further and the temps will be in the 90s. I currently have my high pressure warning set at 125 psi. Thanks, Glenn

[rohrmann]

That's just about what mine does. Don't remember what my high pressure setting is, but I did set the low pressure setting to 100 psi. I think I've seen 130 degrees, but still don't worry, and that's doing 68-70 mph on a warm day. I think I left the temp setting at the default that the monitor came with. I have had the morning temps close to freezing and the pressure at maybe 99 psi, so the alarm goes off, but within minutes of moving, the pressure is at or over 100 psi.

[DQDick]

My TST manual said to set the high pressure at 25% above what you run them at. Since I run mine 108-110# I have my high limit set at 135#. Towing in Arizona at 105 I've seen the door side (my heavier side) be in the sun and the pressure rise to 129#. I would increase your high limit and drive on unconcerned. Remember there are a lot more belts involved in these tires so there is some heat and as a result pressure buildup.

[Glenn the fifth]

Thanks Dick and Bob! I knew it was not really a concern, just kind of surprised me a bit that they would go up 15 psi when it was only about 65 degrees outside and the tire temps were in the low 70s.

[rohrmann]

I know the pressure sensing is pretty accurate, but not real sure how close the temps are. The biggest thing I watch for is pressure balance, just gives me an idea how any one tire is doing compared to the others. The temps are interesting, and I really don't worry about the high temp, as I believe I read that anything under 150 degrees is probably OK, which I might expect to see on a real hot desert day, And I am doing my best to avoid those situations.

[rohrmann]

I knew I would find it. The high temperature default setting is 157 degrees on the TST sensor system. This is copied from the Quick setup manual:

4. To set parameters, press and hold MODE until the monitor beeps. Press MODE twice; you should see a C or an F. Choose F for Fahrenheit. {The temperature default on the system is 157° F, which is the Michelin standard; tires typically fail between 180° F and 200° F.}

[Glenn the fifth]

Thanks again Bob. I am not too worried about temperature too much either as long as all the tires stay about the same temp. -Glenn