Tire PSI Increase

Does anyone know what is a safe increase in PSI from a cold start to traveling down the road in warm climates?

Left home the other day...tires aired to 110 PSI, TPMS read 111 exactly on all four tires. Temperature was in the low 50's. later that afternoon TPMS read 130 PSI, tire temps between 85-90 with outside ambient temperature in the 80's.

Is a 20lb increase in PSI an acceptable margin?

Steve, first thanks for a fun rally. From what I can find on line, there should be a 1# increase with each 10° rise in temperature. Sounds like the increase you are getting is excessive. Can not find a reason why maybe checking with the manufacturer would resolve the question.
Bruce

The Rally was our pleasure...we had a great time! I will post a "debrief" and some pictures tomorrow. I have read the 1 lb per 10 degree thing too but I have a hard time accepting that simply because my tires can easily vary 10-15 degrees just from sunny vs shady side of the rig. The PSI usually changes much more than 1 lb per 10 degrees while going down the road! It's a mystery? Sometimes I think we get to much information from all the gagets! It would be so much easier "not to know"


Best Wishes!

After having a TPMS I realized what a big change there is in preasure when moving down the road. I have had tires go as high as 125# to 130# and temps go to 115*. I am not as excited about it as I used to get. I lost the tread on a G-614RTS in Delaware at 114# and 114* in July when the outside temp was above 100* but I think that was a defective tire, I sent it back to Goodyear for adjustment, I am waiting to hear from them now. I don't worry about the PSI or the Temp being high as I do being low.

I believe the 1# per 10 degrees ambient temperature has to do with cold pressure. So at 50 degrees, you see 108#. As temps come up to 70, you see 110# without changing anything. Beyond ambient temps, sunshine on the tire and heat from the road surface, as well as heat generated internally within the tires while driving, all contribute to the temp and PSI.

PSI on my tires also goes up quite a bit. 5-10 PSI just from the sun shining on one side of the rig isn't unusual. Once on the road, at 55MPH, pressure quickly increases to the low 120s. At 100 degrees outside, driving on the hot highway, pressure is between 125 and 132.

Based on the info provided during the tire seminar at the Goshen Rally, if you're going faster than 55, I would expect higher pressure readings because the tire is generating more heat internally.

I'm not a tire expert, so I can't tell you authoritatively that these increases are safe, but they seem consistent with information presented at the rally.

I agree with Dan. I run 100 psi in my G614's and I see very similar increases in temperature to what you describe. On a hot sunny day the pressures get up to around 118-120 and temps in the 90 degree range. Road surface and material are a factor as well. New blacktop is a real eye opener.

At a tire seminar given by a retired tire engineer from GoodYear I asked the question about the increase in temperature like the question you are asking. His response was the increase in temperature is taken into consideration when the tire is engineered and manufactured. He said what would be of concern would be if one of the tires is way out of line with the others, for example they are all all at 125 except for one that is 145. The one at 145 would warrant further investigation.