Tire pressure question

Mandalay Parr wrote:
Set your cold pressure in the morning and don't futz with it during the day, week or month.
I set mine once a year. I'm all over the country and never re-adjust the pressure.
I do monitor the pressure in case I have a leak.

I don't futz with my car tires either.

I think there can be exceptions to this. For those of us that are Snowbirds and leave the north in the coldest months of the year (December, January), the temperature can change from 0 degrees in the North to 80 degrees or more in the deep South.

I for one, have had to adjust my tire pressure as my alarm warned me of excessive pressure.

Once read in a topic , that tires are tested to can stand a pressure of 2 to 3 times the Pressure behind AT, is officially called reference-pressure , but will use AT-pressure further on..

Also read in a PDF of Semperit/Continental, that when standing still a cold pressure of 1.4 times the AT-pressure gives 2 times the maximum load when standing still.
This means that you could even give the tire a cold pressure of that 1,4 times the AT, wich is for your AT 65 psi tires, a cold pressure of 91 psi .

Asume you would fill this pressure at 32 degr F, so freesing point of water, and temp in tire rises to 212 degr F , so boiling point of water, the pressure would rise to 130 psi , wich is 2 times the AT-pressure of 65 psi, and tires are tested to can stand this pressure .

So dont worry about getting to high pressure, tires and valves can stand this pressure.

I wont say that you must fill your tires to that 91 psi , but if needed, 80 psi at 65-68 degr F would not be a problem.

Will give a list of pressure for temperature, and use it like this.
See first what the ambiënt temp is at the moment you measure your cold pressure ( = when inside tire temp = outside tire temp).
Then look in the list at that temp , for your measured pressure.
Then see what it would be in that row what it would be at 65/68 degr F, and compare that to the advice pressure.

Mind that if your tires are already damaged by overheating of the rubber by using to low pressure for the load and speed , the tires will blow sooner when filled with higher pressure, so only do this to new tires from the beginning , to prefent this damage .

I can help you with determining a save pressure, but need more info .

Do you worry about your truck tires blowing with temp and elevation changes? What worries me about trailer tires is poor quality.

donn0128 wrote:
Every tire mfg in the world states MAXIMUM COLD tire pressure. Set it where you are and go. There is always allowance for margain.

Bet that recommendation is at STP (remember this from chem class? Standard Temp and Pressure?), which is probably 70 or 72F. Were it close to freezing, I sure wouldn't worry if my E tires were at 76-78 psi, so long as they were =all= the same. At 70-72F, I'd be willing to bet they'd be right at 80. :)

Lyle

jstaffon wrote:

donn0128 wrote:
Every tire mfg in the world states MAXIMUM COLD tire pressure. Set it where you are and go. There is always allowance for margain.

Thanks bud...makes sense.

We're heading to Oregon in a couple weeks. Destination is Portland. Any suggestions on RV Parks? Wanted to stay a night or two somewhere in Oregon between Boise and Portland.

Which side of Portland?
On the east side you have really two choices.
Portland/Fairview on Sandy Blvd easy off I84. Or sandy riverfront in Troutdale both are decent parks, but you will hear trains.
South or west of town, Champoeg state park is a good choice.
As for coming this way? How big a hurry are you? Fast of course is I84. Night one of the parks on the east end of the gorge would be OK.
Slow come over on 26 and visit several parks, bates, east of John Day, or there is a nice state park about 7 miles west of John Day right on the river.

Unless you have tire-by-tire weights, your trailer axle weights aren't of much use for determining inflation pressures. Our rig, loaded for full-timing, is a little over 1,000 lbs. heavier on one side than the other. That would mean a 500 lb. difference in load for those two tires compared to the other side. We do happen to have recent wheel-by-wheel weights (Escapees SmartWeigh program), so we inflate - per tables - to the maximum load for the wheel with the most weight. Since the load range G tires on the rig have a large capacity margin compared to the weight on the tires, it ends up being 10 PSI below the maximum inflation pressure listed on the sidewall.

We fall in the middle of the approaches described above. Unless we are "homesteading" (like we are for two months right now to be near a new grandbaby) we tend to move at least every two weeks. I check the cold inflation pressures on all the vehicles (fiver, truck and wife's "chase car") late the evening before we roll or early the morning of travel. The TMPS (tire pressure management system) is set for the nominal inflation pressures and has built-in limits for over- and under-inflation at which it will alarm (high temp alarms, as well). As said above, I don't mess with pressures in between unless the TPMS tells me there's something wrong.

Rob

Mandalay Parr wrote:
Set your cold pressure in the morning and don't futz with it during the day, week or month.
I set mine once a year. I'm all over the country and never re-adjust the pressure.
I do monitor the pressure in case I have a leak.

I don't futz with my car tires either.

That makes me feel better. The cold mornings (45 degrees) indicate 62 psi on all of my tires. They all can't be leaking at the same rate. They were all 65 psi earlier this year so it must be temperature related.

donn0128 wrote:
Every tire mfg in the world states MAXIMUM COLD tire pressure. Set it where you are and go. There is always allowance for margain.

Thanks bud...makes sense.

We're heading to Oregon in a couple weeks. Destination is Portland. Any suggestions on RV Parks? Wanted to stay a night or two somewhere in Oregon between Boise and Portland.

Set your cold pressure in the morning and don't futz with it during the day, week or month.
I set mine once a year. I'm all over the country and never re-adjust the pressure.
I do monitor the pressure in case I have a leak.

I don't futz with my car tires either.

Every tire mfg in the world states MAXIMUM COLD tire pressure. Set it where you are and go. There is always allowance for margain.