Towing 5'er, mountain pressures

[jdkinzenbaw]

Guys,

As a resident flat-lander from the fine state of Iowa, we travel west at least once a year to Colorado. This year I'll be towing my 5'er Toyhauler.

When I'm pulling my toyhauler, I always try to have maximum rated pressure in the truck tires. In the case of my Nitto's, that's 80psi.

I know from experience that tire pressure increases up in the mountains with altitude. Starting off at 600ft of altitude with 80psi max pressure, and climbing over 12,000-ft mountain passes, should I back my pressure off a little before I start up the grade?

Has anyone had any experience with pressure changes going over mountain passes loaded heavy with that drastic of altitude change? I'm not even sure how much fluctuation to expect at that kind of load.

Thanks ahead,
Jon

[2006PSDSD]

Never really though of that, but it makes perfect sense. If I were you, just make sure you're at 80psi when you get to the Denver area, then you should be able to go anywhere you want. Let us know if the pressure changed, and make sure you check the tires when they're cold, so we get an accurate number

[jdkinzenbaw]

Okay, I'll try to remember to do that. We won't be going out there until August probably, but I'm actually thinking of swapping out the tires on the 5'er before then anyway. It came with some cheapo Chinese brand tires that might be fine running 65mph down I-80 in Illinois and Iowa, but I don't trust them to major altitude changes and the likely stop-and-go stress of Denver traffic as we pass through.

Problem is, when we get to Denver at 5,000 feet, we still have well over a mile up to get over some of those mountain passes.

I did invest in a good TPMS system (TST) that I'll be installing shortly. That should give me some good latitude.

Anyone else have any experience with this? I don't like being the first. I'd rather have you guys get the flats, and me learn from it. LOL...

[2006PSDSD]

Where are you going in CO? I think you may be the first one to ever think about tire pressures and elevation changes

Denver traffic shouldn't be bad between 9am and 2pm, FYI

[jdkinzenbaw]

We're headed back to the Gunnison National Forest area to do some ATV riding. We take a huge group of close friends and family every year. This will be year #5.

In years past I haven't worried, because my tire pressure is usually 10 or 15 pounds (at least) under max pressure rating. Now that I'm bumping up against max pressure rating (due to the full load of my 5-er hitch), I want to make sure I'm being cautious.

The first year we went out, I emptied a 1 gallon gas can into my quad while we were still at 10,000 feet. Then I drove home, and back at 600-feet altitude, the gas can had crushed like a pop can, because it was one of those stupid new sealed cans without a vent. Now I drill vent holes in all my fuel containers and only plug them if absolutely necessary.

So, all that to say, altitude makes a huge difference on pressure in sealed containers and sealed tires. Pretty incredible.

If I dig up the picture of that crushed gas jug, I'll post it just to show you. Pretty incredible.

[2006PSDSD]

I have the same issue when taking my belly boat to the mountains. I only fill them about 70% and they are full by the time I get where I'm fishing

[nitrogen]

fill them to max at home and don't worry about it, the drop in atmospheric pressure isn't going to be enough to increase the pressure differential significantly. the gas can that is sealed at high altitude and then take to lower level is actually a bad example, they are designed to have higher pressure inside than outside.it will only take a few oz. higher pressure on the outside to collapse that can. eg, fill that gas can with gas that is say 90+f, seal it up and cool it off to 30f and it will collapse as much as the liquid will allow too.

[TMAG6.0]

Thats some good thinking. When I bought my trailer it came with tires that could not handle the trailer fully loaded. I had 2 flats in the heat of the day on the way home. On the second one I had no spare. It was quite the ordeal, and hard to find 4 E rated trailer tires on Sunday afternoon. I never thought to check the load capacity of the factory tires.....When added up they were way under GVWR. Learned the hard way how important the correct tires are.

[jdkinzenbaw]

Originally Posted by TMAG6.0

Thats some good thinking. When I bought my trailer it came with tires that could not handle the trailer fully loaded. I had 2 flats in the heat of the day on the way home. On the second one I had no spare. It was quite the ordeal, and hard to find 4 E rated trailer tires on Sunday afternoon. I never thought to check the load capacity of the factory tires.....When added up they were way under GVWR. Learned the hard way how important the correct tires are.

WOW... so your trailer came with tires that weren't rated for the load? Seems like that's just a lawsuit waiting to happen. Not that I'm encouraging it, but if your trailer mfr didn't put the right tires on it to begin with, that's negligence.