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Discussion Starter · #1 ·
Last weekend we had an experience that was kind of questionable.

We were attempting to climb up a steep and icy mountain, and got stuck behind a long line of cars who were spinning and couldn't move. The Acadia was doing just fine to that point, but we had to stop because there was no room to keep moving.

After a long wait, it was obvious that we weren't going anywhere, and a large group of us decided to back down and turn around, to get out of the mess.

This required a lot of jockeying of the vehicle, a little spinning of wheels, with the Stabilitrak dashboard indicator flashing on/off a couple of times.

The whole thing took about 20 minutes to finally get free of the congestion and moving again.

During this time, the DIC came on with some message that said "check right rear tire pressure", or something similar.

My wife hit the buttons to see what the tire pressure was reading, and it said 67 psi! Wow, I guess the spinning caused spontaneous air to be added to the tire...

I knew it must be a faulty reading, and basically ignored it, being too stressed out with the situation at hand to do anything else.

We finally got to our destination. After several hours there, and some beer and wine to calm our nerves, we headed home.

At this time, we re-checked the TPMS, and all four tires were in the normal 34 - 35 psi range.

It's been 5 days since, and no further high readings have occurred.

Anyone else see something similar?

I currently view it as an anomaly, and don't plan to do anything about it. Do you think this is the best course? I'm sure the dealer won't be able to fix anything unless he sees the problem.

Thanks.
 

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heat will expand the air in a tire and give you that kind of reading - that's why you should not fill a tire to the maximum allowed so that there is room for expansion as you dirive. The spinning tire(s) generated a lot of heat in a short amount of time giving you what was probably a correct reading. The same goes the opposite direction with cold as you will loose tire pressure. When ever we have a sub-teen night I generaly will get a warning that my tires are low but after some driving they are back to normal.

Where in Utah are you from? My wife and I lived in Taylorsville and West Jordan from 97 to 2003 before coming to Amarillo.
 

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Discussion Starter · #3 ·
We live in Park City, and I commute to Salt Lake every day for work.

I bet Amarillo is a big change from Utah.

I understand your point about heat:pressure relationship, but I don't really think the tires spun enough to have that much effect.

Someday I'll get out my PV = nrT formula and calculate how much the temp would have to increase to account for the pressure moving from 35 psi to 67 psi. I'll bet it's a lot!
 

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Also at high altitude gas (oxidant) expends, plus heat of spinning tires can give you such a reading on DIC. So better to use a nitrogen for your tires.
 

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xcskier said:
We live in Park City, and I commute to Salt Lake every day for work.

I bet Amarillo is a big change from Utah.

I understand your point about heat:pressure relationship, but I don't really think the tires spun enough to have that much effect.

Someday I'll get out my PV = nrT formula and calculate how much the temp would have to increase to account for the pressure moving from 35 psi to 67 psi. I'll bet it's a lot!
We spen as much time in Park City as possible - love Adolf's! Weather here is just about the same as there - temp wise - we get a fair amount of snow as well - about 12 inches this season including 2 today.
 

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67 psi - - that is pretty wild and I would agree it's an anomaly. If it was all four tires were reading that high, then I would guess it was a problem with the electronics processing the data from the sensors in the tires. I would not think that all four tires would read exactly the same if heating from spinning were the cause.

If it was just one tire reading that high then maybe there could have been some localized heating of the tire due to the spinning, but that still seems rather far fetched. You might just want to keep an eye on the DIC tire pressures to see if anything else shows up that is unusual.

In my experience, temperature is a bigger factor in the tire pressure changing than is an altitude change. I've seen a 1 or 2 psi change going from sea level to 5000 ft or so.
 

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67psi wow!
Must have just been a freak thing as it came back down.

I had a TPS fail and it triggered an alert every time I drove until it was replaced.

The TPS drives me crazy.
I'm the kind that wants to see all the tires the same (35-40 psi)
My RR must have a very slow leak as it is always 1-2 psi low & I add some air now & then to get it back.

The other week it got down to 38 degrees (burrrr-4 a fla boy), and I got a alert that the RR was low (27psi).
I drove 2 miles to work, opened up the store, and 15 min later took the air tank out to get things straightened out. First I checked the DIC and now the right side tires were up higher than the left side.

The sun was on the RH side and had already brought the psi's up. Only after a 10 mile trip later in the morning did things even out enough to add a little air to even them all out.
 

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mine depends on the weather which is understandable, but most of the times the front tires have a lower psi (-3 to 14 psi) ??? rating than the back after a couple of days filling them up with the same amount of air. maybe i should change to Nitrogen......
 

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Nitrogen...are you serious? What a gimick! Sure it doesnt flucuate as much as air, but is it really worth it? Whats next, will they be asking if you want add your own oxygen bar to the center console.
 

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Schram said:
Nitrogen...are you serious? What a gimick! Sure it doesnt flucuate as much as air, but is it really worth it? Whats next, will they be asking if you want add your own oxygen bar to the center console.
I agree. Regular air is already 78% nitrogen! Can't see paying extra for another 22%.
 

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just joking guys, forgot to put the ;D in the end but the oxygen bar in the console would be great...... ;D ;D ;D
 

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Industrial grade nitrogen is fairly dry ... less humidity ... less expansion due to heat.

The same benifit can be had with regular compressed air if a high grade drier is used.

The issue is not with % of nitrogen vs O2 but the amout of H2O vapor in the compressed gas.
Humidity has the greatest effect on increase of pressure due to heating up of a tire.

Still hard to believe 67 psi in a tire
 
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