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Hello eveyone, this is my first post. 2008 xterra, I live in tampa, Fl, just got new tires, exact match to manufactures recommendation. New tire not nitrogen. They said they replaced the gaskets between the tps's and rim. Door panel says 35psi. 2 tires are leaking down to 30psi. Original tps's. Some tire shops say 3-5lbs is ok. So anyone out there in FLORIDA run there tires at 30psi? Will this cause unusual tire wear? This has become a pain. Im only seeking input from central and southern floridians due to climate north of here can cause flucuations. Unless you are a professional and 100% sure of the information. Thanks for your input
 

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I don't understand why this seems to be so complicated. Weather will not make tires quickly loose pressure and stay there. Yes when it is cold, the moisture in the air of the tire contracts and results in lower pressure. So either you have a leak or you don't. Take it back to the place that put the tires on and have them check. Or get you some soapy water and a spray bottle.

Phd in Florida Tires and Climate reactions for body on frame SUVs
 

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I don't understand why this seems to be so complicated. Weather will not make tires quickly loose pressure and stay there. Yes when it is cold, the moisture in the air of the tire contracts and results in lower pressure. So either you have a leak or you don't. Take it back to the place that put the tires on and have them check. Or get you some soapy water and a spray bottle.

Phd in Florida Tires and Climate reactions for body on frame SUVs
satown, where'd ya get your PHD from? Clown College?! Just shittin ya but ... Ideal gas law PV=NRT therefore P=NRT/V and Pressure of a gas (oxygen or nitrogen or a mix of both - air) in a given Volume (a tire) is directly related to temperature. As temperature goes up pressure goes up, temp goes down pressure goes down. Nothing to do with water in the tire. As a matter of fact water is incompressible which is why you get hydro-lock in cylinders that ingest water. It can't be compressed (contract). My PHD is, in fact, from Clown College and I have the big shoes to prove it.
 

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satown, where'd ya get your PHD from? Clown College?! Just shittin ya but ... Ideal gas law PV=NRT therefore P=NRT/V and Pressure of a gas (oxygen or nitrogen or a mix of both - air) in a given Volume (a tire) is directly related to temperature. As temperature goes up pressure goes up, temp goes down pressure goes down. Nothing to do with water in the tire. As a matter of fact water is incompressible which is why you get hydro-lock in cylinders that ingest water. It can't be compressed (contract). My PHD is, in fact, from Clown College and I have the big shoes to prove it.
If we're getting technical, liquid water can be compressed - just not very much or very easily. Water vapour on the other hand can be easily compressed.

Both the air and water vapour will change pressure when the temperature changes, but not by much. A 5°C temperature drop (say from 300K to 295K) will only result in a 1.7% drop in pressure.
 

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Good points for sure.
The fact remains the pressure drop should have been rather equal in each of the OP's tires.

If he has developed a 14% reduction in pressure in two of his four tires, something is awry.
 

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The way I was understanding it was he was thinking his pressure reduction was to weather. But I read as his tires started at 35 and then went to 30 and stayed there. Part of what I was trying to say was that your tires wouldn't loose 5 psi because of cold weather and then stay there even if it warmed up.
 

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What I have found to be common is that tire shops almost never clean the sealing surface inside the wheel and never brush once around a new tire to remove loose rubber that could interfere with the seal. I had a tire on my X that dropped to nearly flat. I pumped it back up, and this didn't happen again for over a month. This time, I put a mark on the wheel at the bottom edge, then parked with that mark down next time. Sure 'nuff, tire went down. It finally occurred to me that if the area that has the most dirt or corrosion is on the downside of the tire when parked, a near-leak becomes a leak and the tire goes down. I pulled that tire off, and found a really ugly bit of corrosion right by my mark. Cleaned it up and have not had another leak.
 
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