Nitrogen inflation to 125psi

[TedS]

NoPeeking Mike, I'm with you. Never had a tire problem with moisture in compressed air. Had ice form on pneumatic mining equipment exhaust.

[Schiefswret]

So, got our Solitude 310GK a few months ago and the tires are supposed to be at 125psi cold. They are also currently filled with nitrogen. They are about 15psi low right now, but I cannot find anyone in the San Diego area that can top them off with nitrogen. I can get them to 125psi with air and am not a rigid advocate of nitrogen, but would like to keep them inflated with nitrogen if possible. Have called RV dealers, semitruck shops, and tire stores with no luck. Anyone know of a place in the San Diego area than can provide nitrogen to 125psi? Thanks.

the air we breathe contains 78 percent nitrogen. Marketing, go figure. Just take it up to the desired psi and go on living.

[AlexPeterson]

When tires are mounted, there is a bunch of watery slop used to lube the beads. This moisture likely overwhelms any moisture put in by air from a compressor.

[Country Campers]

I thought the reason for nitrogen filled tires was for pressure stabilization, less swings when change in temperature and elevation.

Brian

[Scott'n'Wendy]

I thought the reason for nitrogen filled tires was for pressure stabilization, less swings when change in temperature and elevation.

Brian

I thought it was for making money....

[TedS]

All gases behave the same with temperature and pressure whether mixed as air or alone as Nitrogen or Oxygen or Hydrogen. Nitrogen's special property is that it is inert, non-reactive.

[AlexPeterson]

I thought the reason for nitrogen filled tires was for pressure stabilization, less swings when change in temperature and elevation.

Brian

Regarding pressure changes due to temperature - it won't matter what gas mixture as gases follow Boyle's law, often referred to as the Ideal Gas law. The pressure will vary linearly with the temperature as expressed in absolute terms (absolute temperature in F, add 460, Celsius add 273). There would be a small additional drop in pressure due to water condensation as the temperature drops below the dewpoint, but it would only be a few percent I believe. Tires filled to 80psi at 40 degrees F would measure about 12% higher at 100F, or about 90psi. At 0F, they would measure about 74psi.

Regarding altitude changes, higher elevation will indicate a higher pressure. For example, at 11,000' above sea level, the atmospheric pressure is about 9psi. Tires inflated to 80psi at sea level would read about 14.7-9 = 6psi higher, assuming that the temperatures are equal.

Edit:
TedS you beat me to it - I got sidetracked as I was replying!

[Yoda]

Regarding pressure changes due to temperature - it won't matter what gas mixture as gases follow Boyle's law, often referred to as the Ideal Gas law. The pressure will vary linearly with the temperature as expressed in absolute terms (absolute temperature in F, add 460, Celsius add 273). There would be a small additional drop in pressure due to water condensation as the temperature drops below the dewpoint, but it would only be a few percent I believe. Tires filled to 80psi at 40 degrees F would measure about 12% higher at 100F, or about 90psi. At 0F, they would measure about 74psi.

Regarding altitude changes, higher elevation will indicate a higher pressure. For example, at 11,000' above sea level, the atmospheric pressure is about 9psi. Tires inflated to 80psi at sea level would read about 14.7-9 = 6psi higher, assuming that the temperatures are equal.

Edit:
TedS you beat me to it - I got sidetracked as I was replying!

TedS

You both made my head explode this morning making me remember all of this from my college classes (civil engineering) How do you remember all of this? Of course I did not worry about gas so much building bridges and roads, except for confined spaces, welding, and eating...well we wont go into eating as methane pollution is a political topic.

And from my reading, to get the real benefit of nitrogen you need to be above 95%or 98%? That would mean pulling a vacuum on the tire first before filling. I know there are ways to do it as auto racing uses it a lot along with other gasses.. I think NASA has a strange blend in the shuttle tires too, and they assemble them in a complete vacuum if I remember correctly.

Thanks for the trip down memory lane and don't forget the most important law that Murphy created

Keith

[Jlawles2]

Yoda Keith, remember the government has an unlimited budget so they can do stupid things like build a pure nitrogen clean room just for assembly of tires. It's just money, they can print more.

[ThePowells]

TedS

You both made my head explode this morning making me remember all of this from my college classes (civil engineering) How do you remember all of this? Of course I did not worry about gas so much building bridges and roads, except for confined spaces, welding, and eating...well we wont go into eating as methane pollution is a political topic.

And from my reading, to get the real benefit of nitrogen you need to be above 95%or 98%? That would mean pulling a vacuum on the tire first before filling. I know there are ways to do it as auto racing uses it a lot along with other gasses.. I think NASA has a strange blend in the shuttle tires too, and they assemble them in a complete vacuum if I remember correctly.

Thanks for the trip down memory lane and don't forget the most important law that Murphy created

Keith

Yoda The biggest use in Nascar is to change tires, and set pressures on pit road. When whoever has the contract now mounts the tires, they use natural air with multiple drying stages. It's just much easier to use than hauling around compressors.

Then there is always another idea, https://www.winekeeper.com/winekeepe...rogen-cylinder You can buy a regulator and have the small cylindder refilled you local gas passer.

[Hvymetal37]

I asked a GD rep or tech, can’t remember which he was, about this at an rv show. He said just fill them with air.