Razorback
Fayetteville, Arkansas
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If you use a high pressure air pump with tank to air up your tires most of the moisture has been squeezed out before it goes into your tires. That is the reason most air tanks have a drain valve on the bottom to drain the water.
Johnny and Bonnie
1998 Bounder 36'
1998 Saturn
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Dutch_12078
Great Sacandaga Lake, NY
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doc brown wrote:Wheel Estate wrote: do i have this right? air starts out 78% nitrogen; oxygen is smaller and is responsible for 2 psi decease in pressure / month because it escapes....then it looks like in the end I will have pure nitrogen at some point in the future....
Oxygen is a larger molecule than nitrogen (32 molar mass vs 28 molar mass) by a small degree. Therefore nitrogen escapes faster than oxygen. To add to the discussion I put C0-2 in my tires! I check my tires every departure morning and use SmarTire to monitor temp and pressure. Nothing replaces basic care.
You're confusing molecular weight with molecular size. Apples and oranges. Nitrogen concentrators for instance, frequently use a membrane that passes oxygen but not nitrogen.
Dutch
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MountainAir05
New Mexico
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The cost for me on a fill up on my 2200 lbs tank is $10 only for the past 4 years, I have only used maybe 100 lbs, The needle has barley moved. Yes I did have the tank and regulator. Even air is not free, since you do have to have some way to get it into the tire. Lung power does not seem to work for me.
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stevelv
Living on the island
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MountainAir05 wrote:The cost for me on a fill up on my 2200 lbs tank is $10 only for the past 4 years, I have only used maybe 100 lbs, The needle has barley moved. Yes I did have the tank and regulator. Even air is not free, since you do have to have some way to get it into the tire. Lung power does not seem to work for me.
You are probably using more fuel to carry that bottle around than you will ever see in cost savings from running N2.
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Tom N
Sarver, PA/Crystal River, FL/Indiana, PA
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Skip and Norine wrote:
(these aren't my words)
and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage.
This is baloney. If the O2 molecules leaked out you would have 100% N2 which would certainly negate using pure N2 because you would be making your own!
-Tom
retired chemist
Sarver, PA/Crystal River, FL/Indiana, PA · FMCA 335149 · Mystic Knights of the Sea
2005 Suncruiser 38R · W24 chassis, no chassis mods needed · 2003 Honda Civic EX · 2008 Honda Odyssey EX-L
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Dutch_12078
Great Sacandaga Lake, NY
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Tom N wrote:Skip and Norine wrote:
(these aren't my words)
and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage.
This is baloney. If the O2 molecules leaked out you would have 100% N2 which would certainly negate using pure N2 because you would be making your own!
-Tom
retired chemist
Not so, because the loss of O2 and the resulting pressure drop requires adding makeup air containing more O2 from time to time. In fact, even using 100% N2 does not work, because O2 will reverse migrate into the tire, until an equilibrium is reached at about 93% to 95% N2. An often overlooked advantage of N2 use is that it minimizes oxidation of steel tire cords, adding to the tire's life. Trucking companies know this and have used N2 in part because of it for many years. That effect and the slower pressure loss are particularly advantageous to them in trailer tires that may sit for long periods in remote freight yards. Not that our RV's ever sit for long periods of course... 
Dutch
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ArchHoagland
Clovis, CA, USA
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Several people on this post said their tires run cooler with the nitrogen. I'm curious how they know that bit of information.
I check the temp of my tires with an IR gun every time I stop. Seldom do any two tires match in temp, let alone all six. There is always a variance of one to three degrees based on wind, sun and tire pressure. Even the duals right next to each other will vary because of the direction of the exhaust heat in certain wind conditions.
Has anybody done any scientific measuring of temperature under a given set of conditions while using nitrogen? If the temps were lower, what were they lower than?
I've gone across the desert at 115 degrees and I suspect your tires will be very hot even with 20% more nitrogen in them. But I can't prove that.
I don't use nitrogen and have gone as long as two years with little to no air loss in my tires.
Air pressure will vary with temperature and altitude so when you say you have air loss is it based on being measured at the same altitude and temperature?
I did a pressure chart with temps and altitude on a trip 1500 mile trip. Interesting results.
2004 Monaco
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2000 LEXUS RX300 FWD 22MPG 4020 LBS
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frankdamp
Anacortes, WA
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It's a scam for the tire dealers to get money for next to nothing. Do you know they really use nitrogen?
Nitrogen is only useful for heavily loaded, very high speed tires. If the tire gets very hot, gases in the tire compounds can be released into the inflation space and a spontaneous combustion explosion can result if the tire was inflated with air.
If your MH can top 150 mph with a dragging brake and has rectractable wheels, it might help. I don't think many of our friends on this group have business jets!
I personally investigated a spontaneous explosion in a Boeing 727 main landing gear tire. The analysis showed that the explosion caused an instantaneous pressure of almost 12,000 psi before the tire let go. The airplane had taxied for 20 minutes on a hot day in DC and took off with a dragging brake. The tire blew at about 15,000 feet, long after gear-up.
Frank Damp
Anacortes, WA
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