Nitrogen fill in motorhome tires

[Jim and Carol Contratto]

Hi All BAC Members:

Just wondering if anyone has  any information regarding Nitrogen fill in motorhome tires, if anyone has done it, are you satisfied??!!!,   I have  Goodyear G-70's.  

Jim Contratto  
06 Patriot Thunder

[Gerald Farris]

From the research that I have read, there are some benefits to using nitrogen in tires. However the benefits of slightly less air loss and less tire aging and more stable tire pressure with temperture changes are only marginal. Therefore the cost and inconvenience of using nitrogen in your tires is rarely cost effective if you check your tire pressure and maintain it regularly as you should.

Gerald  

[Jeremy Parrett]

Nitrogen molecules are larger than air molecules.  Therefore tires leak more slowly.  Nitrogen filled tires  run much cooler and as heat is a huge factor in tire wear, tires last longer.

[Edward Buker]

Jeremy,

I have never heard that nitrogen filled tires run cooler and for the life of me I cannot rationalize why that would be. I could do a google search but if you already have some insight let us know.

Thanks Ed

[William Brosam]

I dont know about run cooler much, but are more Heat stable yes i agree.

the tires are more predicable at temeperature.

[Lee Welbanks]

Here's a link to the straight scoop on N2 in tires.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=191&affiliate=HM5&s_kwcid=AL!3756!3!55250840053!b!!g!!_cat:tires&ef_id=U7hK7gAABVtQCMzP:20140728044321:s

[Robert Mathis]

It would seem. To me that if Nitrogen molecules are larger that oxygen or co2 molecules, that over time, more O2 and CO2 molecules would leak out or our tires, and eventually, all we would have left would be Nitrogen anyway.

[Karl Welhart]

Clearly there are some benefits to using Nitrogen in MH tires.  However, I (as others on this forum) believe that the benefits do not outweigh the cost, trouble and inconvenience.

[David T. Richelderfer]

The air we breathe, and pump into our tires, is almost 80% N.

[Lee Welbanks]

It would seem. To me that if Nitrogen molecules are larger that oxygen or co2 molecules, that over time, more O2 and CO2 molecules would leak out or our tires, and eventually, all we would have left would be Nitrogen anyway.

Robert, I just love your reasoning, so now I wonder if anybody has actually checked the air coming out of a tire after a couple of years.

[Stan Simpson]

This is the Ford .vs Chevy argument discussion. Just my 2 cents.

Stan

[Joel Weiss]

First of all, I'm not sure where this nitrogen is larger than oxygen stuff comes from.  It sure isn't related to the atomic weight of the molecule since oxygen outweighs nitrogen and is the larger atom.

As for heating, it should be noted that all gases obey the Ideal Gas Law which you might remember from chemistry class.  To remind you what that is, it is:

PV = nRT

What this means is that all gases obey the same laws and essentially heat up at the same rate.  So the claims that nitrogen won't heat up in a rolling tire or will heat significantly less than normal air is simply contrary to science.  As tires heat up the gas in them heats and the pressure in them is subject to the following relationship:

P1T2 = P2T1  which simply means is that as the temperature increases the pressure increases also.  The Ideal Gas Law simply states that all gases will obey the same rules.

I don't care if you want to spend your money filling your tires with nitrogen if it makes you feel better safer, but I thought some people might be interested in the science behind it all.

[Edward Buker]

Thanks Joel, science does add some sanity to what is sometimes folk lore. There are good reasons to keep moisture out of these tires and nitrogen sources do that but water separators on compressors also do that job pretty well. Beyond that, I think other claims are pretty marginal.

Later Ed

[Dick Simonis]

This subject is always interesting.  While O2 has a higher MW than N2, it is also has a smaller "effective" size due it's structure as it's electron cloud is more compact.

Also, what you are dealing with is the permeation rate (or flux) though a membrane..in this case rubber  The effective permeation rate of O2 is ~3-4X that of N2.  So the short answer is yes, N2 will leak down less than air.  However there is a caveat here in that as O2 diffuses through the rubber the quantity of O2 decreases so less permeates and therefore the rate of change decreases with time.

From a practical point of view the change in pressure will be hardly noticeable in the short term.  On the flip side O2 is quite reactive and using nitrogen will, in theory, extend the life of a tire by reducing the adverse affects of oxidation of the rubber compounds if indeed there are any.

Somewhere in my files I have a good paper on this subject I will be happy to dig up if anyone is interested.

[Richard And Babs Ames]

http://www.popularmechanics.com/cars/how-to/repair-questions/4302788 This is from Popular Mechanics