NITROGEN FOR RV TIRES?

[LEAH DRAPER]

Is anyone using or has considered nitrogen for RV tires?  Just had new tires for an auto (not toad) and had nitrogen used.  Seems like a good idea, but wondered about pros and cons of using in RV.  

[Richard And Babs Ames]

Nitrogen has larger molucules and is drier than air. Tires will hold pressure and run cooler is the hype.

My son runs it in his cars but not his motorhome.

Con is you must have an accessable nitrogen source to change tire pressure and the expense as you will not save the cost.

We chose regular air.

[Ken Buck]

Costco fills the tires they sell with nitrogen rich air. The clue is that they'll put a green cap on the stem. They will also check and top off your tires as requested with nitrogen for free. I have a couple of cars (out of 5) with nitrogen. It doesn't seem to keep the tires full anymore that plain air. When I buy new MH tires if they'll fill them w/nitrogen for free, I'll take it. I won't pay extra for it.

Ken

[Bob Adams]

Dry air contains 78.09% nitrogen by volume and just about 21% oxygen. Not much room left for the rest. IMO it's not worth bothering with.

[Gerald Farris]

Nitrogen use in tire inflation was discussed in an earlier thread on this forum.
http://forum.bacrallies.com/m-1245288759/s-0/highlight-nitrogen/#num0

Gerald

[Jeremy Parrett]

Gerald,
 We have nitrogen filled tires on our  Marquis. I have not had to top them up in a year. They run way cooler than they did with air fill.
 Nascar and F1   use Nitrogen. It has to be an improvement over air. Cooler tires last longer?  

[Gerald Farris]

Jeremy,
Comparing tire usage in Nascar or F1 to motorhome usage is like comparing apples and oranges, there is no correlation. Tires on a motorhome will not run any cooler with 100 PSI of nitrogen than they will with 100 PSI of air. Many aircraft also use nitrogen in their tires because of the lack of moisture and oxygen, however the amount of humidity and oxygen that is is compressed air is of negligible concern to an RV

As I stated in an earlier post, the advantage to 100% nitrogen is that the nitrogen molecules are larger than the oxygen molecules that comprise about 20% of air and therefore the tire will leak down slightly less but if you check your tires as you should the very slight difference in leakage rate will not be enough to even detect in most cases. So as I said earlier the cost and trouble involved in inflating RV tires with nitrogen is not cost effective.

Gerald  

[Jeremy Parrett]

I will agree to differ Gerald !

[Bill Sprague]

I'm smiling here.  It is too difficult for me to not joke a little bit!

I can't help but think if the oxygen molecules are smaller, they might leak out first.  So, if you are aiming at 100 psi, you could put in 120 of air.  Then, if you are patient, the oxygen would gradually leak out first and you would end up with around 100 psi of nitrogen.  

[Bill Sprague]

.....I have not had to top them up in a year. .....  

I am on year 8, the second set of tires and I have a pressure monitor system.  I find that I will need to add air once or twice in the winter when air is cold.  As spring and summer roll around the tire pressure varies little.  It seems that the rate of air loss is balanced by the air warming up.  So, even with plain air, I go about a year.  If I didn't have a pressure monitor and I was poking them with a pressure gauge frequently I would probably spill enough air to need service more often.  

[Jeremy Parrett]

Hi Bill,
Brilliant  theory ! I wonder how long it would take for the air to leak out....5 years?  

[Edward Buker]

I have had a couple of inner dual tire failures on my last coach. They were Michelin XRV tires that were never run with low air pressure nor were they ever overloaded. I kept track of air pressure before each travel day and there were no road hazard damage when they failed. I have reliability experience and these fails at 2 years and 5 years of age were non random unexplained events that I persued with Michelin relaibility engineering.  I sent these tires into them for failure analysis. I took close up photographs of the "zipper fails" right after they failed. One observation I made, that could not be explained by the Michelin engineers, is that there seemed to be rust (oxidation) of the steel sidewall cables in the fail region. They wanted to conclude that this oxidation occured after the fail but in the end they could not provide me a scenario as to how that could have occurred given it was dry out and the photograph was taken within several hours of the fail.  

If you have ever pushed a tire schraeder valve and had it mist out some water with the air you can be assured that the air inside the tire is saturated with moisture. It is not uncommon to have air in a tire with a high moisture content depending on the humidity level in the air being compressed. Also if the tire dealer has not drained his tanks properly, has not installed water seperators, and kept those drained properly. I can remember releasing air from the valve on occasion and have moisture evident in the released air from my XRV tires. The air delivery systems at tire dealers and truck stops at best is hit or miss moisture wise.

The final outcome of all this was the hypothesis that the air and moisture slowly migrates through the sidewall, always seeking equilibrium with the outside atmosphere, would condense on the colder steel sidewall cables while the coach sat. This would eventually cause rust. The pits that are formed from the rust are rough and will saw the cables as they go through many expansion and compression cycles. This is only a problem in the RV customer base because trucks that travel most days never have time to accumulate condesate moisture on the steel cables. The heat and motion drive the moisture through the sidewall.

Michelin told me that the interior coating that you see on the inside surface of the tire is an air migration barrier coat and they were looking at possibly thickening that layer to reduce the migration.

The bottom line of all this is you need to use a dry air source, especially if your RV sits over the colder months. I have added a water seperator on my portable compressor and try and top off on dry days. Nitrogen as delivered is a controlled pressure source absent of moisture. If I had doubts about the quality of the air source moisture wise, I would opt for Nitrogen just in RV tires. Interestingly cars do not need to worry about using air saturated with moisture given there are no steel cables in the sidewall to worry about.

Dealing with sidewall tire failure and coach damage repairs from the compression shock wave while on the road is very painfull at best and dangerous at its worst.

My vote regarding Nitrogen use is just under certain conditions. If you could use your coaches air source with a receiver dryer that would also be ideal. You will probably never see this published by the tire manufacturers given the liability issues....Hope this helps.

Later Ed