RV Builder Pumps Tires With Nitrogen--Should You?
It's a heady season for RV manufacturers: The great Recreational Vehicle Industry Association (RVIA) trade show is on in Louisville, and everybody wants to show off their stuff. Enter Dutchmen, the maker of fifth wheels and travel trailers by the same name. What's new in the Wooden Shoe? Nitrogen in your tires.If you remember high school chemistry, you may remember our friend nitrogen, the gas that makes up the majority of earth's atmosphere. While 'plain old air' has been used for years to fill tires, the wrinkle a few years back was to fill tires subjected to a lot of stress with nitrogen. Think race car tires, jet aircraft, etcetera. Why nitrogen?
Plain old "air" molecules are about four times smaller than nitrogen. Because of that, rubber tires slowly "leak" air because the rubber is a bit permeable--the air slowly works its way through the tire pores, if you will. Since the nitrogen molecules are so much bigger, tires tend to lose pressure far more slowly. As a result, the tires run cooler and get better fuel economy. Sounds like "N-inflation" is a shoe in? Hang on, might it lead to a false sense of security? If you don't check your tire pressure as often, will you likewise fail to look your tires over for damage?
Tire permeation isn't the only reducer of tire pressure. Witness a statement from tire maker Michelin, "The existence of several other possible sources of leaks (tire/rim interface, valve, valve/rim interface and the wheel) prevents the guarantee of better pressure maintenance for individuals using nitrogen inflation." The company does not recommend nitrogen inflation, except, "in a high risk environment and/or when the user wants to reduce the consequences of a potential abnormal overheating of the tire-wheel assembly (for example in some aircraft applications)."
Notwithstanding, economics may come into play. A nitrogen tire "fill up," can cost you as much as $10 each. If you're somewhere where nitrogen is unavailable and have a low tire, you can "top off" the tire with ordinary air. But later you'll be advised to have the tire bled out and refilled with nitrogen.
posted by Russ and Tiña De Maris at
10:38 AM
14 Comments:
Nitrogen is a nice "pad" when selling tires. But little or less practical value.
Ordinary air, properly dehumidified, work well and is reliable and cheap.
By
Anonymous, at 2:29 PM
Sounds like a lot of hot air. Just kidding! Seriously, how does one properly dehumidify air for the tire?
By
Anonymous, at 7:49 AM
Costco puts Nitrogen in all their tires...I had it done to my F-450 three years ago, and haven't had a loss of air since. Also, the tires have worn extremely well.
Dan - Arizona
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Anonymous, at 4:37 AM
Just how stupid do these people think we are? "Nitrogen has bigger molecules than air"! Aie is 80% nitrogen and nearly 20% oxygen with a small amout of carbondioxide and a few other inert gases. The exact mixture is readily available on the internet or any science handbook. So what about the misleading statements? Michelin seems to be on the right track. Valve stems and bead seals seem to be an overriding source of infaltion reducers. The big nitrogen for the RV'er is just so much BS.
By
merdon3538, at 5:16 AM
I've had nitrogen for two years now. The pressure has never dropped, nor does it sky rocket as the road temperature goes up. The article forget to mention that air contains oxygen which rots the tires from the inside out. From the inside where you can't see it. The only benefit of air was you check your tires (pressure only) once and awhile. Well, the bit you could see. My inside duals at the rear never got seen and testing their air pressure was limited to a rubber mallot. I'll keep the nitrogen. Thank you very much.
By
Anonymous, at 5:36 AM
I like to use Helium in my MH tires. Makes them so light the MH just "floats" down the highway.
By
Anonymous, at 7:14 AM
BOGUS! Normal "air" is 70% Nitrogen and 28% Oxygen-both about the same sized molecules. The other components are CO2 (larger size) and a very small amount of water vapor and depending on location various hydrocarbons. Nitrogen is acutally the samllest of these molecules if you have already removed the water vapor and thus it would seep out fastest. The reason to use pure Nitrogen is that it keeps out Oxygen and water which slowly oxidize the aluminum wheels and rubber. The process is more critical with aicraft wheels which use 300 psi that causes faster corrosion.
By
Anonymous, at 7:52 AM
Reality Check!
"Air" is about 79% nitrogen. So we all got nitrogen!
True there is about 20% oxygen and some other gasses. Oxygen will oxidise unprotected steel/aluminum, very slowly. Permiabilty of the rubber lining of the tire (usually butyl) is very slow, but check at least monthly. The main benefit of "nitrogen" is that it is dry, i.e. no water vapour. Many garages do not properly service their air compressors and thus you may get some moisture with your free air. Not the ideal situation but this is usually of no consequence.
Your choice, free or $10 X 7!
Jac
By
Jac, at 10:54 AM
Nitrogen in tires is only worth the expense if you routinely exceed 140mph and hav a risk of a dragging brake at that speed.
When I was at Boeing, I was involved in tires and brakes. Boeing recommends nitrogen bacuse of a couple of accidents when a very high wheel temperature, caused by a dragging brake during taxi-out and takeoff, resulted in spontaneous combustion of gases that had built up because of deterioration of the tire.
For road vehicles, the benefits are very hard to find and certainly don't warrant the cost.
Allan Damp
Anacortes, WA
By
dampnixon, at 11:01 AM
As pere CRC HAndbook of Chemistry and Physics, the molecular sizes of the three most bountiful molecules in air are:
Nitrogen (78% of Air) = 3.15 x 10 -8 cm
oxygen (20.8% of Air) = 2.98 x 10 -8 cm
Argon - < 1% of Air) = 2.88 x 10 -8 cm
as the size indicates, going to pure nitrogen would decrease the average moleculr size, less than 1%. Air planes use nitrogen, because of the water content of air, but not because it deteriates the rims nor the rubber - rather it is because at higher altitudes the water freezes and can dramatically reduce the pressure because of the change in volume when ever a gas freezes. None of the other gases are suceptible to the freezing effect.
By
Gary, at 1:47 PM
I know how to fill a tire with "dry" air. When I spray paint using a paint sprayer and an air compressor I have an inline water seperator that removes water from the airline. This should work with an air compressor for "airing" up tires.
By
The MANN, at 3:01 PM
Conrary to what has been said about the relative size of nitrogen & oxygen molocules, the home machines that provide oxygen use common air forced through filters to produce pure or nearly pure oxygen. There is a definite difference in molocule size in order for the machine to do this.
Lee
By
Anonymous, at 8:20 AM
I bought a new set of tires and a "lifetime" Nitrogen fill was offered for $25.00. I said "What the heck" and gave it a try. The guy told me to always check my pressure and that it is ok to add air, but it dilutes the nitrogen. He said that if I have to add air all I need to do when I return to town is bring the camper by and he will deflate the tire and replace with full Nitrogen for no charge.
By
Luvs2Camp, at 11:45 AM
It's amazing how many chemists there are on these forums! During the day you're working McDonald's but come night time when posting on forums like this, you're all chemists!
Consider these facts:
Pure nitrogen contains no oxygen and no moisture. Both of those are bad for your tires, rims, valve stems and seals. If you can eliminate them you have an automatic benefit for using nitrogen. Haven't you ever had bead seal leaks that require your tires to be dismounted, rim cleaned, and tire remounted? Nitrogen eliminates this.
With no moisture there is much less expansion and contraction leading to pressure changes that can set off tire pressure monitor systems.
It's true that 78% of what we breathe is already nitrogen. Is that supposed to be an argument against using nitrogen? Scientific studies have proven that unless the nitrogen in a tire is greater than 95%, it is useless.
Now we're listening to Michelin for tire maintenance advice? Doesn't Michelin want to sell you tires? Don't you think that gives them a bit of a biased opinion?
The fact is, there are definite advantages to nitrogen, I have seen it in my own vehicles. Scientific studies have shown the same results. In the near future car manufacturers will use it in new cars. When that happens, will you still call it a crock?
By
Anonymous, at 5:10 PM
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