Nitrogen in tires

Messages
1,799
Location
NJ now SC
A buddy of mine has a shop and just started using nitrogen. We filled all my vehicles tires. Costco now sells nitrogen. $3 a tire. Benefits are said to be Why Inflate with Nitrogen? Oxygen is your tire’s worst enemy. Air is about 78% nitrogen, 21% oxygen, and 1% other. Nitrogen is inert, non combustible, and non corrosive. Oxygen on the other hand is a destructive element. When tires are exposed to air, a long term and continuing deterioration begins - the oxidation of the rubber in the tire. What happens to a rubber band over time? It loses its elasticity and strength. This same process occurs in tires inflated with air as the oxygen attacks the rubber molecules, working from the inside out until the oxygen permeates the tire structure and ultimately the tread. Is All Nitrogen Gas Equal? No, nitrogen is available from nitrogen generators in different purities, generally ranging from 95% (low purity) to 99.9% (high purity). What Purity of Nitrogen Should I Use? All of our aging and longevity tests were with 98% or better. We strongly recommend that 98% or better be used to inflate your tires. What Are the Other Benefits of Nitrogen Inflation? Tires Last Longer On the road tests show that tires inflated with nitrogen lasted 25-30% longer and that road failures were reduced by 50%. Tires Hold Their Pressure Longer Nitrogen diffuses thru the walls of the tire 25-30% slower than air, significantly reducing tire pressure loss between inflation checks. Under inflated tires wear faster. A tire that is 10% underinflated will lose approximately 7% of its service life. Fewer Tire Failures The strength of tires are affected by oxidation, heat and pressure. Tires are weakened by the oxidation process, this process is accelerated by the heat generated from rolling. This oxidation is refered to as "fatigue" and "aging". Nitrogen filled tires had twice the life to failure in both field and laboratory tests. Better Fuel Mileage and Handling Tires that are properly inflated roll better than underinflated tires and get better fuel mileage. Tires that are properly inflated also respond better to steering input and handle better. Rims and Wheels Resist Rust Nitrogen produced by our systems is completely dry and without moisture rims and wheels are less likely to rust. Stronger Casings Mean More Retreads The lack of oxidation means that the tire casings remain stronger and can be retreaded additional times for longer tire life.
 
Messages
7,778
Location
Oklahoma
Military has used that for years. Especially on their SST aircraft. I kind of find it hard to believe some of their claims. It looks like to me, another way to squeeze money out of the customer for no real reason. I think ozone and UV light would be the worse enemy for a tire, and that would be on the outside.
 
Messages
421
Location
LUBBOCK, TX
I agree with Schmoe 99.9%. One other thing nitrogen does is to keep the pressure more constant because it is not affected by thermal expansion as much as air.
 
Messages
6,379
Location
San Francisco Bay Area
quote:
Originally posted by westex39: I agree with Schmoe 99.9%. One other thing nitrogen does is to keep the pressure more constant because it is not affected by thermal expansion as much as air.
That would only be due to the unpredictable thermal expansion of water vapor. Dry air would do just fine. Last year I help my folks bring back their car to Costco to remount a directional tire that was mounted backwards by them (long story). They charged $10 for a remount, but pumped nitrogen into all the tires at no extra charge. They even installed green valve stem caps. I don't buy "oxidation" or "leakage". Any modern tire has a liner to reduce air loss; nitrogen **might** resist leakage better through this lining. This (plastic) liner shouldn't be vunerable to oxidation. Your biggest worry about oxidation should be the effect of atmospheric oxygen on the tread compound.
 
Messages
11,360
Location
Florida, Cape Coral
When tires were made of NATURAL rubber they d oxidised quickly because of O2. Now we use synthetic rubber so no problem. The partial pressures of O2 & N will cause no problems with pressure differences. The only advantage of BOTTLED nitrogen or AIR is that it is DRY.
 

Colt

Thread starter
Messages
1,799
Location
NJ now SC
quote:
Originally posted by Eddie: . The only advantage of BOTTLED nitrogen or AIR is that it is DRY.
and thats what my buddy uses. Cylinders of 99.5% pure nitrogen. A cylinder only costs $23 to refill. . Don't know how many tires a 5-6ft cylinder fills but I got all vehicles for nothing along with a 10 gal air tank fill. [Big Grin] The air tank will just be available to add the pound or two loss in a few months.
 
Messages
943
Location
Central Valley, CA
Dry air works just as well as nitrogen, and thats what all the race cars are using these days (Pirelli exclusively uses dry air, I asked at Laguna Seca American LeMans last year). Air dryers/filters are less expensive in the long run, says the guy i talked to, then bottled nitrogen. The whole point of nitrogen is because it is much 'dryer' than 'air' just like Eddie said.
 
Messages
1,175
Location
Long Beach, CA
I've also been skeptical of the leakage issue. The reasons always go to the "size of the molecular nitrogen" (N2)...but nitrogen is the element ot the left of oxygen on the periodic table, so if anything the size of N2 compared to O2 would be smaller if anything...? Not that the molecular size difference between N2 and O2 would matter as any hole in a tire would be orders of magnitude larger than this tiny molecular/atomic difference.
 
Messages
16
Location
California
"Tires Hold Their Pressure Longer" If nitrogen holds pressure longer, then the tire will loose the 21% of the oxygen 1st. After inflating to replace the 21% of air lost, the percentage of oxygen in the tire will be 21% of 21%. If the process is repeated, sooner or later what's left in the tire will be close to 100% of nitrogen, for free!
 
Messages
1,967
Location
Kitsap, WA
Asked the les schwab boys about it the other day. They said after consideration they were NOT going to jump on the bandwagon at this time. The advantages were too small and additional costs to the customers didn't fit their style (trying to sell optional air). At the track we had n2 or co2 for tire adjustment(not fill) 1 reason, a small ez to carry bottle would last all season. An airtank would have been too big and bulky.
 
Messages
2,837
Location
MO
quote:
Originally posted by Floramar: "Tires Hold Their Pressure Longer" If nitrogen holds pressure longer, then the tire will loose the 21% of the oxygen 1st. After inflating to replace the 21% of air lost, the percentage of oxygen in the tire will be 21% of 21%. If the process is repeated, sooner or later what's left in the tire will be close to 100% of nitrogen, for free!
Brilliant!!!!!!!!!!!!!
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by Floramar: "Tires Hold Their Pressure Longer" If nitrogen holds pressure longer, then the tire will loose the 21% of the oxygen 1st. After inflating to replace the 21% of air lost, the percentage of oxygen in the tire will be 21% of 21%. If the process is repeated, sooner or later what's left in the tire will be close to 100% of nitrogen, for free!
I've been saying that for long time. Either tires function an an N2-O2 separating membrane or they don't. If they don't, then one of the primary arguments for N2 is BS. If they do, the same argument is moot.
 
Messages
783
Location
Austin Texas
quote:
Originally posted by y_p_w:
quote:
Originally posted by westex39: I agree with Schmoe 99.9%. One other thing nitrogen does is to keep the pressure more constant because it is not affected by thermal expansion as much as air.
That would only be due to the unpredictable thermal expansion of water vapor. Dry air would do just fine.

The thermal expansion of water into vapro is "very predictable" but highly nonlinear around the the bolng point of water. Tires used in agressive manners can and will get heated to this point (200dF) and the (rather) sudden air pressure rise as the tire overheats causes the tires to feel greasy. Nitrogen or dry air can reduce this effect markedly.
 
Messages
23,591
With a tire pressure monitoring system the nitrogen filling may well make (marginal) sense. Just by checking the tire pressure, you will lose a small amount of nirogen, and you still want to check your tire pressure. Because my car didn't have a tire pressure monitoring system, and because I still kept checking the tire pressure, I gave up on the nitrogen fill after using it a few times many years ago.
 

Kestas

Staff member
Messages
13,958
Location
The Motor City
quote:
Originally posted by ChrisW: Dry air works just as well as nitrogen....
So I guess it would be a beneficial for us anal folk to wait for a cold day in January when the dewpoint is 2°, then let all the air out of our tires, and refill it with dry ambient air. I guess "changing the air in your tire" during maintenance isn't such a joke after all!!
 
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