Nitrogen is undiputedly better than plain air, but the costs do not seem to
make this a good deal, unless the car will be driven only a small amount
each year, and the main threat to the lifetime of the tires is internal
sidewall degradation from aging (oxidation).
Nitrogen, being slightly less dense than oxygen, has larger molecules which
will leak out of the tire a bit more slowly. Nitrogen also does not expand
and contract quite as much with changes in temperature, so tire pressures
stay a bit more constant. This means, however, that nitrogen-filled tires
should be filled to a slightly higher "cold" pressure, as the normal (air)
pressures assume a heating rate when driving that is appropriate for
Aircraft tires can benefit significantly from nitrogen, as they are used in
a much harsher environment than car tires. Nitrogen is also virtually
inert, so cannot feed a fire the same way the oxygen in air can.
Costco Cda uses nitrogen in their tire service bays. I wondered whether or
not the moisture content injected with nitrogen is similar as the moisture
injected from air pumps at regular gas bars. I have stopped using gas bar
air pumps due to the vast amount of moisture ejected by those units. Do we
need to be concerned with water in our tires?
Wheel-well fires are a serious threat on aircraft. It seems all of the
higher speed aircraft uses nitrogen. My aircraft I fill up every month.
The inner tubes are natural rubber and hence bleed out the air. Not like
on cars. Yep, innertubes! Two piece rims.
If you regularly check and maintain your tire pressure with dry air,
then nitrogen has no meaningful benefits in your car tires.
With air, if the atomsphere is humid and the compressor does not have
well-maintained drying equipment, it can cause corrosion on the wheel
and valve stem. Wet air will also have more variance in pressure as
the tire temperature rises and falls. Most service stations and even
many tire shops do not have quality dryers for the compressed air
lines. Nitrogen systems remove water as well as oxygen, so this can
be a benefit.
Also, if you are forgetful and many months typically go by between
your tire pressure checks, nitrogen will maintain the pressure longer.
This means you can get a somewhat false sense of security, but your
safety and fuel economy will be maintained longer with no maintenance.
Nitrogen inflation is not an excuse to neglect your tire pressure!
You need to ask yourself how much these benefits are worth to you.
On Fri, 19 Jan 2007 10:15:45 -0500, Jay Somerset
Air is mostly nitrogen (~78%) and the rest is mostly oxygen (~21%). Long
There are two reasons to use nitrogen instead of the same air you breath.
One is that nitrogen is typically dry compared to room air. If you worry
about small amounts of water vapor in your tires, you will view this as a
The other is that oxygen is a corrosive gave and MAY cause earlier internal
aging of your tires and any corrosion-labile things inside the wheel/tire
Given that the outside of you tires is nicely bathed in air, I see little
point in worrying about oxygen inside the tire.
If you have too much money, go waste it on nitrogen fills if you like. Just
don't expect any benefit.
The last 3 cars I've owned (1997 ES300, 1987 Acura Legend Coupe, 1983
Firebird) all developed leaky/corroded rims after about 3 to 5 years.
The tires start to lose pressure and when I go to the tire store they
say that the slow leak is caused by corroded rims. They sand down the
rim and reseal the tubeless tires. Sometimes the tires still leaked a
little. The tire store warned me that they can only sand down the rims
so much before I'll need to replace the rims.
I wonder if this corrosion could have been reduced or avoided by using
nitrogen? I live in the Northeast Ohio (Cleveland) area.
Nitrogen-filled tires may slow down the corrosion a little. Most gas
station and home compressors do not have driers so moisture goes into the
tire along with the compressed air, causing some corrosion from the inside.
Nicks, scrapes, and salt allow corrosion to start from the outside of the
wheel. Alloy wheels have a clear coat, and if the clear coat is damaged,
the wheels corrode more quickly and they become porous. IMO, sanding the
wheel rim without applying another protective coating accelerates the
corrosion process. A longer-lasting solution would be to re-clearcoat the
wheel. I have the tire shop apply a generous coating of bead sealer on the
entire inside of the wheel and rim before installing the tire. Washing any
salt accumulation off as soon as possible, and applying clear nail polish to
any nicks and scratches will also slow down corrosion.
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
I fill my tires (not often enough) at gas stations when I can find one
with an air pump. Moisture has never been a concern before since this
is the first time I've become aware of the issue despite asking
mechanics repeatedly why the rims corrode.
So, where should I get my tires filled?
And what should I do about the (moist) air that's already in them?
I fill my tires with my home compressor, and the filter/drier on it is
pretty worthless. When using air tools that use a lot of air, the tool's
exhaust will be dripping water after a while. A quality drier system will
cost as much or more than a home compressor, so I just make sure to use
plenty of air tool oil in my air tools.
For me personally, it is a lot easier to get a shop to coat the inside of
the wheel with bead sealer and fill my tires at home or a convenient air
source than it is to have to take it to a shop that has nitrogen generators.
The moisture-laden air in my tires theoretically will have greater variances
in tire air pressure than dry air, but those variances are not enough to
cause a problem.
A really bad choice! Helium is the gas with the very smallest molecules --
even smaller than hydrogen, which has 2 atoms per molecule. Helium will
leak out of almost any container faster than any other gas, due to its small
Apart from that factor, it would be ideal (although very expensive) as it is
inert. It's light weight is not a real bonus however, as even the weight of
air in a tire is negligible, compared to the weight of the tire and wheel.
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