On Dec 21, 7:39*pm, brian whatcott wrote:

And the funny thing is: I know plane tires are often nitrogen filled,
but I can't imagine why. The bottled gas man said there is a growing
market for nitrogen from the local car dealers too. And that seems even
more unlikely.
Perhaps I'm biased - but I watched the Myth-busters doing their worst to
set a tire on fire, up to and including pouring gasoline over it
while making smoke with a muscle car - and failing!

Merry Christmas!

Brian Whatcott
Altus OK

Aircraft tires are usually filled with nitrogen, as on the big stuff,
the tire pressure is often well above 100 psi. Combined with big
volumes of air, and brakes that can be glowing cherry red (if not even
dripping a little metal every now and then), if one of them babies
lets go, you will have one heck of a fire in no time. If you add to
this the possiblity of a ruptured tire taking out a brake line and
spewing hydraulic fluid onto the brake along with air (oxygen) under
pressure, well, you can guess what will happen. So, the reason for
Nitrogen in aircraft tires is to remove the oxidizer from near the
ignition source, as even the roughly 20% oxygen in the air we compress
is enough to fuel a big fire on aircraft brakes.

On the other hand, that muscle car has big tires, and low pressure. I
seem to recall that the top fuel racers are running between 3 and 5
psi in their slicks. Big volume, but not much flow if one lets go.
The rubber on the tire melts at way below the ignition temperature, so
that is probably why the Myth Busters couldn't get it to catch fire.

So, why nitrogen for car tires? Easy Money. I tell you that if I
fill your tires with Nitrogen, it won't leak out as fast as air, so
you will get better gas mileage, and it will only cost you $45 for me
to do it, many will pay that $45. And since I am filling from a big
bottle that it costs me $25 to re-fill, and I can service probably 15
cars at $45 each, I can bring in $675 from a $25 re-curring cost, it
won't take me long to pay for my cart and be bringing in one of the
highest profit margins I have seen in a LONG time.

I will stick with the 78% nitrogen I get from my air compressor for my
tires.

Oh, yeah. And since Nitrogen is an inert gas, meaning it doesn't
support combustion, why do you think Shell is advertising "Nitrogen
Enriched Gasoline" to improve your mileage and increase the life of
your engine? You want to put something that won't burn in my gas, and
tell me you are doing a good thing? "Yes sir" he said with a smile on
his face.

Maybe DG can sell nitrogen for their tires? :-)

Steve Leonard
Wichita, KS