OT: Nitrogen filled tires

[Bob Myers]

"dead inert"? a *fluoride* compound? It even sounds toxic.

Google it and see. If you don't think fluoride compounds
can be inert, I would suggest you consider Teflon....

Bob M.

 

[Clifford Heath]

PV = nRT for any gas, right?

Yes, but delta-T is balanced by both delta-V and delta-P,
because the tire yields, so the balance of delta-V over
delta-P depends on the gamma of the gas... roll on CO2 for
tires, its gamma is just over 1.3, c.f. 1.41 for air/N2.

Clifford Heath.

 

[Paul Hovnanian P.E.]

Try CO2.

 

[Glenn Gundlach]

"dead inert"? a *fluoride* compound? It even sounds toxic.

You didn't see the science guy on Leno a few weeks back? Fish tank
full of sulfur hexaflouride with an aluminum foil boat floating in
air. Then they took a stun gun shooting sparks and put it into the
tank and all sparking stopped. Leno took a lungful and instead of the
high pitched helium talk turned into Barry White. Some other neat
tricks to light candles.

http://en.wikipedia.org/wiki/Sulfur_hexafluoride

GG

 

[[email protected]]

Next time, insist on Helium. Places that fill tires with
Helium instead of Nitrogen always have lots of repeat
customers, so it *must* be good!

A related question: I am about to install new speakers in
my convertible. Should I point them to the rear for better
gas mileage, or point them up for better traction? :0

Install a hydraulic system for them just like jets... point them up as
spoilers and for more traction, point them down like flaps for more
lift, when cruising on the freeway point them towards the rear.

haha

 

[Don Klipstein]

"dead inert"? a *fluoride* compound? It even sounds toxic.

The Wiki article on that compound says that room temperature chemical
reactions are largely unknown, and that SF6 even does not react with
molten sodium! Xenon is more reactive - actually has at least one
biological effect if inhaled, and I mean other than displacing oxygen.
It has a "general anesthetic" effect that other "inert" and the truly
unert gases lack. And SF6 lacks that effect.

It does start to decompose at 500 degrees C however, according to that
same article. Also not too good to have sparks/arcs that SF6 fails to
completely supress. The decomposition products *mostly* recombine into
SF6, but only mostly!

- Don Klipstein ([email protected])

 

[Nico Coesel]

Mine have nitrogen in them. I've got a lifetime free refill plan
(part of the usual lifetime service plan, it was cheap), the tire
station makes the N2 itself from air. In my case, the water and

Wow, some people actually managed to sell air!

They claim the tire pressure is less affected by the tire temperature,
too, which may account for the 3% fuel savings in that article.
Truckers spend a LOT of money on fuel, so tiny savings are a big deal.

A truck makes whole lot more miles or km than a car. And a truck also
consumes a lot more fuel. So a saving of 1% is quite a lot of money.
It is even economical to install LPG injection in diesel powered
trucks.

 

[redbelly]

Good for up to about 10 atmospheres. Then you get to use something
else to compensate since the gas is no longer ideal.

http://en.wikipedia.org/wiki/Equati.../en.wikipedia.org/wiki/Van_der_Waals_equation

Michael

Even so, a car tire is usually inflated to just around 3 atmospheres.

(Eg. 30 psi-gauge, which is 45 psi-absolute or 3 atm.)

Mark

 

[default]

Things seem pretty slow in SED today, so let's talk about "Hot Air".
(Like the kind in your tires.)

Every so often I read something like this:
http://fleetowner.com/news/topstory/fleet_nitrogren_beats_air/
suggesting Nitrogen is better than air for improved mileage, lower
tire wear, reduced Global Warming, etc....

The trick is you fill your tires with Nitrogen instead of compressed
air.

Huh?! Air is 78% (or so) Nitrogen anyway.
Is there anything to this, or is this a classic signal-to-noise
problem...??
Notice too that the article does not mention any service stations so
equipped...

-mpm

$100 to replace the air with nitrogen? They "suck" the air out and
change it.

Suck a partial vacuum on a tire and you unseat one bead and then your
sucking room air through.

Why not just add a refrigerated dryer, molecular sieve or desiccant
upstream of the nozzle or tank and remove the moisture from the air
source?

 

[Michael A. Terrell]

You could fill a tire with a high-molecular-weight gas, like a freon
or something, and it might leak less.

I used to fill my bicycle tires with propane, for that reason and to
avoid pumping. Of course, that has at least two tricky side effects.

When you have a blowout, you really have a BLOWOUT!


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Except that "n" changes when you hit the dew point.

At least, that's my guess. I just don't want the water and oxygen
inside my tires any more. It sucks changing a tire in a snowstorm.

Snowstorm? Do they still have those? ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[krw]

However, there is a very significant difference between
the conditions under which a racing tire operates - for
all of its hour or so (if that) of life - and those seen in
passenger-car service. Do you think that MIGHT have
something to do with the use of nitrogen in racing, such that
those same reasons wouldn't apply at all in everyday use?

OTOH, the racing tire doesn't sit on the car for five years, rotting
away from the inside.

 

[krw]

It would be useful if Drexan's cost per nitrogen fill-up were given -
then, one could determine the break-even time, if any, for the whole
fleet, using nitrogen fill-ups vs. the cost of the additional fuel
consumed. Since this information is not given, though, I'm going by
the $100 per fill-up quoted in the Car Talk article... and, clearly,
there, it is not worth it for the individual user. $100 can buy at
least two fill-ups for my Camry (though, probably not for an SUV...)

Costco, and others, use only Nitrogen. No additional cost.

 

[krw]

"suck out the _old_ N2..."

I have that done twice a year to my wife's car. When I get back home
it'll be past time to replace the summer air with winter air[*]. If
we get an early snow storm, I'll be a dead man. :-(
..

Bwahahahahahaha!

Must be Slowman's kid ;-)

[*] The air gets changed along with the rubber; no additional
charge. ;-)

 

[Straw Man]

"suck out the _old_ N2..."

I have that done twice a year to my wife's car. When I get back home
it'll be past time to replace the summer air with winter air[*]. If
we get an early snow storm, I'll be a dead man. :-(
.

Bwahahahahahaha!

Must be Slowman's kid ;-)

[*] The air gets changed along with the rubber; no additional
charge. ;-)

I put Helium in my tires so the car floats.

 

[Rich Grise]

Things seem pretty slow in SED today, so let's talk about "Hot Air". (Like
the kind in your tires.)

Every so often I read something like this:
http://fleetowner.com/news/topstory/fleet_nitrogren_beats_air/ suggesting
Nitrogen is better than air for improved mileage, lower tire wear, reduced
Global Warming, etc....

The trick is you fill your tires with Nitrogen instead of compressed air.

Huh?! Air is 78% (or so) Nitrogen anyway. Is there anything to this, or
is this a classic signal-to-noise problem...??
Notice too that the article does not mention any service stations so
equipped...

When I was in the USAF, at one point I worked on the SR-71 Blackbird
http://www.google.com/search?hl=en&q="sr-71+blackbird"

and they used dry nitrogen in its tires. But the reason, they told me,
didn't have anything to do with gas mileage, it was so that when it
lands at about 300 MPH, the tires don't explode and burn. Hot rubber
and oxygen can get a little volatile.

But, for a car, the only difference I can think of would have to do
with condensation, and just using dry air should alleviate any risk
in that area.

IOW, if somebody's making a claim like that, and expecially[SIC] if
they're trying to sell you something (like nitrogen), then they're
just blowing smoke up your ears, so to speak.

Hope This Helps!
Rich

 

[Meat Plow]

Things seem pretty slow in SED today, so let's talk about "Hot Air". (Like
the kind in your tires.)

Every so often I read something like this:
http://fleetowner.com/news/topstory/fleet_nitrogren_beats_air/ suggesting
Nitrogen is better than air for improved mileage, lower tire wear, reduced
Global Warming, etc....

The trick is you fill your tires with Nitrogen instead of compressed air.

Huh?! Air is 78% (or so) Nitrogen anyway. Is there anything to this, or
is this a classic signal-to-noise problem...??
Notice too that the article does not mention any service stations so
equipped...

When I was in the USAF, at one point I worked on the SR-71 Blackbird
http://www.google.com/search?hl=en&q="sr-71+blackbird"

and they used dry nitrogen in its tires. But the reason, they told me,
didn't have anything to do with gas mileage, it was so that when it
lands at about 300 MPH, the tires don't explode and burn. Hot rubber
and oxygen can get a little volatile.

But, for a car, the only difference I can think of would have to do
with condensation, and just using dry air should alleviate any risk
in that area.

IOW, if somebody's making a claim like that, and expecially[SIC] if
they're trying to sell you something (like nitrogen), then they're
just blowing smoke up your ears, so to speak.

Hope This Helps!
Rich

I think all aircraft tires get nitrogen because it lessens the chance of
corrosion.

 

[Rich Grise]

Mine have nitrogen in them. I've got a lifetime free refill plan (part of
the usual lifetime service plan, it was cheap), ...

Just exactly how "cheap"?

Thanks,
Rich

 

[Rich Grise]

PV = nRT for any gas, right?

Yeah, sure, if nR = K. ;-)

Cheers!
Rich

 

[Rich Grise]

"dead inert"? a *fluoride* compound? It even sounds toxic.

Well, yeah, it "sounds" toxic. But I think you're simply reacting
to "fluoride" hysteria.

In fact, it's *practically* inert - it's even less reactive than dry
nitrogen.

When I was in the USAF, we actually used SF6 to pressurize some high-
voltage power supplies - apparently at altitude, it has a better
breakdown voltage than plain air.

And if you fill up a balloon with it, it drops like a rock. (well,
maybe like a whiffle ball or nerf ball.)

I've even heard that it's been used as a filler gas for deep dives;
it doesn't give you nitrogen narcosis, and it doesn't make your
voice go funny like helium does. (at least, at pressure. If you take a
lungful of SF6 at atomspheric pressure, you sound like Isaac Hayes until
it dissipates. ;-)

Cheers!
Rich