Nitrogen in your tires: an inflated idea?
Advocates say filling your tires with the gas instead of air will help
keep correct pressure and better gas mileage.

By TOM ZUCCO, Times Staff Writer
Published September 28, 2005

Gassing up your car is about to take on a new meaning.
Fill your tires with pure nitrogen and you'll get better gas mileage,
advocates of the practice say. Your tires will be safer, and they'll
last longer.
A colorless, odorless, tasteless gas that makes up about 78 percent of
the Earth's atmosphere, nitrogen could cost you as much as $10 a tire.
But what you save on gas, tire replacement and peace of mind will make
up the difference, according to the pitch.
Already, retailers like Costco and Olin Mott stores offer nitrogen, and
Pep Boys has test-marketed it.
Starting Saturday, buyers of all new cars sold at select Crown
dealerships in the Tampa Bay area will find their tires filled with
nitrogen. Eventually, all 13 dealerships will offer it.
The thinking is that nitrogen's larger molecules prevent it from seeping
out of a tire as quickly as air. So inflating tires with nearly pure
nitrogen - which has been done for years in race cars, commercial
airliners and long-distance trucks - allows them to retain correct
pressure longer.
Pressure is vital because a properly inflated tire is a safer, more
efficient tire. The National Highway Traffic Safety Administration says
most drivers can improve gas mileage by nearly 3 percent by keeping
their vehicle tires within the recommended pressure range. The
government also estimates the nation loses more than 2 million gallons
of gas every day due to underinflated tires.
Enter nitrogen. Chemical No. 7 on your periodic chart of the elements.
At anywhere from $2 to $10 per tire.
Besides attracting customers and addressing safety concerns, it's a way
to fight inflation. Or rather, the lack of it, said Jim Myers, Crown's
chief operating officer.
"The whole theory is that air bleeds through the tire slowly," Myers
said. "And if someone isn't diligent, any tire will lose air over time.
But because of nitrogen's properties, that doesn't happen as quickly."
Myers said Crown will also offer to replace air with nitrogen on any
vehicle for $39.
What happens if tire pressure drops and the driver is not near a garage
or tire store that sells nitrogen?
Topping off with compressed air won't hurt, tire experts say, and the
tire can be purged and refilled with nitrogen later.
So should motorists feel ... pressured to put nitrogen in their tires?
"It sounds like it has mostly positive points," said Randy Bly, director
of community relations for AAA Auto Club South in Tampa. "Nitrogen helps
keep tires cooler under open highway conditions, and it's less likely to
leak out, so that would help with fuel mileage.
"The only negative would be the cost. But it may well be worth it."
Nitrogen-filled tires stay inflated about three times as long as than
air-filled tires, advocates say, and while a typical tire inflated with
compressed air might lose 2.7 pounds of pressure monthly, one filled
with nitrogen loses 0.7 pound.
But Jim Davis, public relations manager for Goodyear Tire and Rubber,
says replacing air with nitrogen is "a tough call."
"The objective is to have the correct air pressure," Davis said. "And
over time, minute amounts of air do leak out.
"There is no harm to the tire from using regular air. But we urge people
to check their tires monthly."
What happens, Davis said, is that decreased air pressure flattens a
tire, creating more surface area between the tire and the road. That
added friction can make the engine work harder and cause tires to
overheat, possibly leading to a blowout.
"More tire surface means it takes more power to roll that tire," Davis
said. "A correctly inflated tire is going to roll more easily."
Checking tires for correct pressure also has a side benefit.
"When you're down there, look at the tires," Davis said. "You may notice
a nail or tread that is wearing abnormally, and you can catch it before
the problem becomes worse."
At least one tire manufacturer is even more skeptical about the
advantages of nitrogen in the family car.
Michelin officials recommend nitrogen only for tires used "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)," according to a company
statement.
But for all other tires in normal use, nitrogen "is not required and
does not necessarily bring the expected benefit.
"It is true that the physical properties of nitrogen reduce the pressure
loss due to the natural permeability of the materials of the tire and
thus the broad use of nitrogen will in general assist motorists with
pressure maintenance.
"Nevertheless, 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."
So we can save the expense if we just check our tires regularly.
The trouble is, we don't.
As recently as two years ago, government and tire industry surveys
showed close to 30 percent of cars, vans, pickups and SUVs on the road
had at least one tire that was substantially underinflated, at least 8
psi below the recommended minimum pressure.
But high gas prices and consumer education may be cutting into that
number. According to a survey by Uniroyal Tire in mid August, nearly 50
percent of Americans said they are now checking the air pressure in
their tires once a month.
Still, that leaves millions of unchecked tires.
"Most people don't take care of their tires on a regular basis," said
Dave Zielasko, editor and publisher of Tire Business , an Akron, Ohio,
trade publication. "Tires are one of the most underappreciated part of
the vehicle. People take them for granted. But the reality is they do
need to be checked.
"Remember, it's the only part of the vehicle that touches the road."

I bet a nickel it's a good bit more than 1% in Los Angeles.
--scott

Unless one was considering keeping the tire mounted for 30 years on the
same rim I don't think that is an issue.

Yup, that's what I would think too.

It won't hurt, and as long as it is free and easy to use then sure, why
not use nitrogen.

I suspect that the only tire deterioration of any consequence is the
result of tread-to-road contact. The rest of this supposed problem is
the result of guys looking for some new automotive problem to worry
about and a few entrepreneurs who are willing to provide an imaginary
solution.

I figure there's so much oxygen inside the tire. If it's combining
with some element of the tires, pretty soon all the oxygen will be
used up in the process of damaging the tire. However, the outside
of the tire is constantly exposed to fresh air with 21% unconsumed
oxygen, and therefore should deteriorate much, much faster than
the inside of the tire.

I've never seen oxygen damage on the outside of any tire, I've never
seen any oxygen damage on the inside of old tires removed from cars,
and I've never ever heard of an oxygen failure of a tire.

Whatever else might be in the air you put in a tire, it's going to
be consumed in the process of combining with the tire to cause
damage; and the outside of the tire will be constantly exposed to
much, much more of the same.

Now, as to whether there's any advantage regarding inflation
pressure change from cold to hot, deponent further says not.

I've seen those claims too. Even if they're right, I've never had a tire
"decompose" in my almost 5 decades of driving. They either wear out or get
damaged long before this happens. So I agree that its probably a gimmick.

I'm amazed how many of you in USA have not tried *nitrogen, when
your petrol costs 1½x of prices in msia, must be due to your shops'
higher charges from costlier labour.

In 11-04, 1 tyre shop here was confident that users would like the
benefits, & offered for 4 days free *.  I was amazed by their confidence
so took their offer : got * pumped into 4 Michelin "green" tyres ( 205
& 195/65R15 @2.3kg/cm² ) with the lowest rolling resistance (rr) I
know & already aligned to parallel ( no toe-in / out ).
I think my tyres' rr dropped by 3-5% ( based on my accord's minimum
tow force needed ), but tyres with very low aspect ratio ( little air / gas
) may feel nothing.  My 6½" alloy wheels are now much cooler, &
receive less shock ( over bumps ) than before.  Steering is lighter too. I
got the same results from 2 more cars' 70 series tyres. Tyres need not
be pumped as often as before, i.e. saves time : my 4 Michelins' * need
not be added, for 14 months !
I think these 5 benefits come from *'s lower molecular friction than air.
Disadvantages are [i] I must not use a pressure gauge [ii] driving over
bumps, or hitting kerbs, will need more care, to avoid losing *.

   Its actually 6 of one, half dozen of another..... the only advantage I
see with using nitrogen is that it will keep your tires up for a longer
period of time and I believe the only reason for that is because it has
something to do with density of nitrogen as opposed to oxygen.  It takes
longer to leak out (nitrogen).  Another advantage is on racetracks.....but
unless you use the road as one, there is no advantage there.  Nitrogen will
also not compress as quickly... it is a bit more stable than oxygen...

anything I missed?

Fwed

I have a proprietary blend of ozone, methyl bromide,  sulfur trioxode,
and water vapor.

I discovered it when I was a Weblo, retiring.
It made such a boom in the trade,  it was suppressed,
just like the Pogue carburetor.  

And you will have to adjust the mix of helium as you change altitude.
That car could just go floating off into the sunset!!!

Helium filled boots are your best bet.
You'll save on fuel,  and on speeding tickets!

But you'll lose traction.  So a RWD car should have helium in the front
and co2 or xenon or radon in the back then? ;)