several garages around here, including Costco, are now offering to fill-up your tires with Nitrogen instead of air. Does anyone know what the advantages are if any, or is this just another ploy to get some money out of us?

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

enough said

Air is 80 percent nitrogen anyway....

__________________
I love my cars to death but my wallet sure doesn't.

they say the nitrogen keeps your tire from deterioating...

they say it keeps your rim from rusting on the inside.

I always fill my tires with Unobtanium.

Never fails, never leaks, never rusts .... never find it. Simply just nevers.

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

As far as I know the only benefit to nitrogen is supposedly it does not loose pressure with temp changes etc... stays more stable. I beleive the Costco here fills your tires with it if you want for free assuming you buy the tires from them.

__________________
1991 300E 3.0 - Stock 134k (My "new" baby)
2003 Jeep Liberty

Is really for the haves and don't want to be bothered to get their fat a** out to check tire pressure.

Nitrogen is within air 80% already. Doing this is up to 100%.
Is like racing u spend another few hundred grand only to improve a few milli secs. To some is worth it.

Or your 12 sec quarter mile car will still stop at the red light along with the 30 secs 1/4 mile car. So the haves should have the right to drive on express lane with min speed of 200MPH.

Another thead with discussion of this issure.

http://forums.rennlist.com/rennforums/showthread.php?t=211549&highlight=nitrogen

There are some small advantages to using nitrogen (aircraft routinely use nitrogen). One, it dosn't expand or contract as air at temperature variations and two, it does not hold moisture as does air. Also tires do not seem to leak down using nitrogen (molecules are bigger?).
I have used nitrogen for 10 years just because it is readily available to me and it does have some minor benefits. Works fine for me.
Al

Air is about 78 percent N2, 20 percent O2, and the remaining two percent consists of trace amounts of Argon, other gases and, of course, water vapor.

Both air and N2 behave as ideal gases and follow Boyle's Law (Pv=RT), so there is no difference in themal pressure rise, but the wild card is water vapor. N2 and O2 molecules are about the same size and neither has a greater propensity than the other to bleed though the tire or bead seals.

If you fill the tires on a warm humid day and then the ambient temperature drops below the dew point, some water vapor can condense out as liquid water, which will reduce pressure until the tire heats up enough to evaporate the water.

For this reason I always run my compressor to fill the tank when humidity is relatively low, then let the tank cool and open the bleed valve to remove any condensed water vapor from the bottom of the tank. I also have a water trap in the supply line. Once the tank cools to ambient temperature, the pressure drop through the regulator will reduce temperature and cause excess moisture to condense out and be caught in the water trap, so the air that ends up in my tires is pretty dry.

The argument that N2 will prevent oxidation of the inside tire surface may be a valid, but most modern tire materials resist oxidation quite well, and there is always some O2 that remains in the tires. Even if N2 is used to initially air the tire to seal the beads and bring them up to bead seating pressure (about 45-50 psi), you won't purge all the O2 and water vapor.

So if you have a handy supply of dry N2, it's not a bad idea to use it to fill your tires, but in the event that you don't, take precaution to minimize the amount of moisture that gets into your air supply.

A properly sealed tire should lose no more than 1-2 psi per month. If more you have a leak, but keep in mind that if you fill the tires at 80F and the temperature drops to 40 they could loose about one psi just from the colder temperature.

Normal driving will heat up the tire and its contained air and increase pressure readings 3-6 psi, and running on a race track will increase pressure 8-12 psi.

If the car is sitting in the sun, solar radiation can heat up the tires and increase pressure several psi relative to the shady side.

It's best to check TP in the morning when the air is cool and the car is in the garage or shade.

Duke

Why not fill with helium instead, then your car will really fly! Or how about hydrogen, if your car's a real bomb!

It's not that far-fetched an idea. What is against this for the masses is that
we're not likely to benefit from this substitution in the real world of rush hr
traffic and commuting. I can see where it might be helpful, for example, in
cross country, long haul travels. Nitrogen has been part of the gas charged
equation with shocks for some years, racing, and as earlier mentioned, aviation.
But more down to earth, we're nearly always will do just fine with the manual
or electric pump we already have at home.

A few months ago there was a news blitz that we should replace tires older than 6 year, regardless of how much tread is left, and now nitrogen is supposed to make tires last longer. Longer than what? It will be thrown away after 6 years anyway.

But then again, Harry, there's guys like me that only put 3K on their car in any given year, and old tires can be a real concern.

BTW, I just replaced the 19 year old tires on my Cutlass. They were WAY overdue! I won't let that happen again.

__________________
95 E320 Cabriolet, 159K

Wow, this went around in the sixties, claiming the moisture in compressors put water vapor in the tires. It probably is a more stable gas, and if high speed runs heated your tires? I have not heard of it being used in competition like in NASCAR!