Nitrogen in tires - PeachParts Mercedes-Benz Forum

vahe · #1 08-04-2006, 12:14 PM

What is this that I read in papers about filling tires with Nitrogen and get 1 to 2 more mpg?
Anyone has the poop and scoop?

Vahe
240D 77 350K

Hatterasguy · #2 08-04-2006, 12:29 PM

The air you breath is 80% nitrogen, pure marketing bs.

JEREMYC · #3 08-04-2006, 12:36 PM

Actually, it is not pure marketing BS. I have my tires filled with nitrogen and so does my dad. It made a 2 mpg diff in my 05 accord hybrid and it made a 1-2 mpg diff in his 06 Dodge Cummins 1-ton 4x4.

Hatterasguy · #4 08-04-2006, 12:41 PM

Sure; this is the make up of air, 78% nitrogen and 21% oxygen, trace amounts of other gases, and water vapor.

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

Please explain to me how a 22% increase of nitrogen in your tires will affect anything.

JEREMYC · #5 08-04-2006, 12:49 PM

I'm no scientist so I can not explain how it makes a difference. I too was skeptical about it at first for the same reasons you are. My buddy did it in his 05 Silverado and it gained him about 2 mpg on the highway. I tried it cause I got it done for free and I went from 42mpg average in the Hybrid to just under 44mpg average. I have had it in my tires for about 4 months now. Seems to be doing ok.

#6 08-04-2006, 12:59 PM

The only potential benefit would be the lack of water vapor in N2, compared to normal air. In other words, using N2 should be about the same as using dry air. This may cause the pressure to respond more predictably to temperature changes. I don't see how using N2 would increase mileage unless it is simply being run at higher pressures.

BTW, do the purge the air out of the tire before they fill it with N2? If not, only about 2/3 will be N2, the rest will still be air.

TMAllison · #7 08-04-2006, 01:02 PM

Not a scientist either....I suspect your increase in milage is a result of new tires and the tendency of most tires stores to inflate them to the maximum allowed as shown on the sidewall.

First thing I do after buying tires is air down to level I desire to promote proper wear and handling the following morning.

I suspect because you have *purchased* nitrogen there may be a tendency to leave them over-inflated?

JEREMYC · #8 08-04-2006, 01:12 PM

I got mine done for free from a friend that owns a tire shop. I did not specify the inflation pressure to him. Just took the car to him and went back by to pick it up later in the day. I did see another car in his shop he was doing because I asked him why that car was sitting on four flats because it was a new Altima with new tires. He said he was putting nitrogen in them too. I checked my psi on my tires and it is at 34-35psi. Sounds pretty normal.

mj_sid · #9 08-04-2006, 01:14 PM

When I got my new tires they filled it with nitrogen as part of the setup. My understanding is that it is a larger molecule than oxygen and does not loose pressure as quickly as oxygen.

Who Knows? I didn’t cost me anything and I figured it couldn’t hurt anything so what the heck.

--Matt

winmutt · #10 08-04-2006, 01:49 PM

Perhaps as the tires heat up on the highway they expand more? Higher pressure?

Dervman · #11 08-04-2006, 01:57 PM

My understanding is that when filled with nitrogen the tires heat up less and are more stable. As already mentioned because it is Dry Air and does not easily absorb moisture this avoids the added weight of water droplets and possible imbalance caused by any significant build-up.

I do know that all the serious Race Teams use Nitrogen in their tires, so there must be something to this.

jnc19610 · #12 08-04-2006, 03:20 PM

Because they use bottled gas in the pits.

I crewed on an IMSA team in the 80's. We used nitrogen, mostly because it was there. We could get compressed air cylinders to use for the air jacks and center lugnuts, or we could get nitrogen. We usually got nitrogen.

vstech · #13 08-04-2006, 03:42 PM

if your tires are currently underinflated, getting proper, or overinflation will of course affect MPG, other than that. hooie.
there is not available power for most racers in the pits, and aircompressors are difficult to move around. a single 3000psi cyllinder could keep tires and tools running for weeks.
the water vapor quetion removed by the compressor so mostly dry air in tires, water vapor is negligible. oxygen can cause tires to deteriorate, but they still contact air on outside of tire... so only the higher pressure air inside tire... hmm. highpressure oxygen could be damaging the tire... nahh, I don't buy it.
I will dump all the air I can out of my tires...and inflate with N2, since I have a cyllinder. but I doubt it will make any diff. I have all mileage records for the last 3 years on my suburban. lets see if it changes at all.
John

bgkast · #14 08-04-2006, 03:44 PM

I have a feeling that the mileage increases because the tires are inflated to, or past, the specified pressure when the nitrogen is put in, verses under-inflated when filled with air.

dunl · #15 08-04-2006, 03:57 PM

Has anyone tested their inflation pressure compared to mileage BEFORE refilling with nitrogen and comparing the results?

If not, you can't say it improved because of the the nitrogen, if you aren't aware of exactly what the tire pressure was before refilling.

And yes, I'm skeptical that an increase of about 20% nitrogen is going to do anything.