LFA951

Is anyone else out there using Nitro Fill and do you see any difference over air???

Cory9584

whats the difference? Is it supposed to be lighter or something?

ausgeflippt951

It doesn't leak nearly as fast, that's why people use it. Air is ~80% nitrogen, ~20% oxygen (w/ a little argon in there as well), and since nitrogen molecules are larger than oxygen, it doesn't leak as easily thru the tire/wheel. It's also relatively inert (compared to oxygen...has to do w/ electronegativity) and cheap (tho obviously not as cheap as air!). Price Club/Sam's Club will fill your tires for free.

It will also expand slightly less under heat, but will nevertheless expand just like air.

And yes, it is slightly lighter, tho essentially negligibly-so.

Driftomagnifico

No, they are comparably sized (nitrogen is triple bonded, and is smaller), and generally the lesser mass gas will permeate the bladder faster (nitrogen being lighter than oxygen). The tire itself is not designed to be semi-permeable for obvious reasons.

The main reason why race teams use it is because it is a dry gas. It does not contain water vapor and it involves less partial pressures. The result is a much more stable pressure gain curve as the tire warms up. As a result it gives more consistent tire temps for adjusting the pressure and setup.

ausgeflippt951

Just looked at my old chem book and I was wrong re: molecule sizes. But seriously, how can O2 "contain" water vapor when the water vapor is larger than the O2 molec's themselves?

Again, N2 is relatively inert (compared to O2) and is therefore more predicable under variable load (temp/heat, increased pressure, etc.)

...this makes me wonder if anyone's ever bothered to use argon?

Driftomagnifico

No person is stupid enough to fill their tire with oxygen, or at least I hope so. Normal air contains water vapor, oxygen, nitrogen, minute amounts of inert gasses (Argon, etc.) and traces of other gasses (H2, He, etc.). All of which is in your tires when you use an air compressor to fill the tire.

You could use argon, it's inert and gaseous. I'd be willing to bet that nitrogen is more readily available and equally suited for the role at a cheaper cost.

Driftomagnifico

Might want to revisit Mr. Chemistry book.

O=O vs. H-O-H

O2 is a larger molecule than H2O. H2O's bonds are more polar (the molecule is polar as well) and the valance shell structure of oxygen is very close to the nucleus which provides rather short bond lengths.

ausgeflippt951

Where are you getting this information, considering a double bond is physically shorter than a single. Plus, given HOH's polarity, it's got a pair of valence electrons at the top, thus forcing the molecule to physically take up more space. H2O is larger than O2. Oh also, bonds themselves cannot be polar. The molecule is made polar due to left-over valence electrons that shift the partial charge of the molec.

But back to the topic at-hand: yes, nitrogen is the best way to inflate your tires due mainly to cost...If I ever meet Schumi I'll have him drive a race car inflated w/ N2 and then w/ Ar and see if he can tell the difference!

Cory9584

how about helium

RKD in OKC

Pressure gain...

F1 tires are adjusted in 1/4 psi increments for handling. Street radials require almost 3 psi to make much difference in handling. These numbers are from Bridgestones F1 tire guy who does road racing himself.

Because of the huge pressure changes required to make much difference in street tires, I personally think nitrogen is not worth the effort for the street.

Track compounds are a whole nuther aminal.

RKD in OKC

Helium will cause the car to float in the turns.

Driftomagnifico

Don't see why not. It'll make your car lighter

Helium is kinda cost prohibitive compared to nitrogen and has zero benefit.

ausgeflippt951

Ha yeah, then your car would really sail! haha nah, it's not cost-effective, and its thermal conductivity is on-par w/ O2, thus giving it similar expansion properties.

Speaking of thermal conductivity, it just occurred to me that N2 is significantly lower than O2. This is good.

Driftomagnifico

Bonds can be polar in nature because of the transfer of electrons via DeltaEN. You have overall polarity and bond polarity (polar covalent).

2.75 Å is the molecular diameter of water (l)
2.90 Å is the molecular diameter of oxygen (g)
3.00 Å is the molecular diameter of nitrogen (g)

So nitrogen is larger, but barely enough to make a difference.

hosrom_951

The track pit guys during the DE told me that they use nitrogen in summer since they run much cooler than air.