Nitrogen or air?

[i_got_a_mohawk]

Regular air is good enough. The big push for nitrogen around here is it's not supposed to leak out of the tires as fast as regular air is, since the molecules are bigger.

The difference in size between an O2 molecule and N2 molecule is pretty tiny (relatively). So I doubt that will make a difference.

OP, have you heard of Tara Labs power cables? Now, you might think spending over $1000 on a power cable won't make any difference . . .

 

[Chunk-O-Funk]

Thanks...Free coupon so why not. How much wold it cost to purge all the air out of the tires and fill them with nitrogen if I did not have a coupon? Now that I will have nitrogen in them do I have to continue to use nitrogen?

I think it's about a $40.00 service.
No, you do not have to refill with nitrogen. For instance, if you pick up a nail in your tire and or have a slow leak you can fill it with regular old air.

 

[NJL]

.

 

[JacoLesFlea]

I think it's about a $40.00 service.
No, you do not have to refill with nitrogen. For instance, if you pick up a nail in your tire and or have a slow leak you can fill it with regular old air.

Thanks

 

[Papazita]

To truly test the efficacy of nitrogen-filled tires vs air-filled, try the following test:

Using the aforementioned red Sharpie, write the following on each tire: EVERYTHING IS SAFE INSIDE EVERYTHING IS SAFE INSIDE EVERYTHING IS SAFE INSIDE > O.K.
Now, drive the car for 50 miles on the nitro tires; take them off and leave them in a field behind a tree. Then put on the air tires and drive another 75 miles. Next, take the air tires off and try to drive with no tires at all.
Notice the difference?

 

[xgator4u]

Thanks...Free coupon so why not. How much wold it cost to purge all the air out of the tires and fill them with nitrogen if I did not have a coupon? Now that I will have nitrogen in them do I have to continue to use nitrogen?

Yeah I got the same coupon deal at the dealership where I got my wife's car. The nitro don't seem to need fooling with much, it's free and if a tire gets a little low ( like at the change of seasons) [even though that is minimal in Florida] all she has to do is pull in to the dealer and they check all the pressures, correct them on all the tires for FREE as long as you got the special valve stem caps. Kinda like FULL service gas stations used to be. Man, Now I am showing my age.

 

[BassyBill]

pV=nRT

Nitrogen expands and contracts with temperature changes just like any other gas.

As for the molecules being bigger - bigger than what?

 

[i_got_a_mohawk]

I was pretty sure on that aswell but couldnt remember the equation to post it up

Im guessing they are meaning bigger than oxygen, which they are, N2 is slightly bigger than O2, and when I mean slightly, I mean slightly! Talking in the region of about 2% larger. Unless they are talking about the other consituents of air, which makes up all of about 1%

 

[Petebass]

Regular air is good enough. The big push for nitrogen around here is it's not supposed to leak out of the tires as fast as regular air is, since the molecules are bigger. So in that case if I fill my tires to 41 psi, when the leak down to 32 psi I should have nothing but nitrogen left.

Fwiw I've been in the business for 26 years and I've yet to see any difference in any tire with or without a nitrogen fill, other than the pretty green valve caps.

I got new tyres in December 2006, and got the nitrogen on the basis of "it's probably a load of marketing BS but it's free so why not". We get nice red valve caps over here.

2+ years later, I have never had to top up the air pressure in those tyres. I check them every now and again and they ALWAYS read 35psi. I can guarantee that's never happened when I was using normal air.

Having said that, normal air works perfectly well, especially if you're like me and are already in the habit of checking tyre pressures semi-regularly. Is it really that much effort to pump up your tyres after you're filled the gas tank?

 

[Papazita]

Is it really that much effort to pump up your tyres after you're filled the gas tank?

No, it's just that manuvering around the blue-haired grannies and hotrodding "my daddy bought me a new Beemer" kids who seem hell-bent on causing as many accidents as possible in the gas station lot, just to get from the gas pump to the air pump, makes it a bit of a pain.

Seriously...just a few weeks ago i saw one little old lady hit not one, but FOUR other vehicles, AND a pump! :scowl:

 

[JacoLesFlea]

Yeah I got the same coupon deal at the dealership where I got my wife's car. The nitro don't seem to need fooling with much, it's free and if a tire gets a little low ( like at the change of seasons) [even though that is minimal in Florida] all she has to do is pull in to the dealer and they check all the pressures, correct them on all the tires for FREE as long as you got the special valve stem caps. Kinda like FULL service gas stations used to be. Man, Now I am showing my age.

thank you

 

[BassyBill]

I was pretty sure on that aswell but couldnt remember the equation to post it up

Im guessing they are meaning bigger than oxygen, which they are, N2 is slightly bigger than O2, and when I mean slightly, I mean slightly! Talking in the region of about 2% larger. Unless they are talking about the other consituents of air, which makes up all of about 1%

Just looked up the relative sizes of these molecules; nitrogen about 300pm, oxygen about 292pm. But I think it is the case that a small difference in size can make a bigger difference in permeability rates, depending on the actual structure of the polymer molecules in the tyre wall. So I guess it could be true that the 20% or so of air that is oxygen could get out of your tyres just a bit quicker than the nitrogen, and using all nitrogen could slow this down a little.

The bit about expansion and contraction still stands, though. If you get two tyres inflated to the same pressure under the same conditions, then they should behave just the same way as far as pressure fluctuations with temperature go; the chemical makeup of the gases in each tyre will make no difference (as long as the gases are behaving ideally, which will certainly be true at the sort of temperatures and pressures you get inside a tyre). I think the only way you could notice a difference would be if you used air that was really, really humid and then dropped the temperature really cold so all the moisture condensed or even froze, effectively decreasing the amount of gas in the tyre.

 

[Eric Perry]

Bill, wth is a tyre???

 

[Kenbuntu]

Its the correct way of spelling tire.

 

[Petebass]

Its the correct way of spelling tire.

"Tire" is what happens to me after I exercise. A "Tyre" is a rubber round thing

 

[Pilgrim]

Nitrogen fills = a way to empty your wallet.

They have no function on standard passenger car tires.

Its the correct way of spelling tire.

Y'all don't live in Texas, do ya son? Down there it's "tar".

 

[tycobb73]

one thing to keep in mind, if you have to put a little air in your tires that are ntrogen filled, all gains are lost.

 

[Bassgrinder77]

ALL gasses expand (or increase in pressure) with increased temperature:
P*V = n*R*T
It's the law (of the universe).

That's it, right there. Pure nitrogen doesn't expand / contract based on temps. Motorcycle shocks are factory filled with nitrogen to maintain consistency. Whether it makes a bit of difference on car tires is anyone's guess, me thinks.

 

[Thunderscreech]

I will fill my tires with propane gas.

This will be lots of fun.

 

[fdeck]

Diffusion rates are not simply a matter of molecular size.