Nitrogen in tires

[tnpartsguy]

Got my tires switched over to Nitrogen filled Friday. Got about 2 hours away from home and had a flat due to a dryrotted valvestem that SHOULD have been replaced when the new tires were put on. SO, my left front tire went the rest of the trip with plain old air in it.....but overall, I DID see improved gas mileage, 28 mpg average over my normal 26 on the same trip. The leg down with the low tire was horrid though, and I didn't count it in the average (14 mpg during that leg). On Nitrogen filled tires On not replacing the valve stems when replacing tires Too bad I didn't have a low tire pressure system...... as you really can't fell a low tire with AWD until it's very very low.

[Raven]

What does it cost for a nitrogen fill? In other words, how much gas will you need to save to break even?

[jake75]

My theory is that you should fill your tires with helium because that would give you extra "lift" essentially reducing the effective weight of your vehicile and we know that the weight of a vehicle affects mileage. Why if you were only getting 32.0000 mpg before, I am sure you might get as much as 32.0001 mpg with helium filled tires.

[millster]

Sunny, around here there was a place offering the service for something like $20 US for all four corners. They claim that the nitrogen won't tend to leak out like regular air over time so once you do it you shouldn't have to do it again for a long time unless you get a puncture. I don't know though. I'm still a skeptic.As for the helium idea Jake, I realize it was a joke, but it still brought to mind the question. If someone did that, what effect would that have on traction and would it make the car more prone to hydroplaning? Not to mention the fact that I think everyone has seen how a helium balloon looks after a week. Again, I realize it was in jest. So don't take my questions as anything more than rambling.

[northvibe]

tnpartsguy - so with going with nitrogen, is it recommended to get new tires? sounds like a neat idea, i should consult my physics teacher about this and see what she says.

[DavidPIL]

hiya...I thought the only benefit for nitrogen filled tires is that it's less prone to the expansion and contraction from heat/driving. Not sure what benefits that would have either but I'm sure there would be some. Never heard of the mpg improvements. hmm, learn something new every day.Dave

[tnpartsguy]

http://ezinearticles.com/?Sell...38142$5/tire is the going rate around here. They have to completely deflate, then re inflate with Nitrogen, then repeat to get all the old air evacuated. Took about 45 minutes.

[the1stacekiller]

I am pretty sure Costco offers this service with new tire install.. but I can't remember if its free or for a cost..cheers

[1oldbanjo]

I feel I need to comment on this one - my research has led to pretty conflicting stories.The air we breath is approximately 78% nitrogen, 20% oxygen and 2% trace elements like Helium, Methane, Hydorgen, CO2, etc. So just filling your tires with air will put 78% nitrogen in your tires right from the start.The theory that nitrogen leaks out through the tire slower seems to not be supported by chemistry or gas laws. Nitrogen is not a bigger atom than Oxygen - Oxygen is just slightly larger - so 98% (nitrogen and oxygen) of the air in your tire should leak out at about the same rate as Nitrogen alone. The 2% other gases can be very small and may leak out very quickly. Ever see how fast a Helium filled balloon loses air compared to one filled with air?The gas constants in chemistry/physics also provide that the expansion of nitrogen and air within normal operating temperatures are pretty comparable - so your street driven car will not heat the tires up enough to make much of a difference between nitrogen and air. If you go on a trip with 32 psi of nitrogen in your tire or 32 psi of air in your tire - you will get the same mpg.Some sources claim that aircraft use nitrogen because it is very dry and has little or no moisture in it - so that when the aircraft encounter -50 degree temperatures the water vapor will not condense and freeze in the tire. Other sources agree with this concept and claim that the automobile racers use it because water vapor in compressed air can expand when the tires are used in competition and the amount of water vapor is dependant upon the humidity and the effectiveness of any air/water seperators used in the air compressor and piping - and the dryer nitrogen will not expand and alter the tire pressures as a tire used in competition will.One other source states that Nitrogen does not promote deterioration of the inside of the tire by Oxidation - which can happen with air. You will however wear your tire out long before any oxidation from the inside of the tire causes you problems - when have you ever seen a tire with more oxidation/weathering on the inside of the tire than on the outside?The bottom line seems to be that the race teams use Nitrogen to avoid inconsistent presures as a result of water vapor - and because filling tires from a high pressure nitrogen bottle that will fill their tires and run their air tools is more convenient than having to drag around a compressor. Also it appears that Nitrogen Inflation for street driven cars is a modern sales gimmick - and not really a necessity if you keep your tires inflated within a pound or two of the ideal tire pressure for your car. Remember that the more air you have in your tire the better mpg you will get as the tire will be harder and will roll easier - but at some point the tire will be over inflated and you will start wearing the tire out in the center of the tread. If you put wider tires on your car you will probably need to drop the pressure a little bit to make your tires wear evenly.As for me.....I buy my tires at a place that does use nitrogen inflation...but I just think it is a sales gimmick and I buy my tires there as I get good service and a good price since we have company vehicles and buy several sets of tires a year from them. As long as the nitrogen stays in there I will use it - but I am not going to pay anybody extra to put any in there. It will not save me any money or get me any better mpg - I check my tire pressure regularly.

[zionzr2]

Quote, originally posted by 1oldbanjo »I feel I need to comment on this one - my research has led to pretty conflicting stories.The air we breath is approximately 78% nitrogen, 20% oxygen and 2% trace elements like Helium, Methane, Hydorgen, CO2, etc. So just filling your tires with air will put 78% nitrogen in your tires right from the start.The theory that nitrogen leaks out through the tire slower seems to not be supported by chemistry or gas laws. Nitrogen is not a bigger atom than Oxygen - Oxygen is just slightly larger - so 98% (nitrogen and oxygen) of the air in your tire should leak out at about the same rate as Nitrogen alone. The 2% other gases can be very small and may leak out very quickly. Ever see how fast a Helium filled balloon loses air compared to one filled with air?The gas constants in chemistry/physics also provide that the expansion of nitrogen and air within normal operating temperatures are pretty comparable - so your street driven car will not heat the tires up enough to make much of a difference between nitrogen and air. If you go on a trip with 32 psi of nitrogen in your tire or 32 psi of air in your tire - you will get the same mpg.Some sources claim that aircraft use nitrogen because it is very dry and has little or no moisture in it - so that when the aircraft encounter -50 degree temperatures the water vapor will not condense and freeze in the tire. Other sources agree with this concept and claim that the automobile racers use it because water vapor in compressed air can expand when the tires are used in competition and the amount of water vapor is dependant upon the humidity and the effectiveness of any air/water seperators used in the air compressor and piping - and the dryer nitrogen will not expand and alter the tire pressures as a tire used in competition will.One other source states that Nitrogen does not promote deterioration of the inside of the tire by Oxidation - which can happen with air. You will however wear your tire out long before any oxidation from the inside of the tire causes you problems - when have you ever seen a tire with more oxidation/weathering on the inside of the tire than on the outside?The bottom line seems to be that the race teams use Nitrogen to avoid inconsistent presures as a result of water vapor - and because filling tires from a high pressure nitrogen bottle that will fill their tires and run their air tools is more convenient than having to drag around a compressor. Also it appears that Nitrogen Inflation for street driven cars is a modern sales gimmick - and not really a necessity if you keep your tires inflated within a pound or two of the ideal tire pressure for your car. Remember that the more air you have in your tire the better mpg you will get as the tire will be harder and will roll easier - but at some point the tire will be over inflated and you will start wearing the tire out in the center of the tread. If you put wider tires on your car you will probably need to drop the pressure a little bit to make your tires wear evenly.As for me.....I buy my tires at a place that does use nitrogen inflation...but I just think it is a sales gimmick and I buy my tires there as I get good service and a good price since we have company vehicles and buy several sets of tires a year from them. As long as the nitrogen stays in there I will use it - but I am not going to pay anybody extra to put any in there. It will not save me any money or get me any better mpg - I check my tire pressure regularly. I would have to agree!! I'm not going to pay $20 for Nitrogen in my tires when air is free... Several gas stations in my area have free air.

[1oldbanjo]

I just found a site for a Nitrogen Dispensing maching that that has lots of information on Nitrogen. Two interesting things are that they claim Nitrogen molucules are 4 times larger than oxygen - and that the seller can get a 1,000% profit on selling nitrogen to us consumers! Here is the address for the site: http://www.gwrauto.com/nitroge...e.htmLast night I thought that if anyone really wants to find out how much difference it makes - just get two identical balloons and fill one up from your air compressor and one up with nitrogen - and see if the air filled balloon shrinks faster than the nitrogen filled balloon. This test would be accelerated more than would happen in your tires - as the rubber is much thinner. I may stop by my local tire store and see if they will do that for me. I will also do some more exploring about thye difference between molecular weights, molecule size and number of molecules in a given volume/pressure.

[LUVROK]

I use CO2 beacuse it is quick. I keep a 20 lb tank in my Jeep for airing up the tires quickly when in the middle of the woods. I typically air down a set of 35" or 37" tires to 7 psi for the woods and back up to 23 psi for the street. It also helps to re-seal a lost bead after peeling a wheel open against a rock and hammering it back to shape. Nitrogen is a gimmick and as stated is used in racing to decrease the amount of condensation and thus expansion and contraction due to changes in pressure.If you are paying $5 a fill per tire for a teeny little car tire you are being ripped off. I pay $20 to fill my 20 lb tank with CO2. Nitrogen is the same cost but I don't have a Nitrogen regulator as at 20lbs it is still in gaseous tate where CO2 is in liquid state. 20 lbs is enough to fill 50 or 60 35" tires from 7 psi to 23 psi. That's the equivalent of at least 150 car tires.

[ragingfish]

Quote, originally posted by millster »As for the helium idea Jake, I realize it was a joke, but it still brought to mind the question. If someone did that, what effect would that have on traction and would it make the car more prone to hydroplaning? Not to mention the fact that I think everyone has seen how a helium balloon looks after a week. Again, I realize it was in jest. So don't take my questions as anything more than rambling. Here are my thoughts...When you fill a balloon with helium, and let it go, it drifts up to the ceiling and through the laws of Murphy it lands right in front of a light. Usually within an hour or two, the helium inside expands so much that it causes the balloon to explode. I would be concerned how helium would react to the increasing heat of the tire on a long trip...Yes, air can explode a balloon and/or tire too. But from my experiences, helium does it a hell of a lot faster...and IIRC, helium expands more then air when heated. I could be wrong though...chemistry was never my strong suit...

[redlava]

I don't think the balloon popping was caused by the nitrogen expanding. The heat from the light bulb over time was enough to degrade the thin rubber of the balloon and the air pressure inside of it just pushed it past it's breaking point. The nitrogen in tires sounds like a snake oil scam to me. Just one way for a tire company to screw you out of a few more bucks by scaring you into an unwarranted purchase. I could see if you were a race car driver it might help a little. But for your average Joe Blow on the city street it is completely useless. If you bought good tires and had them installed correctly they shouldn't leak much air anyway. In the three and a half years I had my stock Eagles on I probably only had to put air in them 3 times.I would skip out on the nitrogen unless 20 extra bucks doesn't matter all to much to you.

[GMJAP]

1oldbanjo -Terrific post! Thanks.Quote, originally posted by millster »As for the helium idea Jake, I realize it was a joke, but it still brought to mind the question. If someone did that, what effect would that have on traction and would it make the car more prone to hydroplaning? Not to mention the fact that I think everyone has seen how a helium balloon looks after a week. Again, I realize it was in jest. So don't take my questions as anything more than rambling. Remember, the gas in your tires is compressed. Helium balloons rise because it is (about) the same pressure as the air, but weighs less for the same volume of air it displaces. In your tires, the difference in weight is going to be difference between the weight of the volume of normal air in your tires at 32psi versus the weight of the volume of helium in the tires at 32psi.You understand that air weighs very little, so the difference between air and helium would be very small. A few ounces per tire, likely.Finally, any weight reduction due to helium would not affect mileage and performance as much as removing that much weight from the vehicle. That's because the mass of the car is fundementally unchanged, and it's moving that mass from point A to point B that consumes a lot of the energy. Only the tire friction on the road surface would be affected by weight loss due to helium (But whether or not you have a soda in the car will make more difference than filling your tires with helium )

[coldmm803]

when i got new tires they put the nitrogen in, i dont know that i can say yet whether or not it has increased my milage untill the spring when it gets warm again. the part about leaking out slower i'm not sure i agree with, within 2 weeks my tires dropped 2 psi. however, they did highly over inflate the tires so that large decrease could be a result of the tires being too full.with the stock conti's i have managed 40mpg a few times. on my trip back to campus after thanksgiving i managed 35mpg with the new michelins and that was with a lot of speed variation due to traffic

[ragingfish]

Quote, originally posted by coldmm803 »within 2 weeks my tires dropped 2 psi. however, they did highly over inflate the tires so that large decrease could be a result of the tires being too full.i hope not! tires shouldn't bleed air (or N2), even if overfilled. They should have as much of an air-tight seal as possible. And with "normal" air, you shouldn't lose more then about 1-2psi per month, certainly not per week!With "normal" air inflation, a drop of 2 psi could most likely be attributed to the drastic change in ambient temperatures and weather over the last two weeks...they say you can attribute a 1 pound change in tire pressure for every 10 degree change in ambient air temp.So if the temperatures drop 20 degrees (which is about what they dropped around here in the last two weeks), you should expect a 2 pound loss in tire pressure.With N2 however, I just dunno. You shouldn't see much, if any, change in PSI regardless of temps...one of the selling points of using it as an inflation gas...

[JohnC]

High dollar snake oil for your tires...hmmm wish I would have thought of this. $$$$$$. Oh-well I'll just go back to playing with my Pet Rock.Anyone know where to buy fuel magnets, Tornado intake air flow stabilizers or a car that runs on H2O?

[ragingfish]

Here's a good read on filling your tires with N2... http://www.techcentralstation.com/111604D.html[