So, I'm not entirely sure why nitrogen is better than air, other than it doesn't leak as much, or why it would give better mileage, but mehbe someone could figure this out and explain it to me? Also, where do one go to fill their tires with nitrogen? I don't know many nitrogen stations around...Seems like a good thing to test though, I must say.
I think I heard once that nitrogen is used because it isn't affected by temperature like air is. Your tire pressure doesn't go up when you drive. If that's true, it would sure make testing for benefits of increased tire inflation on mpgs. I've never heard where you get the nitrogen though.
Horsepower is how hard you hit the wall, torque is how much of the wall you take with you.
So, it's time to resurrect an old thread. On my last car, Nitrogen-fill was standard on any new tire purchase. So, right now, I'm sitting in Indy watching TV, and a local tire store advertises that, "We fill all of our tires with Nitrogen, so you get better gas mileage!" I thought, OK, you're going to explain this right? The spokesmodel said, "Nitrogen is resistant to heating up as you drive, keeping your tires cooler, and you get better mileage!"
OK -- I understand that warmer tires yield better traction in cornering due to higher friction, but does this carry-over into straight-line driving? Second, it's basically a given that tire over-inflation gives you better economy. So my hypothesis is that 1) It's a gimmick to charge a little more, and 2) SUV drivers' underinflated tires may stay cooler and not blow-out.
For me, I'll stick with "air" and let the tires heat-up and increase in pressure as I drive to increase FE. Isn't the air around us 70-some% Nitrogen anyways?
Air is 78% nitrogen. It couldn't be much better with all nitrogen, people just have a real problem with keeping their tires inflated. I see tires low all the time, I want to make a sign saying your tires are low! --Many people wouldn't even know what to do. I talked to a few people at school and I had one person who didn't check their pressure in 9 months because their car was ''new''...
__________________ Current Stable
GasSaver: 2000 Honda Insight Silverstone w/AC 65+mpg
Track Terror: 2002 Honda S2000 Gran Prix White- lots of mods - 28mpg
Beater: 1988 Honda Civic DX Hatback - Stripped - 30mpg
RIP: 1996 Honda Civic LX 42mpg - you will be missed
I think the only way you would get better mileage is because Nitrogen doesn't leak down as fast thus the folks that never check their pressure will not lose as much air between oil changes when they have Jiffy lube check it.
I checked my tires after each leg of my 26 mile commute the temps were 89 and 93 and the increase in pressure was only 4 PSI.
I tend to agree that nitrogen shouldn't help with mileage all that much, doesn't tire presure go up with highway driving/hot tires?
however in theory nitrogen filled tires should last longer due to the lack of 02 and water vapor in the tire, reducing rust in steel rims, and tire rot in all tubes and tires, this would be most affective in bicycle tires, motorcycle tires, and tires on vehicles that tend to sit.
you can get your very own tank of nitrogen from brew suply stores.
I used to work as a lineman at an airport FBO and we used nitrogen in the rental aircraft tires. Supposedly it was for the safety aspect of it.
They use nitrogen in planes for several reason: Less air loss during temperature extremes, keeps moisture out for rust, you don't have to worry about it freezing when at altitude, and to keep the heat down when the tires go from 0 MPH up over 130 MPH or more when landing and taking off. Not to mention the incredible heat generated by braking. It's really amazing when you think about the abuse they receive and how much weight they support.
This is my first post here... I had to comment on this.
I cannot see how nitrogen in tires would keep them significantly cooler than air. The specific heat of nitrogen is about 30% higher than air, but there simply isn't enough mass there to really make a difference. The mass of the tire and rim dominates the situation. Could it be viscous heating of the gas due to tire rotation? I think the gas would simply rotate with the tire and not have much viscous dissipation.
Also, how can nitrogen leak so much more slowly than air? Air is 78% nitrogen, so is the oyxgen leaking out? If so, eventually we would be left with just nitrogen in our tires anyway, as the oxygen is leaking out and leaving the nitrogen behind.
Nitrogen rises in pressure when heated the same as air does (neglecting very tiny differences to to gas compressibility, on the order of 0.05%). Most all gasses behave like ideal gasses at low pressure and temperature (much less than critical pressure/temperature).
I could see a benefit with corrosion but honestly, when was the last time a rim rusted away from the inside out?
I say it's a scam.
Before you say I don't know what I'm talking about, I'm an engineer in the R&D department of a company which makes instruments to measure gas flow. I know a little bit about gasses. I also have a masters degree in mechanical engineering (heat transfer and fluid mechanics). I do like to learn new things though, if I'm wrong please explain.