I saw some place claiming that nitrogen in tyres results in less pressure variation with temperature, that's why racing cars use it. Huh? My high-school physics told me PV=nRT i.e. pressure is proportional to absolute temperature, whatever gas
My guess is that nitrogen will contain less water vapor. Otherwise, I think you're right about this.
I think the whole nitrogen-tire thing was oversold as folks "never having to check their pressures again". Blame marketing.
Yes, the variation in pressure per 10degrees F will be less than 1 lb PSI, but tires should still be checked monthly(or more freq) for deflation due to other factors - faulty or damaged valves, slow leaks due to a nail picked up or a clipped curb.
Common sense above all applies.
Semi OT: Man I just wish my dealer and the tire place would stop putting the TIRE PLACARD pressure in my tires! Maximum cold pressures listed on modern tires are often far more than the 35PSI cold we remember for ages.
My wife's pro contacts has 47psi in them all around, suggesting the dealer service techs went by the 51psi max pressure cold on those placards.
Last month mine were at 40psi(tire placard on mine says 41psi cold). These pressures were between 10-20 FRICKN psi OVER what the b-piller stickers recommended cold!! Is it too much for you to put down the air hose, OPEN MY DOOR and read the pressures listed here?
Door sticker plus 2-4psi would be fine, thank you! That way the tires would be about spec the next morning.
You didn't allow for moisture content of the regular air you're breathing now.
Nitrogen makes a niggling difference where every other variable has been maximized and where every small detail is critical, i.e., not us going to the grocery.
to check their pressures again". Blame marketing.
The real advantage to nitrogen is that it is free of oil and water unlike t ypical shop air. The water is what causes increased pressure variation with temperature, so that part is somewhat true although of limited concern to your average street driver. I guess buying bottled nitrogen to fill tires is cheaper than installing a filter/dryer system to make the shop air clini cally clean - which would cause other problems, as traditionally shops have actually used oilers on their air lines to introduce extra oil to prolong the life of pneumatic tools.
, but tires should still be checked monthly(or more freq) for deflation due to other factors - faulty or damaged valves, slow leaks due to a nail pick ed up or a clipped curb.
the TIRE PLACARD pressure in my tires! Maximum cold pressures listed on m odern tires are often far more than the 35PSI cold we remember for ages.
r service techs went by the 51psi max pressure cold on those placards.
kers recommended cold!! Is it too much for you to put down the air hose, O PEN MY DOOR and read the pressures listed here?
ould be about spec the next morning.
Far too often those stickers are completely missing when a car is repainted ... although I suppose that is better than leaving the door jambs a differe nt color (which I have also seen...)
N8N wrote: "Far too often those stickers are completely missing when a car is repainted... although I suppose that is better than leaving the door jam bs a different color (which I have also seen...) "
That's no excuse for a tech to just go and look. And if not, it's better t o put in 5lbs PSI below the maximum listed on the tire than to put in exact ly what that placard stays. That way the customer is not driving home in a basketball, and they can just set them correctly the next morning.
Nitrogen makes a significant different to people who are in long haul trucking and every penny counts. That's where the whole thing came from. I think it can save them something like 2% in fuel costs. When you are spending thousands of dollars on fuel for a single trip, 2% starts to add up.
Lots of information here
But who did those tests? If there were tests that said the effect is infintessimal, I doubt we would see them touted.
They use it for fire protection, just as military and US commercial jets do, because 100% nitrogen doesn't help fires burn. Someone mentioned, 10-20 years ago, that a German airline wanted to fly to the US with a tire filled with ordinary air, but the US FAA prohibited it, so a nitrogen-filled tire was shipped to the airliner.
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