I got a new set of tires coming in a couple days.
12-01-10, 07:31 PM
#16
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Its only $29.95 for the nitrogen. I think I may go for it especially if I can go for several years without filling my tires up and just to tell my friends that I have nitrogen in my tires.
Can u mix nitrogen and air in the tires. My guess is yes. I will also ask the dealership how many times I can come in in case I have to fill a tire up. Ya never know when ur going to run over a nail.
Can u mix nitrogen and air in the tires. My guess is yes. I will also ask the dealership how many times I can come in in case I have to fill a tire up. Ya never know when ur going to run over a nail.
12-01-10, 08:53 PM
#17
Seriously folks, paying for nitrogen on a normal street car is for total suckers.
Consumer Reports did a test over 1 full year. They found that over the whole year the nitrogen tires only lost 1.5 psi less than the normal air tires.
That's a nice, very tiny, benefit if it's free.
It's not worth paying for.
12-02-10, 10:53 AM
#19
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When I picked up my car a couple weeks ago, the dealer told me that the tires were already filled up with nitrogen, and that I could NOT "top it off" with regular air, only more nitrogen. If thats true its definitely not worth getting cuz of the added hassle of finding a place to fill up if tire pressure gets low.
Now I wonder if I can just drain the tires myself and fill it with regular air.
Now I wonder if I can just drain the tires myself and fill it with regular air.
12-02-10, 11:17 AM
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When I picked up my car a couple weeks ago, the dealer told me that the tires were already filled up with nitrogen, and that I could NOT "top it off" with regular air, only more nitrogen. If thats true its definitely not worth getting cuz of the added hassle of finding a place to fill up if tire pressure gets low.
Now I wonder if I can just drain the tires myself and fill it with regular air.
Now I wonder if I can just drain the tires myself and fill it with regular air.
12-02-10, 12:10 PM
#21
When I picked up my car a couple weeks ago, the dealer told me that the tires were already filled up with nitrogen, and that I could NOT "top it off" with regular air, only more nitrogen. If thats true its definitely not worth getting cuz of the added hassle of finding a place to fill up if tire pressure gets low.
Did you not read my post almost directly above your own?
Especially the part that points out-
12-02-10, 01:36 PM
#22
Nitrogen is inert...thus no boom boom!
Nitrogen molecules are bigger than air molecules so tire pressure does not bleed off or vary as much as air. I bought some tires for a pickup I don't drive much. I used nitrogen...despite not driving much...the air pressure stays very even over long periods of time
Nitrogen molecules are bigger than air molecules so tire pressure does not bleed off or vary as much as air. I bought some tires for a pickup I don't drive much. I used nitrogen...despite not driving much...the air pressure stays very even over long periods of time
Yes, nitrogen molecules are larger than oxygen molecules because atomic radius increases as one moves from right to left across the periodic table.
No, Nitrogen is not "inert." The only inert gases are the noble gases in period VIII - Helium, Neon, Argon, Krypton, Xenon, Radon.
Nitrogen does not readily react with oxygen under the temperature conditions present within a tire, though. I think that's what you meant to say. The marginal increases in temperature aren't enough to surpass the activation energy barrier for an N2+O2 reaction. There's no advantage nor disadvantage either way for pure nitrogen or air as far as reactivity goes.
You guys realize normal air is almost 80% nitrogen already, right?
Pure (or nearly pure) nitrogen does leak more slowly, but it's a really really small difference. Like 1-2 psi over a whole year difference.
So it's nice if you can get it for free, but certainly not worth paying for in a normally driven street car.
Pure (or nearly pure) nitrogen does leak more slowly, but it's a really really small difference. Like 1-2 psi over a whole year difference.
So it's nice if you can get it for free, but certainly not worth paying for in a normally driven street car.
PV = nRT
After a certain threshold PSI, volume changes within a tire are negligible and V can be considered a constant, thus
P = (nR/V)T = kT where k ~= constant
This is why it is important to measure and rectify tire pressure anomalies under cold conditions, because as your tires heat up (from driving), there will be a proportional increase in measured pressure that must be taken into account.
Pure nitrogen, however, does not have a "lower tendency to expand/contract" under temperature changes compared to a mixture of 77% nitrogen and 22% oxygen (i.e. "air").
When I picked up my car a couple weeks ago, the dealer told me that the tires were already filled up with nitrogen, and that I could NOT "top it off" with regular air, only more nitrogen. If thats true its definitely not worth getting cuz of the added hassle of finding a place to fill up if tire pressure gets low.
Now I wonder if I can just drain the tires myself and fill it with regular air.
Now I wonder if I can just drain the tires myself and fill it with regular air.
Kurtz is correct.
In addition to the (slight) advantages of pure nitrogen that have already been discussed, you also receive a slight weight advantage as well by filling your tires up with pure nitrogen over 77% nitrogen/22% oxygen.
Again, from the ideal gas law PV = nRT you can derive a corollary known as Avogadro's law which states that two equal containers (recall: after a certain threshold psi volume changes within a tire are negligible and V can be considered a constant) of gas at the same temperature (over the course of driving, temperature fluctuations are reasonably consistent in the case of pure nitrogen versus 77% nitrogen/22% oxygen) and pressure (P is relatively constant because this is the variable you actively control to keep it as constant as possible) contain the same number of particles.
n = (PV/RT) with P and V constants and T variable in a consistent way regardless of whether your tires are filled with pure nitrogen or air.
Nitrogen has a molecular mass of 14 g/mol whereas Oxygen as a molecular mass of 16 g/mol. In the case of air, the total pressure of the tire is equal to the partial pressure of nitrogen and the partial pressure of oxygen. In other words, both gases contribute to the total overall pressure.
In the case of pure nitrogen, however, the oxygen that was contributing to the total pressure in the first scenario is "replaced" with nitrogen which has a slightly lower molecular mass.
Given that the total number of particles are the same, you end up gaining a weight advantage equal to (2 grams/mol)*(# moles gas).
Again, it's negligible but it's still there. One day when I'm not feeling lazy, I might actually do a rough calculation to see just how much weight is saved by filling up one's tires with pure nitrogen over 77% nitrogen/22% oxygen.
12-02-10, 05:29 PM
#24
Close enough, I have dual B.S. in biochemistry and neuroscience, and I'm in medical school right now.
As far as cars are concerned, Kurtz knows far more than I do. I don't know much, but I can reason my way through basic physical principles pretty well when they are applicable. I've learned a whole lot about cars from Kurtz over the years.
As far as cars are concerned, Kurtz knows far more than I do. I don't know much, but I can reason my way through basic physical principles pretty well when they are applicable. I've learned a whole lot about cars from Kurtz over the years.
12-03-10, 06:21 PM
#29
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I'm filling my tires with helium so I can float down the highway...
Brandon
Edit: On a serious note... If you are adding air to your tire every month because the light keeps coming on, you need to go have you tire repaired/replaced.
Brandon
Edit: On a serious note... If you are adding air to your tire every month because the light keeps coming on, you need to go have you tire repaired/replaced.
Last edited by JUSROLLIN; 12-03-10 at 06:30 PM.
12-04-10, 12:44 AM
#30
I am carLx; I changed my name to syzygy not too long ago. Kurtz and I are different people, however, despite the fact that our matter-of-fact posting styles are often similar.