Heard of this 2 different times today. Anyone know anything about it ?? I guess Chrysler is doing this with some of their tires.
Nitrogen does not contract and expand with the heat like air does. So once you put that in your tires you never have to check the tire pressure again. They put a cap on the valve so when green you are good, if red you have a leak. Helpful.
Have no idea what it costs.
But is interesting.
Anyone know of it - try it - any feedback ??
After all, going from Texas to Los Angeles and up thru Wyoming definitely will have some temperature changes.
Thanks
Rusty & Cheryl 2011 F250 2WD 6.2L Gasser 2008 Weekend Warrior FB2100
"Common sense is in spite of, not the result of, education" - Victor Hugo (1802-1885)
If it's free there is no down-side, if it costs money then you got sold some snake oil.
Fact is pure Nitrogen and DRY air follow the same temperature/pressure rules as any other gas.
The key is DRY air, if there is moisture in your tires then the readings will vary.
And yes, air is already 78% nitrogen.
My truck has air in its tires, my trailer has Nitrogen (because that's what the tire shop uses). I have a TST pressure monitoring system. The pressures and temperatures of the truck and trailer tires go up and down together and the pressure changes are the same percentage.
Like I said - no down side, but don't spend money on it!
Keith J.
1999 Sunnybrook 27RKFS Fiver.
2005 GMC Sierra 2500HD CC/SB/DA 2WD, LBZ air cleaner, 52 gal Titan tank, Bilsteins, Line-X, Westin steps, Prodigy, Retrax cover, 16K Superglide, 5th-Airborne pin-box, Multi-vex mirrors, TST TPMS.
Tire cap pressure indicators have been around for some time. You buy them for the pressure you want to indicate up to 120 psi http://www.eagleday.com/vitiprin.html has some good info on them do not know if they are the best price or not.
Nitrogen or not you still have to check your tire pressure on a regular basis. Nails don't care if there is nitrogen in your tires or air, they will still leak the same with a nail in them.
Supposedly, nitrogen will not vary quite as much as air (which as has been noted, is already 78% nitrogen) due to temperature changes, but it will still vary, as has been noted above. Most race cars use nitrogen for that reason. An additional bonus to nitrogen is the fact that since it is a larger molecule, it will not leak/seep out as readily as air. Is the difference worth paying for? Not in my opinion, but to each his own.
Most shops that use nitrogen will replace the caps with green caps simply as an indication to others that nitrogen was used. There's nothing special about those caps other than their color. There are also caps available (been around for quite some time) that have a clear top with an internal pressure guage built in; green showing means good pressure, red showing means low pressure. They can be purchased for several specific pressure ranges. However, air or nitrogen makes no difference, they simply read the pressure.
We don't stop playing because we grow old...We grow old because we stop playing!
Very interesting - especially KeeDeeJay running both with a pressure set up.
Thanks. Does not sound like I'll be spending any time looking for someone who does that to find out what they charge.
If done properly I don't think you should see the same pressure rise in your tires. There is a special way of doing it where they vacuum the "impure" air out and put in 100% nitrogen. I work in the auto industry and a lot of our dealerships are just now getting on board with the nitrogen machines. Do a google search for "nitrofill" and you'll find lots of FAQ's about it. In my opinion it's not a scam really because it will make your tires last longer and there will be less pressure variance with temperature changes so there are some benefits. Some dealerships are even front loading it to every car they have on the lot (and of course marking the price up a little but that's another story I don't think anywhere it says you never have to check your pressure again...that would probably be too much chance for a lawsuit!
I personally don't have it because you are only supposed to add regular air (like you'd get at a gas station) in an emergency and if you do, you have to go back to the dealership to have the nitrogen redone in that tire. I'd rather just check my pressures regularly. Nitrogen has been around for years in motorsport racing but I think now they're trying to push it to everyone because how many people do you know that regularly check their tire pressure in their everyday driver and in that case it is probably a way just to make an extra few bucks. My .02
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I don't think anywhere it says you never have to check your pressure again...that would probably be too much chance for a lawsuit! 
