Nitrogen filled tires.

[ShelbyDogg]

Yeah,1. When he breaks the bead, he might get covered in GOO.
2.Maybe it has nitrous oxide in it, He'll start laughing, then forget what he was doing, then walk into traffic and get hit by a car?

 That Fix-a-flat can get you off of the street in dangerous situations, but it'll throw your balance off. So you need to get it cleaned out and flat repaired ASAP.

[Four-Forty-fied]

When I fill my tires, I like to use a mixture of about 80% nitrogen and 20% oxygen.

[Tropicalcats]

When I fill my tires, I like to use a mixture of about 80% nitrogen and 20% oxygen.

What's your reason for that?

[gomopar440]

When I was stationed at a Navy A6 Intruder squadron back in Alameda, CA, we used to fill the aircraft tires exclusively with Nitrogen. This was for a few reasons.

First of all, aircraft tires can be filled as high as 3000 psi. If you have a blowout there's an immediate high velocity release of air (including Oxygen) which could cause or fuel a fire being generated by hot brakes or leaking jet fuel (yes, they ALL leaked). If you don't think there's enough oxygen in there to make a difference, think about why Nitrous Oxide works. It also has a high pressure system that releases a shot of oxygenated fuel very quickly. This scenario isn't very applicable to our cars though as you would never get the tires to hold pressures anywhere near high enough for this to be a factor.

The second reason was basic chemistry. Nitrogen molocules are physically larger than regular compressed air molocules and are less likely to pass through the rubber tires. Car tires that have sat for a long time with regular air in them can eventually go flat if just left without being checked and maintained. With Nitrogen in the tires, they can be left far longer with no or at least very little loss of air pressure as long as it is a sound tire.

The other reason had to do with pressure changes due to heat. When a tire is heated up from use, Nitrogen does not expand as much as regular air when in a tire. This means your tire pressure will remain stable through a wider range of temperatures that regular air. This would be extremely important in an endurance race road course type of car. It would also make a difference say after a burnout right before doing a quick trip down a drag strip.

So basically, there are at least two very good reasons to use nitrogen to fill your tires. However, if you have to go WAAAY out of your way to find or use Nitrogen, and you don't race professionally, you'll be fine using regular air. Just be sure to stay on top of checking your tire pressures regularly.

[gomopar440]

I don't know what the gas ingredient in "fix-a-flat" is BUT once you use it the can comes with a WARNING sticker that you are suppose to put on the tire! to warn the tire changer that it has that ingredient in it!! because something dangerous can happen!! I was told that if the tire changer adds air to the tire something bad would happen!! just my 

Ever taken a lighter and a can of WD-40, hair spray or even that silly string stuff to make a flame thrower? The propellant in the can is highly flammable. When it's compressed in a tire like used Fix-a-Flat is, it's not just flammable, it's now EXPLOSIVE! If the mechanic creates a spark while dismounting the "Fixed" tire he can cause an explosion and injure or even kill themselves and anyone else standing nearby. That's the main reason for the warning sticker. I'd also verbally tell the mechanic about it if I brought a tire like that in just to be doubly safe.

[Plum6Pak]

When I fill my tires, I like to use a mixture of about 80% nitrogen and 20% oxygen.

LMAO!!! Good one four-forty-fied. 
He just said he uses plain ole air.

About 1% of other rare gases make up the rest of our atpmosphere but they are a very minor part of the air we breath. Argon .934%, CO2 .035%, Neon, Helium, Krypton, Hydrogen and Xenon make up the other .031%. For instance, in one million cubic feet or parts per million of air, only .5 ppm is hydrogen, .087 ppm is Xenon. 

If the people who are selling you the N2 for your tires tell you to quickly get the tire re filled with nitrogen if you added air or you'll have problems, they are just trying to sell you more nitrogen. As already stated there is a small difference in expansion rates but till you can get the N2 back in your tire, go to the gas station and air up your tire, it will be okay, just don't do this on your F-16.   

You're breathing 80% N2 right now but remember you need the oxygen in each and every breath or you'll drop like a rock. Only one or two breaths in a completely inert atpmosphere and you're gone. Many people don't realize the asphixiation hazard there is with N2 and people die from it quite regularly. Too much oxygen= extreme fire hazard, too little= asphyxiation. If you are planning on using nitrogen for anything, please understand it before you use it. Not trying to show off but this is the line of work I am in and people die quite regularly from misusing oxygen and nitrogen as well as other gases. Please understand what you are doing before you attempt to use any of these bulk gases.
I have many bulk liquid nitrogen units at mines where they inflate the haulage truck tires with it, it prevents rot inside the tire and oxydization on the inside part of the rim. Saves them a lot of money in wheel and tire costs. And as gomopar440 stated, all the USAF bases use the N2. Just some safety information, hope it helps keep someone from getting hurt.

[MJS73]

Air is 80% nitrogen, anyway.

[purple1]

The biggest advantage to Nitrogen in tires is there is no mosture (H20). Plain old air always has some mosture. When the tire gets hot the mosture expands and increses tire presure. With pure nitrogen in the tires the presure will stay constant.

Dave