No more air in tires

[RickM]

Not sure if this has already been discussed or not, but here goes..

someone finally figured out that race cars use nitrogen in their tires, because it does not expand and contract with heat like compressed air does.

I noticed at our local Cocsto Warehouse that the tire shop now has a nitrogen generator, and they fill your tires with nitrogen, instead of air.

Someone told me that some other tire dealers are doing this same thing, but I don't remember who the others are besides Costco.

Anyone else filling their tires with nitrogen?

 

[jgp1843]

Nitrogen is used in race tires to limit pressure changes due to heat buildup. Compressed air always has some water vapor in it, and as race tires commonly operate at temperatures over 200 degrees, the water vapor changes to steam and expands, increasing the tire pressure significantly, upsetting handling. Since Indy car drivers can feel handling changes due to pressure differences as small as 1/10 PSI, this was a big deal. I think this trick was first used by the Penske team back in the '70s. I'm not sure of the real value of nitrogen in a street tire, unless it helps stop corrosion of the wheel and increases the life of the rubber. Anybody know?

The Penske guys are always coming up with interesting ideas. Back in the early '70s when they were running the Porsche 917-30 in the CanAm series, the car had a tubular space frome. They installed a tire pressure valve on the frame and pressurized it so they could check for frame cracks by checking the pressure.

 

[Eddo]

Just another gimmick for every day driver. Been long discussed about everywhere else on the web too.

http://www.cartalk.com/content/columns/Archive/1997/September/05.html
http://hybridcars.about.com/od/hybridcarfaq/f/NitrogenInTires.htm

 

[hyde]

It says on one of the above that 12% won't make that much of a difference, but does not mention anything about cold/hot pressure changes.. I suffer from that since temp drop and increase rapidly overnight in NYC.

 

[JeepJeepster]

If i ever get ahold of some nitrogen I really want to give it a try. No way am I going to spend $100 on it though!! :-s

 

[RickM]

Without trying to get into the physics or chemistry of compressed air, I know a few things about compressed air and nitrogen.

I've been driving for over 40 years now, and every since I started driving, I've always heard that you should check your tire pressure when the tires were cold, before you drive the car.

Someone stated above that race car tires operate at over 200 degrees. I wonder what my tire temperatures were this past summer when it was 112 or 113 degrees outside and I was driving down the freeway at 70 Mph or so? I'd guess they were pretty hot.

Compressed air does not always have to have a lot of moisture in it. I worked in diesel power plants for more than 20 years. Most of those big diesel engies used compressed air for engine starting. It was our practice to drain the water/moisture out of the compressed air tanks 3 times a day, once per work shift. I'm not sure what your local tire shop or mechanic does, but they would be wise to drain their air tanks of moisture/water at least once per day. I'm not sure of the moisture content of compressed air, but as stated, it does have some.

I now work in the broadcast industry. We keep our antennas and feedlines compressed at a low pressure to keep water out of them during rain storms. Some folks use nitrogen to do fill their feedlines and antennas, and others, like myself use dehydrators. A dehydrator is an air compressor that sends the air through a dessicant to try out any moisture in it. The moisture content in the air out of the dehydrator is extremely low.

I think the guy from About.Com missed the point entirely. He seemed to think that filling your tires with nitrogen would not effect your fuel mileage. He's probably right, you wouldn't notice any difference.

Please note that the second article was written 9 years ago. Maybe they did charge $100 for that in 1997, I don't know.

As I mentioned in my original post, Costco is now filling car tires with nitrogen. They have a nitrogen generator and a large compressed nitrogen tank. They are doing that for free, and they are doing it now. I noticed that when I went there to have a flat fixed recently.

If it's true that nitrogen expands and contracts less than air does, why not use it? We all have been told by auto and tire manufacturers that correct tire pressure will help with fuel mileage and with tire wear.

When I was in the military and working on aircraft arressting systems in the Air Force, we used nitrogen to keep a static pressure on our arresting system brakes. Guess what? We used "oil pumped" nitrogen, because it has less moisture content in it than regular compressed nitrogen. You can tell the "oil pumped" nitrogen by the number of black bands around the nitrogen tank.

I'm going to buy a set of BF Goodrich Long Trails at Costco next week for my Liberty. I'll let you know how the nitrogen works out. lol3.gif

 

[2003KJ]

Bought my Revo's at Costco a year ago and they filled it with Nitrogen. Note to any buyers, they automatically fill them at 33psi, and I find that i get better milage at 35psi. All you gotta do is ask them to put a couple more pounds in there and they'll be happy to do it.

Having been running with Nitrogen for a year now I really don't have much bad to say about it. I check my tire pressures once every couple of weeks, and I hardly have to top them off (and you can use regular air when you do have to top them off).

I recommend it!