nitrogen

[Cloaked]

I was contacted by my tire guy, he told me that my "Michelin Pilot Sport Cups" had arrived. He asked me if I wanted to fill them with nitrogen, thinking about it, it doesn't seem like a bad idea. but what is the correct tire pressure when using 18" all around ?

[gasboy]

you won't be far off with 30 psi.
i'm not sure that nitrogen isn't just another profit center for tire shops that bought "nitrogen generators".mabye it has a place in nextel cup,f1,ect.but isn't the air we breathe already 78% nitrogen?

[Cloaked]

Originally Posted by gasboy

you won't be far off with 30 psi.
i'm not sure that nitrogen isn't just another profit center for tire shops that bought "nitrogen generators".mabye it has a place in nextel cup,f1,ect.but isn't the air we breathe already 78% nitrogen?

I was thinking that it wouldn't be a bad idea if you're not required to come after a track session and bleed air out of the tires. I also thinking that when you store your track tires for a month or so you don't have to deal with the pressure dropping off greatly if at all, not to mention you can if necessary top nitrogen filled tires with air.

[DJWorm]

Filling tires with 100% Nitrogen as opposed to air which is 78% Nitrogen has 3 advantages:
1. Is more stable to temperature change. IE as the tire heats up the pressure does not increase as much.
2. Has a much lower water vapor partial pressure. again which helps the temperature/pressure stability.
3. As it is a larger molecule, will not leak thru the pores of the tire as fast as the Oxygen (21%) in air.

Some side benefits might be:
1. Less corrosion
2. Lower tire operating temperature
3. Increased mileage, both in fuel usage and and tire wear.

It is advantageous for tracked cars in which tire pressure changes are more critical. Also there is less bleeding back to cold between runs.

The caveat is that racers must then refill with Nitrogen to maintain this slight advantage. Thus they must carry bottled Nitrogen in their trailers or tow vehicles.

As a side note "Hoosier" Tom uses 2 huge Dessicant Driers on his Compressor air line at the track and AutoX events. As he is filling so many tires...Nitrogen would be cost prohibitive....so he uses the next best thing.....REALLY, REALLY dry air.

As to the side benefits:
-The better gas milage and tire wear are probably due to the fact that Nitrogen inflated tires tend NOT to be under inflated as much or as long.
-This would also tend to allow them to run at the correct pressures and avoid high temperatures.
- The corrosion aspect has become more critical with the use if tire pressure monitioring systems and automatic tire bleeding systems used by some racers to maintain a constant pressure. A drier gas means a cleaner less corrosive environment for correct operation.
- IF a racer runs Magnesium wheels he wants to run the driest gas available as corrosion will turn Magnesium into a white powder.

I retrospect:
- I DO run Nitrogen in my race tiresand wheels.
- I run very DRY air in my family street vehicles.
- However I have switched to Nitrogen in my tow vehicle tires that see high mileage (249,000, presently). With air I was getting 30,000 miles per tire, rotating every 3,000 miles and checking pressure weekly. I am now getting 40,000 miles with Nitrogen in the tires and probably 1-2 MPG better gas milage.

[HONDAFIXER]

This is Honda's opinion
Surf any automobile tire-related website these
days, and you’ll likely see something mentioned
about nitrogen inflation. It’s becoming a hot topic.
We’ve gotten a number of inquiries lately
concerning American Honda’s position on this
practice.
When it comes to inflating automobile tires, it’s
our position that ordinary, dry compressed air—
which is about 80 percent nitrogen already—is
the best choice. That’s because it’s more readily
available, and the benefits of using nitrogen
simply don’t appear to outweigh those of using
compressed air.
The practice of inflating tires with nitrogen really
isn’t anything new; it’s been around a long time.
It’s been commonly used on aerospace vehicles,
commercial and military aircraft, military vehicles,
race cars, and even heavy off-road construction
equipment. Here’s why:
• To meet rigid safety and performance specs,
the required tire inflation pressures are often
very high, especially in the aerospace industry.
The tire inflation pressure for NASA’s space
shuttle, for instance, is a whopping 315 psi!
• Nitrogen is an inert gas; it doesn’t combust or
oxidize.
• The process used to compress nitrogen
excludes water vapor. Water vapor can expand
if the temperature climbs above 212°F.
• Tires inflated with nitrogen leak slower over
time than those inflated with compressed air.
Automobile tires, on the other hand, are subjected
to an entirely different set of conditions. Here’s
why inflating tires with nitrogen offers no real
advantages:
• Although tires inflated with nitrogen leak
slower over time than those inflated with
compressed air, they still leak and need to be
reinflated to maintain proper pressure. If you
can’t find a place that offers nitrogen
inflation—and there aren’t yet all that many
places that do—your only option left is to
reinflate with compressed air. Doing that
drops the nitrogen purity.
• Nitrogen offers no better protection against
road hazards such as cuts and punctures. So
no matter what you inflate the tire with, you
still need to check the condition and pressure
of the tires at least once a month as
recommended in the O/M.
• Tires that are inflated with compressed air and
properly maintained offer the same fuel
economy, tread wear, and ride comfort as
those inflated with nitrogen.
• Nitrogen for automobile tires is produced by
nitrogen generators, which typically get about
95 percent purity. But to actually get that
level of purity into an automobile tire, you
would have to deflate and inflate that tire with
nitrogen several times. If you’re not careful
doing this repeated deflation and inflation
process, the purity level winds up being closer
to 90 percent (compared to the approximate
80 percent nitrogen already in compressed
air). Because of this, those claims of less
pressure loss with nitrogen aren’t valid.
So here’s the bottom line: Nitrogen is an ideal gas
for inflating tires in aircraft, military vehicles, race
cars, and heavy off-road equipment, but when it
comes to automobile tires, it offers no apparent
advantages over ordinary, dry compressed air.
Our advice to you: Just stick with the air you
breathe.

[2MchFun]

If we fill our tires with Helium will it make our cars lighter (thus faster)?

[wvphoto]

siska just puts his lips on the inflator valve.. and blows..

thus.. hot air in his tires..

You are a nasty boy...!

[Cloaked]

So if I use nitrogen for my track tires only it would seem that there is the benefits that could help in the short and long run, Thanks.

[Olitho]

I have a few opinions about using nitrogen at the track.
1. It is great to have that big tank of gas for adjusting tire pressures. There is no air compressor to worry about firing up. I can even drive an impact driver if need be.
2. All is for naught if whoever changes your tire gets even some of that tire mounting lubricant inside the tire. That added moisture is going to ruin the benefit of the nitrogen. There are dry tire lubricants available.
3. Even with bleeding my tires out I find I get pretty darn near as much pressure increase when the tires heat up as with regular air. It is slightly less, I have not done an accurate study, but my tires seem to maybe only go up 8 psi vs. 10 or 11.

That has been my experience. I do carry a big nitrogen tank and it is better, but not by much....


Fastest regards,

Oli

[gasboy]

I retrospect:
- I DO run Nitrogen in my race tiresand wheels.
- I run very DRY air in my family street vehicles.
- However I have switched to Nitrogen in my tow vehicle tires that see high mileage (249,000, presently). With air I was getting 30,000 miles per tire, rotating every 3,000 miles and checking pressure weekly. I am now getting 40,000 miles with Nitrogen in the tires and probably 1-2 MPG better gas milage.[/quote]

djworm i usually like your posts but....
how in the world does putting nitrogen in your truck tires add 33% to your tread life?! you were rotating them and checking pressure regularly already.as for 1 or 2 mpg increase(which is probably 10 to 20 percent on a tow rig) i say YEAH,RIGHT! sure it does.tire pressure will still need to be bled off during race day,just not as much.

[RocketSled]

Nitrogen fills do one major thing for performance... Compressed Nitrogen is dehumidified, there is very little water vapor. Water vapor pressure changes more rapidly with temperature than a pure gas. Nitrogen's advantage isn't so much that it's Nitrogen, but that it's made with a very minimal amount of water vapor. NASCAR likes it because it's more predictable over temperature ranges than a random charge of outside air.

Nitrogen also conducts heat better than atmospheric air. Nitrogen filled tires run a little cooler because the gas dissipates heat more efficiently.

Most people think that a tire is perfectly air tight. It isn't. Gas gets out around the bead, through the valve stem, and even through the body of the tire itself. Anyplace there is rubber, and maybe some places where there isn't (Castings can have small voids that allow gas to escape).

Passenger cars benefit more from the fact that Nitrogen leaks more slowly than regular air. If you're not smart enough to check your tire pressures on a regular basis, Nitrogen increases the period of time you have before you need to remember to do it.

Also, Wheels can be corroded over time by the moisture in regular air. Nitrogen has little if any moisture so it reduces the risk of corrosion.

For guys like most us, who check tire pressures regularly and probably put new rubber on the wheels every 10K miles or so, Nitrogen provides no real benefit to daily driving. Arguably, it's more trouble than it's worth since you need a ready supply of Nitrogen to top up and Nitrogen filling stations aren't very common. I'm fine with the pancake compressor in my garage, thank you!

[speedpup]

you also need to fill and evacuate 3-4 times to remove most of the air in there. I bet most shops just do one fill and they are done.