59 replies to this topic

[TreadZone]

As said before the key to nitrogen is that it's dry. If you use the compressed air to mount the tire you have introduced moisture into the tire that you then hope to remove by purging. When we supplied and serviced tires for World Challenge most of the front teams used Nitrogen. Most of the teams on the other end used regular air.
Nitrogen will also hold pressure better. I blew up a balloon with air and it was deflated in 3 days, I inflated a balloon with Nitrogen and it was still inflated 3 weeks later. It's just one of the little things and they add up.
Joe

[dstevens]

Using a purge for a nitrogen fill is so you can circulate the nitrogen through the tire, not to displace the compressed air that was used to mount the tire. The reason nitrogen holds pressure better is that a more consistent moisture content behaves more predictably. As the moisture heats and the air properties change it effects the pressure inside the what is basically a closed vessel, the tire. As stated many time already in the thread, moisture content and consistency is the key. And most of us will never know the difference as we won't have the cars or the chops to be able to tell.

[Sphinx]

For those using the TR Motorsports in the 25mm, does that have two valve stem holes, or just one?  I saw a fellow competitor's set and his had two.   Just had a set delivered, and they had one.

[Bad Rusty]

So if I generally start my tires at 24-26 to get them to 35-35lbs after puling in from the track, where would you guess I should start with Nitrogen?

[William Bonsell]

We have multiple sets of TR Motorsports 30 offset wheels and they all have dual valve stems. Didn't think there was a difference with the 25's....

[Todd Green]

4 sets of C1Ms 30mm all have dual valve stems. Looks like the last ones I ordered were on 7/29/13.

[philstireservice]

We have multiple sets of TR Motorsports 30 offset wheels and they all have dual valve stems. Didn't think there was a difference with the 25's....

The +25's are BMW wheels so they don't have the dual valves. 

[luckymiata76]

Nitrogen will also hold pressure better. I blew up a balloon with air and it was deflated in 3 days, I inflated a balloon with Nitrogen and it was still inflated 3 weeks later. It's just one of the little things and they add up.
Joe

Joe-Your experiment had a flaw somewhere. Gases effuse at a rate inversely proportional to their molecular mass. In other words, light gases leak through pores faster than heavier gases. Here's what each gas weighs:

-water vapor =18 g/mol

-nitrogen=28 g/mol

-oxygen=32 g/mol

 

As you can see, only water vapor would leak through the pores of your balloon quicker and I seriously doubt there was enough moisture in your balloon to make a significant difference. Air, which is 78% nitrogen and 21% oxygen has almost the same average mass of pure nitrogen.

 

Jeff

[Sphinx]

The +25's are BMW wheels so they don't have the dual valves. 

 

 

That explains it.  Though given our general desire for a wider track, I'm sure there's a good reason why folks are continuing to order 30's.  Can someone enlighten me?

[Bench Racer]

I'm sure there's a good reason why folks are continuing to order 30's.  Can someone enlighten me?

Use spacers for a tuning aid.

[LarryKing]

I put 32 pounds of air in my tires. Why don't they feel any heavier?

[Bench Racer]

I put 32 pounds of air in my tires. Why don't they feel any heavier?

Do you really want to go there^ ?    

[Bad Rusty]

I put 32 pounds of air in my tires. Why don't they feel any heavier?

Love it, but can someone actually tell me if there is a pressure increase difference between standard air from my compressor vs. filling with Nitrogen so I know where to start tires cold?

[Brian Linn]

What do the tire guys use to mount tires these days?  I remember they used to slop a bunch of soapy water on the bead.  So if that water is sealed in the tire, it seems like potential for varying moisture levels, even with nitrogen.  

[GT40Jim]

I had the honor and pleasure of working the Rolex with Starworks on their DP program. (I got to belt Rubens Barrichello in for qualifying!) Anyway... Our tire guy was Richie Vockings who worked at Mclaren F1 as a tire guy from 2003 thru 2009. I asked him what did Mclaren do for tires. He said that they had a fairly large machine that they would hook up to the tires with multiple hoses and purge them overnight with heated zero moisture content plain old air. He said they tried a few different gases and always went back to plain air. I also crewchiefed Kevin Lepages Nationwide car at Texas this past year and know that Goodyear uses a large air dryer for inflating tires. We only use nitrogen for topping up because its a convenient source of dry air. So that's two of the largest big budget series in the world that do not use nitrogen. The stiffness of a Miata sidewall relative to its wheelrate and vehicle mass means that it is far less sensitive to pressure changes than a cup car.

[Steve Scheifler]

What do the tire guys use to mount tires these days? I remember they used to slop a bunch of soapy water on the bead. So if that water is sealed in the tire, it seems like potential for varying moisture levels, even with nitrogen.

My guy has used liberal amounts of WD40 for decades, including all his own race tires for FA and other classes. I've wondered about it both in terms of what it might do to the rubber and whether it increases the risk of a tire rotating on the rim, but he swears by it and I've had no complaints.

[FTodaro]

Mark Bennett turned me on to P-80 it goes on wet but leaves no residue. perfect for tires and bushing.

 

http://www.ipcol.com/shopexd.asp?id=16

[Tom Sager]

Joe-Your experiment had a flaw somewhere. Gases effuse at a rate inversely proportional to their molecular mass. In other words, light gases leak through pores faster than heavier gases. Here's what each gas weighs:

-water vapor =18 g/mol

-nitrogen=28 g/mol

-oxygen=32 g/mol

 

As you can see, only water vapor would leak through the pores of your balloon quicker and I seriously doubt there was enough moisture in your balloon to make a significant difference. Air, which is 78% nitrogen and 21% oxygen has almost the same average mass of pure nitrogen.

 

Jeff

Do you work for the New England Patriots on weekends filling footballs with very moist air before games in a warm room?

[ChrisA]

I put 32 pounds of air in my tires. Why don't they feel any heavier?

That's a lot of unsprung weight to be carrying per corner. But if that's the way you like it....

[Todd Lamb]

"...eases installation of tight-fitting rubber parts by reducing the force needed for insertion."

 

Sounds like it might be useful for runoffs tech too.

 

 

Mark Bennett turned me on to P-80 it goes on wet but leaves no residue. perfect for tires and bushing.

 

http://www.ipcol.com/shopexd.asp?id=16