Sorry if this is a stupid question, but a friend suggested that nitrogen is more temperature stable than plain air. His theory is that a tire inflated with nitrogen will not gain as much pressure when they heat up during use.

Has anyone on this board heard of using nitrogen in performance driving?

Scott

 

it is 'quite' common.

Costco in MD. has this method of filling tires as an option (green valve stem caps).

 

I've heard of it before too but heres a quote from Henry A. Watts in his book "The Secrets of Solo Racing":

<U>Nitrogen in Tires?</U> "Nitrogen, like all gasses, follows the ideal gas law, which states that temperature and pressure (given a constant volume) are directly proportional.

So, if nitrogen gets hot, it <U>will</U> expand. Since it has about the same specific heat as oxygen, it <U>will</U> get as hot.

Air is about 80% nitrogen in any case.

Nitrogen is also extremely inconvenient to carry around."

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cbstd &raquo;</TD></TR><TR><TD CLASS="quote">Sorry if this is a stupid question, but a friend suggested that nitrogen is more temperature stable than plain air. His theory is that a tire inflated with nitrogen will not gain as much pressure when they heat up during use.
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The only reason to use pure nitrogen is to get dry air. Humidity in shop air WILL expand faster than dry air. But not much.

 

".....blah, blah, blah......Nitrogen....blah, blah, blah"

Commercial Nitrogen - "Dry Nitrogen" - has minimal water / water vapor, unlike the air in the typical compressor.

We're talking about the increase in pressure that comes from heating that water from liqued to gas state.

If you've got moisture in the tires, let the "air" out, and replace with Nitrogen, you've effected some improvement in the situation, but ideally you'd "dry" the mounted tires using a an apparatus you can buy from a race shop, and then fill with Nitrogen. Or you could use Nitrogen to fill and purge repetitively.

Depending on how much water we're actually talking about you're doing this for about 1-2 psi based on the data I've seen.

Scott, who thinks that between this kind of ****, screwing with the car on the scales all weekend, and analyzing data plots I'd be looking for a new hobby where the majority of time was spent actually doing the activity itself. Or, in other words, just drive the ******* car. Sounds funny hearing myself say that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Willard &raquo;</TD></TR><TR><TD CLASS="quote">it is 'quite' common.

Costco in MD. has this method of filling tires as an option (green valve stem caps).</TD></TR></TABLE>

A Free option, actually (At least it is in Birmingham). I run nitrogen in my street tires just because it is free from them.

 

^What he said^

Charlie Sabb (5th Ave) says their stupid, he would charge about $5 a tire if someone asked because the machine cost him about a few grand, but I'm not complaining about the free stuff

 

If Nitrogen is readily available, then yea go for it. Like already stated the thing you dont want it moisture in the air which you will get plenty of if you use a compressor at a gas station.

 

I run N2 in my race tires for the reasons stated: dryness and pressure stability. The cost is the price of the regulator from a local welding supply company (about $100) and $18 per bottle of gas, which lasts half a season.

I recognize that it may only make a difference of 2-4 PSI over the entire heat range of the tire, but when when you ultimately have the car setup "right" that 2psi can make a hellacious difference in handling between the first and tenth lap.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Or, in other words, just drive the ******* car. Sounds funny hearing myself say that.</TD></TR></TABLE>

Who are you and what did you do with Scott?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greg Amy &raquo;</TD></TR><TR><TD CLASS="quote">I run N2 in my race tires for the reasons stated: dryness and pressure stability.</TD></TR></TABLE>

One in the same, no?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by siisgood00 &raquo;</TD></TR><TR><TD CLASS="quote">If Nitrogen is readily available, then yea go for it. Like already stated the thing you dont want it moisture in the air which you will get plenty of if you use a compressor at a gas station.</TD></TR></TABLE>

Fill your tires with Helium. It's also dry, as close to an 'ideal' gas as you can get, and you'll shave 40-50 grams off of your curb weight.



Just kidding. Just don't fill your tires in the rain.

 

Nitrogen filled tires seem to run smoother than just normal compressed air. It may be due to being heavier than air and acting as an extra damper. If it is heavier there would definitely be less air escaping and pressure loss.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Scott, who thinks that between this kind of ****, screwing with the car on the scales all weekend, and analyzing data plots I'd be looking for a new hobby where the majority of time was spent actually doing the activity itself. Or, in other words, just drive the ******* car. Sounds funny hearing myself say that.</TD></TR></TABLE>

It's funny you'd respond here.... because I was just thinking about you this morning.

I saw a dump truck and it had a giant rear anti-roll bar. Must've been at least 2 inchs thick. I looked at it and thought "****, somebody broke in to Scott's garage!"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">Fill your tires with Helium. It's also dry, as close to an 'ideal' gas as you can get, and you'll shave 40-50 grams off of your curb weight.
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Actually, you want a gas that doesn't act 'Ideal'. The Ideal gas law applies to Ideal gases. An Ideal gas is a point mass (Mass that doesn't take up space) Since all gas molecules take up space, there is no such thing as an Ideal gas, however real gases follow the Ideal gas law for the most part. However, some gases follow it better then others. You want to find a gas that is readily availible and does not expand as rapidly as an ideal gas.

 

I have friends who tried nitrogen in the tires and it inflates as much as plain air.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Willard &raquo;</TD></TR><TR><TD CLASS="quote">it is 'quite' common.

Costco in MD. has this method of filling tires as an option (green valve stem caps).</TD></TR></TABLE>

All Costcos in OR (and I'm told nationwide) have switched to exclusively Nitrogen in their tire shops. They're not suposed to let you air up with it unless you bought your tires from them.

I have a friend that works in the local Costco tire dept. and I talked him into purging and filling my race tires with nitrogen (he's also letting me fill my portable air tank when I need it) I figured I'd try it since it's free.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by msmotorsports &raquo;</TD></TR><TR><TD CLASS="quote">Nitrogen filled tires seem to run smoother than just normal compressed air. It may be due to being heavier than air and acting as an extra damper. If it is heavier there would definitely be less air escaping and pressure loss.</TD></TR></TABLE>

You do know that air is 70% nitrogen, don't you? And that the difference between a cubic foot of air and a cubic foot of nitrogen is less than a tenth of a tenth of a pound?!?