Did you know?

[Slant]

...that they use nitrogen in race car tires? I just thought it was interesting.
http://www.howstuffworks.com/question594.htm

[Bling]

I did. Too much Speedvision.

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Barry
Super White 6speed
Injen CAI
TRD Exhaust
B&M SS

[vvtlikick]

On a similar note, in as old SCC, they recieved a reader letter from someone who had used helium in street car tires (to save weight! <IMG SRC="http://www.newcelica.org/ubb/smilies/cwm27.gif" border=0>). SCC did some simple math, and figured you could save approximately 0.25 lb per tire by switching from air to helium.

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[GTS LAID]

do you know what would happen if you hit a nail going at 50 mph in 32psi of helium... hehe.. . you wouldnt be laughing thats for sure..

[vvtlikick]

Originally posted by GTS LAID:
do you know what would happen if you hit a nail going at 50 mph in 32psi of helium... hehe.. . you wouldnt be laughing thats for sure.. Are you thinking explosion? Because it's hydrogen that is the highly explosive and dangerous "H"-gas.

Hey....wait a minute. Hydrogen is lighter than helium, so maybe it's a good idea to fill the tires with it <IMG SRC="http://www.newcelica.org/ubb/smilies/cwm27.gif" border=0>.

[cbr600drm]

It is much more stable. It prevents the tire pressure from changing as the tires heat up and cool down. It is neat isn't it.

[GTS LAID]

Helium has 2 electrons in the outer shell (and total).. it is very stable (part of noble gases in periodic table)... it wouldnt explode from the pressure.. but there are some problems with it.. heres a list:

I think there are a number of factors that would have to be examined and
tested thoroughly.

First, the concept of the size of a rare gas, i.e. He, Ne, Ar, Kr, Xe becomes itself a little squishy and depends upon what the experimental criteria are. The classical Van der Waals constant 'b' in the eq. of state (V+a/V^2)*(V-b)=nRT is probably as self consistent as any other criterion, yet the value of 'b' is: 0.02370, 0.01709, 0.03219, 0.03978, 0.05105 cubic liters, respectively. Look He is LARGER than Ne!!! This has to do with the shielding, or lack of, in the 2S state of Ne with 10 protons vs. only 2 for He in the 1S state, but nonetheless, it's a surprise.

Second, helium diffuses very rapidly through rubbery materials -- the cause of the short life of helium filled latex party balloons. Aluminized Mylar is much better. But this could be a problem if tires kept "going flat".

Third, helium diffuses readily into some metals. This could be important, if it causes embrittlment.

Fourth, a subject about which I know nothing, but what about acoustic effects?

The thing i was talking about with the nail.. is that if its hit with a nick then it'll diffuse slowly and you wont be able to readily replace it...

[vvtlikick]

Originally posted by GTS LAID
Helium has 2 electrons in the outer shell (and total).. it is very stable (part of noble gases in periodic table)... it wouldnt explode from the pressure.. but there are some problems with it.. heres a list:

I think there are a number of factors that would have to be examined and
tested thoroughly.

First, the concept of the size of a rare gas, i.e. He, Ne, Ar, Kr, Xe becomes itself a little squishy and depends upon what the experimental criteria are. The classical Van der Waals constant 'b' in the eq. of state (V+a/V^2)*(V-b)=nRT is probably as self consistent as any other criterion, yet the value of 'b' is: 0.02370, 0.01709, 0.03219, 0.03978, 0.05105 cubic liters, respectively. Look He is LARGER than Ne!!! This has to do with the shielding, or lack of, in the 2S state of Ne with 10 protons vs. only 2 for He in the 1S state, but nonetheless, it's a surprise.

Second, helium diffuses very rapidly through rubbery materials -- the cause of the short life of helium filled latex party balloons. Aluminized Mylar is much better. But this could be a problem if tires kept "going flat".

Third, helium diffuses readily into some metals. This could be important, if it causes embrittlment.

Fourth, a subject about which I know nothing, but what about acoustic effects?

The thing i was talking about with the nail.. is that if its hit with a nick then it'll diffuse slowly and you wont be able to readily replace it... Okay, already. :tired I realize you're not so dumb as to confuse Helium with Hydrogen. ;)

And in SCC, I think they mentioned that the tire would lose helium pressure due to it diffusing through the tire. Don't know about other issues with helium inflation.

Anyway, don't worry about me...Regular old atmospheric blend is good enough for my tires. :D

[GTS LAID]

you can use nitrogen.. However heres an interesting scenario... With the wheel hop that our fwd cars sometimes experience we can have major resonance in the tire core...

How would you like to hear a sonic boom (really) every time you dropped your clutch

[pitcrew]

Helium (If I remember my chemistry) has a much higher coeffient of expansion than air or nitrogen (air is mostly nitrogen). The reason that they use nitrogen in Nascar tires is to stabilize the expansion/increase in pressure by not introducing any water vapor into the tire, (compressed nitrogen is completely free of water) which turns to steam at racing temps, and since the amount of water vapor in air is not constant, the change in pressure is not constant. With 1# of pressure change affecting handling, the crew chief needs to know how much pressure increase will happen in the course of the race.