Originally posted by m�¶bius:
Originally posted by gotapex:
Originally posted by weargle:
Originally posted by JCSVT:
At the last tracday I went to, alot guys were using nitrogen because the temp didn't change.


Of course the temperature changed. Have you ever even felt a tire after a track session? Why do you think that racers use pyrometers?
Nitrogen gives a predictable temperature change because it's dry and isn't influenced by water.


Yeah, it's a much smaller change. This is a huge deal with race tires. You get them too hot and they will start chunking.


I thought that was more for maintaining a proper tire contact patch? The rubber is going to heat up regardless as it's the main friction point between the track and car. I also use a digital pyrometer when I go to the track and the purpose of that is to gauge how flat the tire is going around the track. If the center is a lot higher than the edges then that generally means the tires have too much air (or the air has heated up more than anticipated which is where N2 comes in handy) and then I let some air out until the temps are about equal. You can tell a lot by tire temps.
I have never read nor seen anything pointing to the N2 keeping the rubber temperature down. I will have to look into that. I know Carroll Smith talks about using N2 in race tires in his books but I haven't actually picked up his books yet. They're definitely on my 'must read' list, though.
My two cents...



Contact patch is definitely part of it, but so is temperature itself. Most are made to operate very very well within a set range. You should hear those Ferrari F360 Challenge Stradale guys complain when they fail to check temp and it goes over 36 psi on the track. LOL.