He does not overinflate the tires.  Many people put too much air in the tires thinking the car will handle better.  Not necessarly true.  Many Vettes have too much air in them.  Our C3 generally were about 26 psi.  Not too much weight for the large tires.  Going to a wider tire actually requires less pressure, but from bias to radial calls for adding 3 psi, in general applications.  Tire type also makes a difference.  I am running 29 with 255/60 tires, and like it.  But I am also watching tread wear.   When it comes out of the body shop I am going to use a pyrometer to measure tred temp.  If it's even across the tread, pressure is good.  If it is higher in the center, too much air.  Cooler in the center, too little air.   Keep in mind this is after stright line cruising.   Corners can change things, so check againg after getting sporting.  You may want to consider a blend.  I may end up dropping pressure a bit.

 

If the tires are hotter on one side than the other, the alignment is out.  Start there and re-evaluate.

 

Hard overinflated tires won't flex as much and make the posi chatter a bit more, or if they slide cause a bit of howling and leave some rubber on the ground.

 

Tire flex is not a bad thing.  THe new very small sidewall tires do handle better on the track.  But on a rough surface pavement the tires may not conform to the pavement, and that causes them to slide across the pavement instead of grabbing.   The reason it works on many cars is the fact that the suspension is also designed for that type of tire.

 

So the tires, the suspension, the surface, all make a difference on what works.  I have no problem with Joels set up at all.  It works. 

 

Keep in mind, the air around you is already about 78% nitrogen.  So while there is an advantage, it's not as much as some would leave you to believe.  If you have a slight leakage, and need to refill the tires on a regular basis, It's probably not worth it.   In my daily driver, it's not worth it.  For our C3s, it could be a good choice.

 

So is nitrogen a good thing?  Yes.  Is it always worth it? No.  But sometimes it is.

 

Most of the guys I raced with , Ken, used dry compressed air. As you said, air is already 78% Nitrogen so it was hard to justify the added expense. Wouldn't a good moisture trap on an air compressor dry the air out adequately? That is what I use today. Of course we were just a bunch of amatuer road racers. I am sure the pro teams in NASCAR and SCCA probably use nitrogen. Since all gases obey the universal gas law, PV=nRT, how would nitrogen stabilize a tire over dry air? Since volume is constant, as temperture increases, pressure has to increase. Does it have something to do with the thermal conductivity properties of pure nitrogen vs. air?...just curious....

 

 

 

And the placard is missing on my car, and memory lets me down a bit on this one.   That's another reason I am considering dropping my pressures a bit more.   But thats after the dang thing is painted and back on the road.   By the way folks, with the correct pressure, they ride better as well.