[DeTomaso] Tires, Tire Life, and Nitrogen

[JDeRyke at aol.com]

According to real-racers, nitrogen is used because its bone-dry, not because 
of the molecular size. Nitrogen is also chemically inert to rubber while 
compressed air contains 20+% oxygen which reacts with various ingredients in the 
compounds. Compressed air also contains water vapor and this changes volume with 
temperature. The change causes inflation pressures to increase as tires get 
hot. Since a pro-racer can feel a 2-lb change in his tire pressure, automatic 
pressure increases only confuse tuning. 
And gases-leaking-through-the-sidewalls is one more reason why race tires 
don't work on the street. The sidewall rubber is so thin on some racing tires, 
I've sometimes been able to see the sidewall cord thru the skimpy rubber 
coating. There's no sidewall protection, and zero ozone protection to the carcass 
from that direction. Even M Schumacher likely curbs his street car's tires now 'n 
then! So unless you check pressures EVERY TIME you get the Pantera out of the 
garage, race tires won't be dependable for more than a few months, befitting 
their lowish price. 

In other news,   PIrelli has started up their long awaited Historic Tire 
Division, in a brand new plant in Turkey. I'm told that before too long, 
old-familiar high-speed-rated 15" tires WILL be available through some dealers (such as 
Pantera vendors) but none will be cheap! If you need cheap tires, Manny's 
Used Vintage Tires & Screen Door Sales are reasonable..... FWIW- J DeRyke



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