That's why they recommend those pressures, to decrease tire wear.
Also if the pressures were lowered too much and the tire carcass overheated and delaminated, they could be sued. So they err on the safe side.
The lower the pressures, the more the carcass flexes and conforms to the road surface. Great for traction, but that flex adds heat to the tire.
Track-only tires use materials and compounds that require that heat buildup (nylon carcass, less silica) while street tires do not (rayon carcass, more silica in compound).
That's the fallacy of using track/race tires on the street.
They never stay at required operating temp and degrade quicker than on the track.
For track use, you should see around 5-7 PSI difference between cold and hot pressures.
Too much pressure increase - the pressure is too low, too little increase - the pressure is too high.
For average street use, I often run around 35 PSI on the front and 38 PSI on the rear.
It's a compromise of traction and heat buildup.
If I was planning to have extended freeway riding, I would increase the pressure so the tire would run cooler, around 36 PSI for front and 39 to 40 for rear.
Last edited by SubSailor; 10-29-2010 at 01:40 PM.