What Longbox55 said is what I've always been told since the 70s (my brother worked for Goodyear in late 70s early 80s).
Tire pressure listed on the tire is max pressure that the tire can safely be used at. The pressure you should run is what is given by vehical manufacture not tire sidewall max presure. I have a pamplet from goodyear I picked up a couple of years ago that also confirms this. I didn't meen to open a can of worms I just was wanting to know what Chevy said the psi should be. Granted it may not list radials but I can use it as a starting point.
