<VV> Tire size vs air pressure survey/better late than never

[hallgrenn at aol.com]

2 cents worth.  After checking my tire books and double checking the current tires on my cars (Corvair and non-Corvair) my understanding is that the maximum pressure is at the maximum rated tire load.  (I know some of you inflate your tires to the highest PSI for your own reasons and like it, but I won't criticize your decisions)  None of my cars have tires with loads approaching the maximum rated single tire load and consequently the vehicle manufacturers (in this case GM) specify a lower PSI.  Our Corvairs came with a recommended pressure differential of 12 to 15 pounds front to rear (in the owner's guide that came in the glove box--why it changed year to year is unknown to me ).  The front tires will not have all of their tread on the road if they are inflated to the typical 30-35 PSI.  

In over 140,000 miles in my factory quick steering F41 equipped LM I never had any flex of the frame at the box.  If I ever experience that problem I will look first at my steering geometry and then the tires.  The largest size I've run is 205 with no problems.  This is based on almost 400K miles in my Corvairs.  And I still love the handling and wish I could drive on everyday again.

I'll stick to 20-22 PSI  front and 30-32 rear--it's worked for me (and my tires) for decades.

And yes, my Greenbrier runs 35 and 35.

Bob Hall
CORSA
Group Corvair
Corvanatics