Door jam says 75psi, rode like a cement truck. 45 feels good but front tires look squished. Recommended pressures?

 

take a piece of chalk and put a 1 inch wide strip across the tread. slowly drive the truck around the block. when the chalk line is evenly wore off the proper pressure is in the tire.
inside wore off, but outside still there? too much pressure.
outside wore off but inside still there? not enough pressure.