Bad, long, washboard roads get my attention. To take the edge off, I'll air down from my pavement pressure of 65 PSI, all around, to 35 PSI, on my E-rated Nitto Ridge Grappler 285/75R16 10-ply tires, on my Cummins/Hawk combo (8,700 lbs split equally on both axles - the Cummins diesel is heavy...