[rickst29]

If you're concerned about bad "road" (ahem!) conditions down there, you might want to invest in a TPMS (Tire Pressure Monitor System). Catch any punctures and sudden pressure loss before huge damage occurs.

On my 2619, which we load very heavily, the correct pressure for the tire loading is usually less than 50 PSI. (In fact, the Goodyear Table recommendion usually works out to less than 45 PSI.) So although the class-D 15" tires are capable of 65 PSI, running rock-hard like that tends to shake the TM and contents more than you'll like.

It's also a bit of a safety issue, the contact patch with the ground is to small.

And I'll SWAG that maybe it's a bit of a tire issue too: Marathons are made to run with a certain amount of flex in the sidewalls, and driving gazillions of miles on "bad" roads with no flex and high pressure might not be good for the tires. Maybe WmTire can chime in-- does this SWAG make sense or am I blowing smoke (about the tires themselves)?

In any case, though, you're not gonna want 65 PSI for the two reasons I listed above. (Except maybe when crusing fast on smooth freeways.)