Thanks for the info. I will probably try 20 psi. I dissagree about only on sand. I find that I get a better grip on rocks and am less susceptable to sidewall damage because the tire will give more. You do, however loose an inch or so of ground clearance. Wheel damage might be a problem. On washboard roads the softer tire gives a smoother ride and it seems easier to find the speed that smoothes out the washboard.