tire pressure depends A LOT on tire size, side wall stiffness and sand texture. I have run down to 6 psi on sand but i was also running bead locks so i didn't have to really worry about rolling a tire off the bead. The stiffer the sidewall the more air you can let out and not worry about rolling the bead off also. And if your on hard packed/wet sand you can run the pressure slightly higher because you generally dont need quite as much of a footprint to get traction. I have a dune trip coming up in 1 1/2 months (going up to Silver Lake Dunes in Michigan again). And I ordered another set of rear wheels and paddle tires. If you going to be in sand quite a bit the paddles sure do help a BUNCH over normal dirt tires. I plan to start out my pressure at 10-8 PSI and I will see what the sand conditions dictate the pressure needs to be. Also I will be on 14" wheels this year where as in the past I have been on 12" wheels so that will make a difference with pressures also.