If this is a Drag question, I have no idea. But for duning, I run my sand sharks at 6psi. In the sand, if you run them any lower, all you do is shoot a ridiculous roost, and don't gain any traction, I have found, with my particular tires. I have found that 6lbs in the dunes is that fine line between comfort (Hard tires = rough ride) and not pissing off everyone following you. I haven't noticed them "hooking up" any better at lower pressure, but that obviously will depend on the tire!