"Chalo" wrote: (clip) The lower the pressure, the easier it will be for
you. Every little bit helps a /lot/. (clip)
^^^^^^^^^^^^^^^^
By lowering the pressure, you are causing the tire to bulge to a width which
would not fit between the chainstays or fork, but, since the wide part stays
at the bottom, you can get away with it.

As Chalo says, on sand, pinch flats are not a problem. And also. since
traction is so poor, the side forces on the bead are not likely to pull the
tire off the rim. You will probably find that it is best to run the tires
almost flat. (Don't forget to add air if you leave the sand, though.)