Minimum Air pressure for 19.5 ??

[Capt Eddie]

I have a F 450 with 19.5 wheels. I am going to the beach on the 18th. What would be the lowest pressure that I could run with these tires on the sand. Not for long distance, just to a camp site. I have the Jeep for the other 60 miles.

 

[G35Vortec454]

Ive aired mine down to 12 psi over deep sand.