[Mrmerlin]

I took my FJ40 Landcruiser to Pismo beach , lots of fine grain sand, anyway i tried to go up a big hill and could make it up about half way, I had bigger/wider tires that had been aired down to 12 psi.
One of the regulars cam over and asked why i could not make it to the top, i told him i was losing traction, his suggestion air down to 2 psi, since I had a air compressor on board I figured OK why not, so i got my lo pressure tire gauge out and the valve stem remover and let out the air, the tires looked low but they were not flat.
Anyway i tried the hill again and i made it right up to the top like nothing, no drama it was almost easy.
That said if your getting stuck with 15 PSI try lowering the pressure , its amazing how much different the tires work with a lower air pressure.
Have an onboard compressor in your travel kit as well as a tire plug kit in case you pick up a nail