i have a question that i cant seem to find the answer to, if you are in an suv and youre going up a sand slope slow like 5miles per hour , up to a point the suv will slow down and the wheels start to slip, you can use momentum to go over i know, but say i was in 2 wheel drive vs 4 wheel drive, i can go up further using 4wd and if i lower the pressure i can go even further up the slope. how can one increase the friction on deep soft sand. wide tires or narrow ? tall tires or small ? high pressure or low ? my questions are strictly about going up a sand dune slow with no or as little wheel slip as possible.