well, did try out the MT/Rs on the 80 in the sand dunes at SnT. Relatively light cruiser. I was happy to see that -contrary to what I had read in several places- the MT/Rs behaved very nicely in the sand. Did not get stuck once. I did not get the impression that they were digging in excessively. Of course, you gotta stop pushing when you bog down, but they were not touchy at all. Did most of the dunes playing with 15 psi and it went anywhere I wanted including some steep slopes with no difficulty due to the tires. Out of curiosity, I also set them to 40 psi and went back in (at night so not quite as extensively). I could tell that it was a bit harder to go up dunes and I did dig in a bit easier, but I still was able to go just about anywhere I wanted as well. My conclusion: for plain sand running -meaning no fooling around on purpose with big dunes- I would not even air down at first, and if airing down would not go down to 15 psi unless getting stuck repeatedly.