I'm running 31x10.5's and usually run them around 6-8PSI and have very good luck with that. This last really deep snow we got, 8PSI semed to work nicely
When I bump up to my new 33 TSL's I'll be letting ALL of the air out of them and driving around the yard for a few days to help break in the sidewalls. Took about a week with the 31's doing that before the sidewalls really started to flex.