The Picture says it all, I parked on top of the dune waiting for the Jeep Wrangler and Land Rover Defender to winch the Ford Exploder....Explorer (sorry) out of a bowl.
The picture is when I had the 265 tires, I had to deflate down to 10 PSI to really get a grip, but in your case 14-15 is ok. I now have installed 285s. the 265s did ok if you are a frequent offroader but if you go on soft sand more often (every week like me) than the 285 are much more better.
SledgeHummer