I have driven the Long Island beaches for many years I've had truck campers and now a 31 ft. 5th wheel. I air down both truck and camper tires to 20 PSI and occasionally 15psi. If you don't air down you will get stuck! Period! I believe your question is if a particular brand of tire will get enough "side wall bulge" to ride on top of the sand. The answer is; if you let enough air out it will. The best tire for the beach will not be the best tire for the highway. You will not ever get a tire manufacture to ok this practice. The flexing of the side wall at low PSI cannot be good for the longevity of the tire. Any compromise of the sidewall will not show itself on the beach, but will at 65mph on the L.I.E.