I ride mostly in rocky conditions (uwarrie, NC & Brown Mountain Chester,sc). I'm riding 100/100 (will be swtching to 110/100 when warn out) Dunlop 756. The KDX Manual suggests running the tires at 14 psi in rocky conditions, but several of my riding buddies suggest 20 psi. At this psi and when it rains, the clay material among the rocks become very slippery. 20 PSI doesn't lend itself to great traction on clay or slippery rocks. IS 20 psi really needed to prevent tire/rim damage?