New to off road travel with my 2008 Provan Tiger, camper built on a 4x4 chevy 3500HD)running on bridgestone dueler A/T LT 265 75R16 load rating E, at 10,000+gvw, runs great hwy 70psi front/80rear, but off road even small washboard rattles my teeth! Any suggestions on how much I dare pressure...