I got the Big Dog (2003 Chev Dmax ECLB) weighed today. Total weight: 7700 lbs. Front axle: 4380 lbs. Rear axle: 3320 lbs. That means each front tire carries 2190 lbs. and each rear carries 830 lbs. The Goodyear inflation table puts the fronts between 65 and 70 psi. The rears would be over-inflated at 35 lbs. How soft do I dare run the rears?