Just bought a set of Goodyear Wranglers deep tread for my 2003 Ford 4x4 Ranger. They are rated to take 80lb of tire pressure. Needed a HD 10 ply due to frequent travel on mine tailing roads here. What kind of pressure should I run for everyday unloaded travel? Currently have 60 lbs but never have run 10 plys "E" rated on a small light truck before..thanks.