Golly - I run 45psi all around and have no problems - now I'm wondering if maybe I should run more...but even at that I still get full across contact. I don't put anything in it except my big you-know-what - so maybe that's why?
I used to run higher psi on earlier non-Dodge trucks - got better gas mileage but could feel a dime when I ran over it. I like the tires to soak up a little of the roughness...and I like full contact on a wet road.

 

Just be sure to check the wear on the outside edges of your tires. If you see them wearing faster than the centers, you are running too low. They should have a SLIGHT buldge to them, but it shouldn't be excessive.

Again, it all depends on YOUR truck, YOUR tires and YOUR driving habits.