2016 2500, 6.4L. LT 275/70/R18 . I know the door jam sticker says 60 psi front, 80 psi rear. But why ? Isn't the engine heavier over the front most of the time. (not loaded, not towing) If the back end is loaded down it seems like 80 makes sense, but even then...80 is the max cold psi on the...