Isnt 40 Lb.s above tire markings , 40 lbs would be good for gas milage and top speed for short runs, the factory has tried all different preasures for best results , I go for factory ideas, it would be a little up or down in preasure for your own Wt. one guy a few years ago said it was good for him with 28 /32 with him alone, and with girl friend, he was 200 Lb.s