I tow a travel trailer with my 94 F-350. The tires I have now are M+S LT285/75R16, load range D. On the sidewall it says max psi is 65 psi cold. According to the door jam, it says to air the tires to 60 psi front and 80 psi rear. I had it in one time and the mechanic aired the rears to 80 psi. Dangerous I'm guessing. Will E rated tires handle that much pressure? I know Ford recommends that pressure so I suppose it would be in my best interest to go that route. Any opinions?

 

Well, the 285's are not stock Ford size. Most likely 235x85R16's were. At 80psi, the 235's will carry 3042 pounds. Your 285's should be around 3300 pounds at 65psi. I'd run the rears at 60-65 psi, fronts 50-55 psi. The load range letter A B etc.. goes along with PSI ratings. C= 50psi, D=65psi, E=80psi. Weight capacity can vary by size.