Tires: tire size, p255 70r16, tire size

Question
on 2001 F-150 can I install LT225/75R16. Now has P255/70R16

Answer
Steve,

 As far as overall diameter goes you shouldn't have any problems using the LT225/75R16.  However, a LT225/75R16 typically comes with  8 or 10 ply ratings and you will notice a difference in ride and handling.  

If you are towing anything you will have improved handling under a load contrarily, if you do not tow you will notice a stiffer ride and decreased cornering abilities.