Tires: Load range, stock rims, tire store

Question
I have a 2003 F250 4 X 4 reg cab. original tires LT265-75R16 load range E. i would like to put on LT285-75R16 Load D. A salesman at a leading tire store showed me that the carrying capacities are not far off. do you think i would have a problem with the D's

Answer
Vince,

The stock rims on your truck are 7" wide.  An LT285/75R16 requires a minimum of a 7 1/2" rim.  Using a rim that is too narrow will cause the tread face to arch and that results on a tire that is directionally unstable.  The vehicle will feel as if it isn't sure the direction it wants to go, and the vehicle will be sensitive to side winds.