I presently have 12x20 inch wheels and 325/60/20's on my truck. I am considering going back to my stock 20 inch wheels an am trying to determine just what tire I can run on the stock wheels which I believe ar 8 inches wide. Want to maintain the current height but possibly reduce the width.
Plan to puchase the BF Goodrich AT's with an "E" load rating.
Bottom line is I want to maintain at least the same height and reduce width.
Any feedback is appreciated.

 

something along the lines of LT295/70 is probably about it.

I would suggest going to a tire place and seeing what is there and do some measurements.

8" rim width is what I have on my stock 18" rims.

 

OE on that truck with 20's is:
LT275/65R20

The BF Goodrich is:

Size:
LT275/65R20E1 126R W