Will these fit...?
 

will 315/70R17 or 305/65R17 bf goodrich all terrain fit on a 2003 f150 fx4 with stock suspension...and stock rims...

I have a 2003 Fx4, I had 305 65 16's on it I think, it was either 60 or 65 anyways I had to trim some plastic in the front and even then I couldn't turn the wheel all the way with out rubbing. As far as stock rims go I have no idea I am going to assume without a leveling kit it is going to rub.

The 315/70-17's (35x12.50) will fit using the OEM wheels, but you will have some minor rubbing on the frame at full steering lock. Personally, I would go with the 305/65-17's (33x12.50).

im goin to go with the 305's and how much life can i get out of some bf all terrains..keepin them rotated and balanced...?

I have 55,000 on mine and am beginning to wonder if they are ever gonna wear out! I plan on replacing mine at 60,000 miles, mainly be cause I want 35's, but I have no doubt I could easily get over 70,000 miles out of them.

You will have some rubbing

im running 295/70 terra grapplers right now...how much bigger are the 305/65 bf all terrains..?

A 295/70-17 is basically a 34x12.00-17 tire. A 305/65-17 is basically a 33x12.50-17. So the 305/65-17 would be about and inch shorter and 1/2 inch wider than a 295/70-17. However, I don't think the BFG AT KO is available in 305/65-17. They do make a 315/70-17 (35x12.50-17) and a 305/65-189 (34x12.50-18)

LT305/65R17/E is a new size that bfg came out with...

Sweet! It was needed.