Ive been looking at some wheels to run a 315/70/17 tire on. Will having an extra inch help out much as far as the life of the tire goes. Also I would like to keep psi up in the tires for the best mpg possible. Any thoughts. Thanks Joel

 

the 9's would wear a little better. Most 315's are recomended to run on at least a 8.5" wide wheel, but either would work.

 

Backspacing is of more importance....

 

Like stated above, 9" wide will fit the tire better, but an 8" is fine. Just keep them rotated.