[Vwdiesel] Tire and Rims on VW pick-up

[Caleb Van Dyke]

I am running a 14", 165/R14 tire (mounted on Audi Rims) on my diesel VW pick-up right not. I am thinking about using my older 13" steelies while I re-do the 14" rims. The stock tire evidently was a 160/80/13 or a 170/75/13. I am thinking about going with the 170 series tire, but was wondering if I should even upsize maybe to a 185/70 or 75 13 incher. Will going with the 170 or 185 13's give me any better fuel economy seeing that's whay VW recommends? 

Any help would be appreciated.
 

Caleb Van Dyke