I want to go to a bigger tire on the rear of my 97 astro 2 wh. Anybody know what the limit on a bigger tire on the rear axle for fitment and clearance is :-k ??/ And what size rim and what the back spacing should be

??/ Some body said that the astro's came factory with a wider wheel ( Wider that 6 1/2" )

in some years as I would rather go with the stock looking rim if possible ??/