anyont got extreme rims?an need tire size 4 later

lookin for some clean stock rims for my 91s10 like from an extreme, jus so i will be able to drag my truck till i get rims. But also i will be getting 20's sooer or later an i was wonding whats the smallest tire size i could get. Jus for the estimate so i could know how much to take out my fire wall