30's will fit and about the biggest you can go without rubbing. My buddy has 31s on a stock 91 and his rubs.

 

x3 on 30"

Stock rims are 15x7, I can't see how 32's would fit! That's awesome. 30's fit easily on stock rims, too.

But yeah, 30's fit fine with stock suspension as long as you're not flexing. Perfect for mall crawlers or for keeping it to logging roads! that's what I did for 2 years before putting my lift on.