for my winter setup i went with 17" wheels with 234/45-17 tires all the way around, and for summer i had 19" front 20" rear with 235/35-19 tires front and 285/30-20 tires rear with no spacers. so i would assume that you could probably go with a 295 or maybe even a 305 in the rear if the wheels had the proper offset, or spacers where used.