Tire size

I have 225 70 15's on the back with a 4.5 inch backspace and they just clear the springs and have about an inch between the tires and fender.
This a factory 7.25 rear end.

A 235 would probably fit ok if a 3.5 backspace was used.
Can't swear to it.

Also I run 205 70-15 on the front with a 4.5 backspace and they are fine.