Another wheel backspacing question

Goin from a 255 to a 275 will increase the dia. to 28" which may rub the front portion of the wheelwell. You may want to consider moving the rear back a bit if you decide on a taller tire. You can shim the front hangar but you may have to lengthen the driveshaft as well, pending insertion into the yoke. You also have to consider what happens when you drive, cornering, turning, etc,,,. Checking them statically insn't foolproof. I'd go w/the combo w/the most spring/wheel lip clearance.