Ok so I've been hunting on the internet all night trying to find the backspacing and offset and blah blah blah for my wheels cuz I'm thinking about buying new ones.. I cant just go measure cuz my wheels have tires on them and I cant yank one off.. So if somebody could please tell me the specifications so I know what the heck I need I would really appreciate it..

The truck is a 91 3/4 ton Dodge