Got an 82 Pickup and I want to toss some rubber on it to replace the **** that's currently there.
It's stock ride height far as I know. Can I toss some 33x12.50 tires on it?
Will I need to change the rims?

I'd like to run 37x12.50s once I do the suspension over, should I widen the axles or use spacers or what?

FYI, the rear has a flat bed.

 

Likely 31x10.50 without a lift. You can fit 33s with a few inches of lift (suspension or body). Stock rims are likely 6" wide, a 33x10.50 works well on those:
http://www.4crawler.com/4x4/BFG_AT_KO.shtml

Probably need an 8" rim for 12.50s.

 

I know I'll need a wider rim.
What I'm wondering about is backspacing on the rim to make it all work with my truck.

 

Max is around 3-3/4", stock is 3-3/8", less is wider and better for stability, but may require more lift to fit a given tire.

 

So if I go to 3-3.5" BS, I'll need to wait till I lift it then.

Thanks for the info!