I have read through quite a few pages on this thread and still can’t find a definitive answer. Will 275/70/17 rub really bad on a stock setup?
It's hard to say as with the loose tolerances of plastic body pieces, every truck is a little bit different.
Chances are that it would not rub "really bad" but they would perhaps rub a bit in the normal spots: mud flap and fender liner. Both are super simple to adjust enough to prevent rubbing.