My bad, I think I put too many suggestions up before. Ok let me say it this way.

When I had my stock 235-55-16, which are 26.2", they only rubbed when turned fully or when going thru a dip and the suspension compressed. Then they also hit the top of the inner fenders. So now with my 18s, 245-40-18, they only seem to rub slightly on the frame when turned fully, but don't rub the fender at all when going thru big dips. Now that is a 245 wide tire, but a 40 series. The sidewalls are very stright. My 235-55-16 tires have a very bowed, or curved sidewall, maybe this sticks out further than the 18s. Not sure. But if you want to drop your truck and go with a wider tire, you could get a 255-50-16 which is 26" tall, or 245-50-16 which is 25.6" tall. Something at or below 26.2" I guess. I just make sure I don't crank the wheel all the way.

Maybe you could go to your local tire shop and see what they recommend. I'm sure they know a lot more about this than I do.
So hopefully this helps more. Let me know if you have anymore ?'s and I'll try and help out. -Scott