Help! I have an 04 GMC Sierra EXT cab with 265x75x16 and I'm looking to put bigger tires on but I'm not looking to lift the truck.  Anyone know how big I can go? I have a tire shop telling me I can squeeze 315x75x16's but looking at my clearance up front I can't see how they won't rub.  Anyone have an idea?  

i have a friend who has 31 x 10.5 x 15 on that body style 1/2 ton. there tight but don't rub too bad.  

265/75 is about the same as a 31/10.5... just fyi..

Yea, that shop is full of it. 315/75 is about a 35/12.5, to big for stock for sure.

I would guess that the biggest you could fit would be about a 33/10.5, or a 285/75 with no to minimal rubbing.  

Getlemen,  thanks for getting back to me on my situation, I'd hate to buy too big and then have issues.  I was sold on the 315's but I think I will settle for 285's.  Thanks again