The last time I went to the tire store the guy did not want to sell me my 285/75x16's for installation on stock 7" Chevy aluminum wheels. He said their chart did not recommend it. Well he just removed a set of the same tires that went 60,000 miles and I had a set of all terrains on it previously, same size. So after having 2 sets of 285's on the Suburban that went over 110,000 miles all of a sudden he won't do it because of his chart.
First he tried to tell me the wheels were only 6.5 wide, next he said they would wear badly and lastly he referred to his chart.
Chevy GMT 400/800 aluminum wheels are 7" wide, 2 sets of tires with over 50,000 miles a piece put his wear argument to bed and his chart was challenged by my argument that he will install a 12.50 wide tire on an 8" rim, but not put a 11.25 wide tire on a 7" rim?
By the time I was done arguing with him in the crowded sales room of the tire store, even the customers waiting were looking at him like he was an idiot. I finished up with the comment that 3 other tire stores will sell me what I want if you don't, so make up your mind or I'm leaving. I got my tires.
A good tire store will actually mount up a tire on your rim and cycle it to test clearances. The "chart" is posted online and is just a liability thing for the tire companies to avoid uneven wear claims or tire rubbing on certain vehicles. It is very generic though. The tire store employees are usually believed by customers and it's an easy way for most tire stores to sell aftermarket wheels to fit their chart. Usually the aftermarket wheels have different off sets than stock wheels and in many cases rub or have more clearance issues than stock rims. Remember also Z71's run 265 tires from the factory, there is no logical reason you can not go one size bigger on a stock wheel.