If you have a rim designed for 10 " tires and put 12 " wide tires on it ,won't this balloon them up to stand taller then the front and put stress on your driveline when in four wheel drive.The same thing would be true if you used 7 inch wide after market rims on front and back and used two different tire widths ,that extra width has to go somewhere if it can't go out when inflated it will go up, or wouldn't it be enough to worry about, just a thought