Tires too big for Demon?

255/60-15s on my Duster, no problem. Stock backspace, stock axle width. Trimming the inside of the fender lip would allow a bit more, but the springs are starting to get close too, so I think realistically that's the most you're going to get before running into clearance issues with the stock chassis dimensions:

http://stuff.is-a-geek.net/PhotoAlbum/Cars/Pics/duster_08.jpg