Not a dually, but it doesn't make much difference for tires.
I run Nitto Duragrapplers on my 08 2500 (of the 285 75/17 variety). Great tire. Had a set on my 03 2500 as well before I traded it in. They wear well, ride nice, and best of all are quiet.
[B]03 Rubicon[/B] (Weekend Toy) [URL="http://www.jeepforum.com/forum/f176/marshals-03-rubi-2822258/"]Build thread[/URL]
[B]11 Ram 2500 [/B] - H&S tuned 6.7 Cummins (DD/Tow Rig)
[B]05 Liberty Limited[/B] (Wife's): Minor mods, OME/JBA Suspension, 245 70/17 Duratracs