I have 2004 Dually 2WD and after getting 55K on the original GY's I went to Toyo Open Country A/T and had them siped as well. So far I have about 12k on them and they look good, handle well, ride nicely. I carry a 11' Lance, truck feels better with these tires than the GY's... more stable feeling... I am testing at running at different pressures with camper... down to 65# all around and it seems fine, started at 80 max pressure and working my way down... now i get a good empty and loaded driveability. I got them at Les Schawb here in the NW, also I cahnged my shocks... I suspect that had something to do with the sway and other characteristics... the OEm shocks were soft on the tube compared, I tested them at the dealer when they came off... big difference.
Don't forget the shocks... they do things!!!
The tires and shocks cost $1500 for six and switching to 19. 5 wheels and tires would have been about $4700... so i decided to live with the 17's
I am Pleased withthe Toyo's The siping works, wet road, light and no break free on rears at stop light anymore! NICE!!
BTW, I saw a new dually with a bigger tire on a 17" and the distance between tires looked like it would take a chain if Had to use them. Don't remember the size, mine are 235 80R/17
hope this helps! PJ