rwiles, there is a great recap by OTRA15 in the 20-footers thread, post #1249.
Most in this thread have opted for the Michelin Defenders
http://www.tirerack.com/tires/tires....DTLX&tab=Sizes
I've seen other thread when they have opted for the Michelin Ribs.
http://www.tirerack.com/tires/tires....omCompare1=yes
Personally I'm tracking the Nokains so I can stay with the 15" OEM rims but still get about the same load rating (LT235/75 R 15 116/113 S) as the 16" Defenders (LT225/75 R 16 115/112 R) . Now that Walmart carries them, the availability appears to be improving.
Bob