If your willing to spend the additional money, I suggest going to 17.5" rims and commercial tires(tires are actually cheaper than the high-end 16's). Many of the newer and heavier RV's have gone this route, rather than a third axle! The tires and rims offer a higher load rating that can be had with a 16" while offering the same OD. The only issue that I have is that they require 120 - 125 psi for full inflation. memtb
