Now you do know that by installing LT tires in place of ST tires on an RV you may create reverse gravitational chaos with in the universe....correct?
I installed 235/85-16 in place of the 235/80-16 on my Wildcat which had about the same clearance and am doing fine. Nice thing is that I don't worry about staying at or under 62mph or the strength of the tire running down the road.
There is also another size that goes down in diameter but I can't think of the size, it's a 245/75-16 or something along that tract. It will be a smaller diameter but a hair wider and usually has a little greater weight limit.
Either way, good luck,
2013 Ford F350 FX4 4x4 PSD
2013 Wildcat 353LS
2015 Day/Nights Camped 5
2014 Day/Nights Camped 29