Once again, its the speed at load rating that I keep harping on.
These are the tires I have on the wheels that came on my Montana: Firestone Transforce HT LT235/85R16 106mph at 3042 lb..I'll take this over an ST 65mph trailer tire.
LT tires have greater strength for sustained speed at load.
http://www.tirerack.com/tires/BigPic...=yes&tab=Specs