For my 2000 Excursion, I ran 10-ply Michelin tires towing a 35' TT weighing about 9,500 lbs. loaded for camping. So far with my 2009 F450, I have only had to by one new set since I bought it in 2014 and I bought the same Continental tires that came on it from Ford.
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ETCrockett
2016 Jayco Pinnacle 38FLSA
2009 Ford F450 DRW
RVing all my life......1st Jayco