First if you're talking of hauling a horse trailer think of your cargo. You want that truck to handle as smoothly as possible in both shifting and side to side motion. Also the idea of a blowout, even if maintaining control you might get a little swerving going on. You want a solid stable platform for towing horses. I know what the ratings say, but if you got a heavy trailer then you want the dually. Here in horse country, 90% of these cowboys haulin large horse trailers all have duallys. Get the dually and don't look back....