Please confirm you have a class III two inch hitch with a capacity of 500 lbs at a minimum (bumper hitches, extension hitches, and hitches with cantilevered sections allow too much hitch movement and are inadequate). One item to check is if a ladder could possibly interfere with the rack. Trailers and RVs produce extreme forces on racks and bikes. Take extra care to strap tight and use rubber bands (or bike tubes cut in ~1 inch sections) placed on the brake levers to decrease natural motion between bike and rack.