I have these mounted on the top of my ARE truck cap with the factory installed tracks and Yakima towers/straight bars. I ran 2600 miles at an average of 72 mph with a 14' Malibu stealth and a 9' zydeco strapped on. They were secure and neither hull was deformed. A bit of a trick to get both boats up that high, but I understand there are accessories to help with that. Great racks and RA is awesome to deal with. I'm very happy with them both.
2012 Ram 2500