If they are tied down properly they don't move at all. I try to get the straps to go over the tops of the tires to get more force directly on the tires. You couldn't do two sleds on it though. they are to long the side load and to wide to rear load double, so the sled deck is a better option in your case.How is that for hauling,.. does your atv slide around up there? I looked awhile back at those but they were fairly expensive and I needed to haul 2 sleds or 2 quads. My hauling truck is a 3/4 longbox diesel with a sled deck and the Ford is to just bomb around in.I love my Diamondback Toneau cover. Touring fits on my long bed rear loaded or side loaded. And I still have a full bed worth of secure waterproof storage. But then again, I'm not driving a ford either.
and no, it wasn't cheap. but it was bought for the purpose of being able to take two machines and my travel trailer places. So in the long run, it's well worth it to me.