I have the full storage cover for the 500 and it does stay on well. But, a week ago we had two days of 40+ mph winds with a few 65 mph gusts and it did come off. I was lucky and it caught in my hedges. I put it back on with two 12ft. lashing straps hooked together and gave it a coat of camp dry water proofer. I don't think it'll come off now.