Originally Posted by btblueskies
This video may help you wrap your mind around it. There is another one I cannot seem to find that helped me 'get' it. The key is that the rotating structure is on a movable axis. If it is on a fixed axis it will not work. Since the tires are attached to suspension, it works in this case. The key is that when the tire starts to spin fast enough to vibrate, the beads move around randomly, and they happen to land in spots that reduce the vibration. The beads in essence 'migrate' to the locations that stop the vibrations. Then they stop moving.
I am in on a bucket o' beads as well. This is the video I saw a couple of years ago that allowed me to believe in this magic:
Not dyna-beads, but a similar model of a product for large trucks. They freeze frame some shots to show you where the beads move to. This idea seems like a great idea for all vehicles. That is until a bunch of beads end up on a road surface and mingle with traffic.