Any of you ever notice speed wobble "windows"? At a certain speed the wobbles come on, but then they pass as you go faster. Like when a plane breaks the sound barrier, they kinda lose control while they're going through the sound barrier, but then get complete control back once they break through it. Not like it would be at all the same physics at work, but you see the analogy.
I wonder if there's some whacky physics going on with the king pin at certain speeds under certain conditions.