What are the physics behind high-speed bike wobble, shimmy, or whatever you want to call it?
We were descending today at ~60 mph and my friends bike started to shimmy uncontrollably when he pulled around my draft. Luckily he regained control and didn't eat pavement.
I've had the same thing at lower speeds when I'm not firmly planted on the seat. We had some debate on what causes the problem. His bike is in great shape with no loose parts and good wheels and tires. My friend believes the shimmy was due to the wind turbulence behind me. Any answers?