Speed wobble (1)

Hi everybody, I have an experienced rider coming to see me soon who has suffered speedy wobble on three difference makes of bikes & sizes, downhill & flat roads and windy and non windy conditions. He is apparently very low at the front and likes to be over the bottom bracket(road bike) with an inline seatpost. I would be very interested on people’s thoughts on this particular problem and especially slowmans views please.

Sounds like he’s not balanced over the bike. Too much weight on the front can aid in speed wobble. Or he’s death-gripping the bars.