A couple of years ago I got a horrific speed wobble on a westerly descent to the west of Schull Co.Cork, during a triathlon relay. It was so bad I almost crashed and having stopped the bike I was convinced until I saw otherwise, that the frame was fractured. In 30 years of cycling I'd never experienced its equal.
Last Saturday I took part in the same triathlon relay and again the wobble started (this is the only hill on which this bike has wobbled. It's very fast and irregularly surfaced). I know the tricks to correct the wobble. I shifted forward, reduced but not gone, gripped top tube with knees, not gone. Sat on nose of saddle, nearly gone but not gone. But then, shifted hands to forward area of drops, nearly gone, hands on hoods, completely gone. During the sequence I repeated all these positions. Hands on drops straight down, immediate wobble and even gripping very loosely the same thing. Gripping rounded surfaces of drops, much less, hoods, totally gone.
I've never seen this documented like this but others may have experienced the same but not communicated.
It may be that the grip on the hoods is naturally very loose..
Has anyone an explanantion?