Wobbly handle bars

[_lou_]

Hello fellow riders,

I have a fixed gear that I built from parts (nice Reynolds 531 frame I could not leave
alone in the classifieds), with a carbon fork.

Something really weird happens from time to time, and last time it almost threw me over
my bars : the handle bars start to oscillate (left to right) at around 20mph, to a degree
that I have to very firmly hold them to avoid things going out of control and crash. I
have no idea what is causing this, but it is really scary.

Has anyone ever experienced this ? Is there a cure for it ? I'm guessing it has something
to do with the geometry of the bike, but really don't get it.

Lou

[border-rider]

So just what causes shimmy ?

Worth a read.

[_lou_]

Thanks for the link, a lot of the comments make sense (not so much the coconut bra, though....).