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From: scroggs@uiucdcsp.UUCP
Newsgroups: net.bicycle
Subject: Speed Wobble Troubles
Message-ID: <4200001@uiucdcsp.UUCP>
Date: Mon, 19-Nov-84 11:41:00 EST
Article-I.D.: uiucdcsp.4200001
Posted: Mon Nov 19 11:41:00 1984
Date-Received: Wed, 21-Nov-84 01:00:39 EST
Lines: 20
Nf-ID: #N:uiucdcsp:4200001:000:1184
Nf-From: uiucdcsp!scroggs    Nov 19 10:41:00 1984

Speed Wobble Troubles
Last spring, I purchased a custom frame through a reputable dealer from
a good company (King of Mercia built by Mercian of England).  I took the
creation to the mountains of New Mexico, where I discovered that the bicycle
becomes unstable at speeds of about 28 miles per hour (a friend clocked me
while going down a hill).  At 28 and above, the handlebars begin to oscillate,
and at about 32 mph I almost lost control of the bicycle.  The frame has
'sport touring' dimensions.  I noticed that placing weight in
my front panniers mounted on the low rider rack supresses the wobble,
allowing me to feel safe at speeds around 25-30 mph.  I do
not consider myself a fast rider, but I do like to coast down moderate
hills without having to use the brakes for fear of losing control.
     The dealer has assured me that the frame has no faults (like the
fork being out of alignment), and I have been unable to see any
problems with the machine.  
     Does anybody know the cause of these 'speed wobbles'?  Does
anybody know of studies (scientific) which have tried to locate what
makes frames stable/unstable?  Could a change of componets bring about
more stability?