A few weeks ago, I experienced, for the first time, that I am getting
front wheel wobbling on descents. It was on a steep hill that I have
been down time after time, but this day I was scared half to death
that I was going to lose control of the bike and eat the pavement.
I look my bicycle over, but I can't see any mechanical problems that
might cause that to happen. I seem to be tensing up on descents when
I didn't used to have that problem. Since those few weeks ago, I am
still experiencing the same effect and it is very scary. The people
behind me immediately try to pass me for fear they may end up going
down if I go down.
It's become very annoying. It feels more psychological than anything
else.
I have lost a bit of weight lately from all the riding I have been
doing, so I am flying up hills with relative ease where I used to get
dropped before, but now I am losing a grip on descents when I used to
fly down hills ahead of everyone else, even when I wasn't aero,
because my weight giving me advantage. However, now that I am losing
the weight, I seem to be shimmying like crazy.
It's become like a roller coaster feeling.

Have you read the FAQ on bicycle shimmy, found here-
http://draco.acs.uci.edu/rbfaq/FAQ/8h.5.html? It covers the subject very
well.

But reading your post, it really appears that you've already figured out
what's caused it- your loss of weight. You've changed how you interact with
your bike. Remember that a bike isn't stable without the help of someone on
it, and, well, you changed. That's not to say there might be something going
on with the bike, but we do know, for a fact, that the most-significant
variable, you, are different now than when the bike didn't shimmy.

The question is, what can you do about it? That's a really tough one,
because once you've lost confidence in a bike, you approach it in a way that
makes it more likely to shimmy (by being, as you said, tense). You might
need to make some sort of major change in your position, for no good reason
other than to force you to do things differently than before, and make it
feel as though something has really changed. I've seen cases where it just
doesn't matter; once someone's lost faith that their bike will be stable,
there's nothing you can do to change it. It becomes a self-fulfilling
prophecy.

But first, if you haven't read the FAQ, do so. It often helps to read an
authoritative, unattached (to your situation) view of the problem, and
potential solutions.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Michie" wrote in message
oups.com...

A few weeks ago, I experienced, for the first time, that I am getting
front wheel wobbling on descents. It was on a steep hill that I have
been down time after time, but this day I was scared half to death
that I was going to lose control of the bike and eat the pavement.
I look my bicycle over, but I can't see any mechanical problems that
might cause that to happen. I seem to be tensing up on descents when
I didn't used to have that problem. Since those few weeks ago, I am
still experiencing the same effect and it is very scary. The people
behind me immediately try to pass me for fear they may end up going
down if I go down.
It's become very annoying. It feels more psychological than anything
else.
I have lost a bit of weight lately from all the riding I have been
doing, so I am flying up hills with relative ease where I used to get
dropped before, but now I am losing a grip on descents when I used to
fly down hills ahead of everyone else, even when I wasn't aero,
because my weight giving me advantage. However, now that I am losing
the weight, I seem to be shimmying like crazy.
It's become like a roller coaster feeling.
One rider, who is a fellow team mate, and is a cat 3 racer, told me to
try pulling my knees in using my them to pull up under the top tube
and sit back farther on the seat and get more aero, but I still feel
like I am shimmying, and he noticed that I was to, even going down a
hill at a mere 25 mph.
Finally, I tried turning the biggest gear on the bike while going down
hill, or at least spin the pedals even if it wasn't giving me
momentum, and it seemed to help. I felt more stable, like my center
of gravity was under better control.

Does anyone have any advice to help me conquer this newly chronic
problem?