High Speed Shimmy

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?

Litespeed.
--
JT
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Remove "remove" to reply
Visit http://www.jt10000.com
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Matt Grath said:

I know this is a well worn topic, but, I've experienced shimmy with
my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
riding the same hills for 15 years with no problems (for the past 8
years on Cannondale, which, sadly developed a cracked frame). The
shop tightened the spokes, which helped but did not solve the
problem. Anyway, the point of the post is to poll folks - is this a
Lightspeed issue?

You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars. I am a bit suspicious when
you say spoke tightening had an effect. Unless the spokes were
rattlingly loose, spoke tension does not affect wheel stiffness.
That is, spoke preload does not affect elasticity.

You might save some time if you haven't seen the FAQ item by looking
it over:

http://www.sheldonbrown.com/brandt/shimmy.html

Jobst Brandt

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt

Is this a large frame? It could then be a "Lightspeed issue" due to the
flexier tubes (flexier than your prior Cannondale). But there are so many
other variables, as pointed out in the FAQ that you've no doubt read. The
FAQ really is the definitive work on the subject.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt

as said by the other posters, if it's a large frame, it could be a
lightspeed issue. /but/ tell us more about your wheels first. wheels
with better lateral stiffness do help mitigate this problem to a large
degree - try a different rear wheel with thicker [stiffer] drive side
spokes or stiffer rim. it affects the resonance, hopefully tuning the
wheels out of their harmonic with the frame.

Quoted message said:

Matt Grath said:

I know this is a well worn topic, but, I've experienced shimmy with
my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
riding the same hills for 15 years with no problems (for the past 8
years on Cannondale, which, sadly developed a cracked frame). The
shop tightened the spokes, which helped but did not solve the
problem. Anyway, the point of the post is to poll folks - is this a
Lightspeed issue?

You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars.

Troll-o-meter says: 3.2

In what universe to you live in? One in which riding no-hands at 35-40mph
is common enough that you'd think it's valid that this point should be
clarified?

Troll Report said:

Quoted message said:

Matt Grath writes:

Quoted message said:

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with
my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
riding the same hills for 15 years with no problems (for the past 8
years on Cannondale, which, sadly developed a cracked frame). The
shop tightened the spokes, which helped but did not solve the
problem. Anyway, the point of the post is to poll folks - is this a
Lightspeed issue?

Quoted message said:

You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars.

Troll-o-meter says: 3.2

In what universe to you live in? One in which riding no-hands at 35-40mph
is common enough that you'd think it's valid that this point should be
clarified?

No one ever says maybe its a tire. I had two tires do the same.One
dating back to 11 years ago. And one just last month. Had the wheel
trued and it went away but came right back. So I said try another
tire. Fix.

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt

What wheels??
Could be lots of things and after correcting these it may still
shake.
HS, bike fit, fork/frame alignment, wheel dish, cable housing
length.....

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt

Speaking of Litespeed...had a persistent rumor that American Cycle
Group has gone belly up-anybody else heard this??

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Matt Grath said:

I know this is a well worn topic, but, I've experienced shimmy with
my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
riding the same hills for 15 years with no problems (for the past 8
years on Cannondale, which, sadly developed a cracked frame). The
shop tightened the spokes, which helped but did not solve the
problem. Anyway, the point of the post is to poll folks - is this a
Lightspeed issue?

You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars. I am a bit suspicious when
you say spoke tightening had an effect. Unless the spokes were
rattlingly loose, spoke tension does not affect wheel stiffness.
That is, spoke preload does not affect elasticity.

You might save some time if you haven't seen the FAQ item by looking
it over:

http://www.sheldonbrown.com/brandt/shimmy.html

Jobst Brandt

I was experimenting with this shimmy descending Sand Hill rd.towards Old
LaHonda. I can generate a shimmy when I induce it with my muscular movement
without pedaling. No shimmy when I ride with no hands
and not pedaling. I also found out I can take out the shimmy by "pedaling"
on the decent after inducing it with muscular movement.
-tom

someone said:

Quoted message said:

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy
with my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have
been riding the same hills for 15 years with no problems (for the
past 8 years on Cannondale, which, sadly developed a cracked
frame). The shop tightened the spokes, which helped but did not
solve the problem. Anyway, the point of the post is to poll folks
- is this a Lightspeed issue?

Quoted message said:

Quoted message said:

You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars.

Quoted message said:

Troll-o-meter says: 3.2

Quoted message said:

In what universe to you live in? One in which riding no-hands at
35-40mph is common enough that you'd think it's valid that this
point should be clarified?

I guess you don't ride bike or you would know that max speeds on fast
descents are achieved with hands on the bar stem in a tight crouch.
Even in that position the soft mass of the hands on the stem suppress
shimmy for most bicycles.

Just the same coasting at 40mph riding no-hands in common among the
people with whom I ride. Typically coasting down CAL HWY84 to La
Honda is a 40mph descent that rolls well sitting up with hands behind
ones back.

I've noticed that riders sneer incredibly when I ask whether their
bicycle rides straight when ridden no-hands, because I note that the
wheels are skewed to one another. The response often is "I don't ride
no-hands!" in a tone as if I had asked whether they ride without a
helmet.

Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

Jobst Brandt

Quoted message said:

I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt

It's a complicated interaction between the bike geometry, stiffness,
natural resonant frequency and your own body and riding position. It
occasionally happens with certain riders and certain bikes. I
experienced shimmy/speed wobble when I was a teenager, but never on any
bike since (and except the fixie, they've all been up to 55mph or more).
Things to try would be checking your position, different tires and
moving any luggage (bar bags have a bad reputation for contributing to
shimmy). Last resort - try a different fork. You may be able to borrow
one from someone, all A-head forks being pretty swappable.

Quoted message said:

I guess you don't ride bike or you would know that max speeds on fast
descents are achieved with hands on the bar stem in a tight crouch.
Even in that position the soft mass of the hands on the stem suppress
shimmy for most bicycles.

I had a shimmy problem once but it was on a motorcycle and not a
bicycle. Riding my Kawasaki 750cc suicide bike up highway 17 to Santa
Cruz at 90 MPH it had a nasty shimmy in the turns at that speed, mostly
left turns. I took it back to the dealer and it turned out to be a bad
run of tires, Pirelli I think, and replacing them with Dunlops cured the
problem. The tire issue may or may not apply to bicycles, but that is
the only time I have had a shimmy problem on the road.

Quoted message said:

Just the same coasting at 40mph riding no-hands in common among the
people with whom I ride. Typically coasting down CAL HWY84 to La
Honda is a 40mph descent that rolls well sitting up with hands behind
ones back.

That reminds me of highway 9 coasting down from summit road back to
Saratoga where 40 MPH was on the slower sections and could be done
sitting up and no hands. Getting into a crouch I used to pass cars going
down at who knows what speed, but the drivers sure did a double take.
This was in 1963 on an even older Peugeot ten speed.

Quoted message said:

I've noticed that riders sneer incredibly when I ask whether their
bicycle rides straight when ridden no-hands, because I note that the
wheels are skewed to one another. The response often is "I don't ride
no-hands!" in a tone as if I had asked whether they ride without a
helmet.

Where have all the young folks of bicycling gone?

America, Home of the brave, land of the free sissies?

Quoted message said:

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

Jobst Brandt

Bill Baka

Side note. I saw a news article that said car fatalities are climbing
again because the drivers seem to think that the air bag and other
features will protect them no matter how stupidly they drive.
I don't think air bags count when you hit a semi or train.

Quoted message said:

I was experimenting with this shimmy descending Sand Hill rd.towards Old
LaHonda. I can generate a shimmy when I induce it with my muscular
movement without pedaling. No shimmy when I ride with no hands
and not pedaling. I also found out I can take out the shimmy by "pedaling"
on the decent after inducing it with muscular movement.
-tom

As you have so capably demonstrated, shimmy is a function of the bike *and*
rider. It's a dynamic system, susceptible to far more variations from the
rider than from road conditions or even a component issue.

This comes up so often at my end of the business. We had one person who was
terrified there was something very wrong with her bike because she could get
it to shimmy/wobble at 38 mph descending this one particular road when there
was a crosswind on a cold day. *All* those things had to exist for the
shimmy to occur. And yet it was the bike at fault.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Jobst Brandt said:

...
Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

How can you stand to ride in such ugly terrain?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Johnny Sunset said:

Jobst Brandt said:

...
Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

How can you stand to ride in such ugly terrain?

Ugly? It's beautiful compared to where I now ride. I've been to a lot of
those places and miss them. The Big Basin--Mount Umunhum, and Highway 1
rides were some of the best. Once on Highway 1 I was looking down at the
ocean and saw a small Piper flying below me, about 50 feet over the
waves. A Kodak moment and no camera. I miss all the tall trees and being
able to be freezing when it was in the 80's in San Jose. Inland, where I
ride it is just hot and hotter. I never found that cave though.
Dang.
Bill Baka

Quoted message said:

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Tom Sherman said:

Quoted message said:

...
Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

Quoted message said:

How can you stand to ride in such ugly terrain?

Hold a stiff upper lip and suffer! Even while riding no-hands.

Jobst Brandt

Mike Jacoubowsky said:

Quoted message said:

I was experimenting with this shimmy descending Sand Hill rd.towards Old
LaHonda. I can generate a shimmy when I induce it with my muscular
movement without pedaling. No shimmy when I ride with no hands
and not pedaling. I also found out I can take out the shimmy by "pedaling"
on the decent after inducing it with muscular movement.
-tom

As you have so capably demonstrated, shimmy is a function of the bike *and*
rider. It's a dynamic system, susceptible to far more variations from the
rider than from road conditions or even a component issue.

This comes up so often at my end of the business. We had one person who was
terrified there was something very wrong with her bike because she could get
it to shimmy/wobble at 38 mph descending this one particular road when there
was a crosswind on a cold day. *All* those things had to exist for the
shimmy to occur. And yet it was the bike at fault.

it is. bike shouldn't do it under any circumstances. the resonance of
the frame and wheels should be different, not coincident.

Jobst Brandt said:

Tom Sherman said:

Quoted message said:

...
Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

Quoted message said:

How can you stand to ride in such ugly terrain?

Hold a stiff upper lip and suffer! Even while riding no-hands.

Can't compete with this for scenery: <http://tinyurl.com/2dmnjr> and
<http://tinyurl.com/2gprme>!!!

On 20 Jun 2007 14:53:29 GMT, [email hidden] wrote:

[snip]

Quoted message said:

Where have all the young folks of bicycling gone?

http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html

Jobst Brandt

Dear Jobst,

I chanced upon this picture while looking for bicycle pictures in the
Denver Museum online archive of western photos and thought of your
post for some reason.

I assume that's you, second from the right in the cap and knickers,
listening to the other five fellows at Stanford asking where have all
the young folks of bicycling gone:

http://photoswest.org:8080/cgi-bin/cw_cgi?fullRecord+16444+594+26219+1+0

The full size view shows your bike on the extreme left:

http://photoswest.org/cgi-bin/imager?00130291+C-291

Cheers,

Carl Fogel