Death wobbles on Giant TCR?

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

Quoted message said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms.
I can control them by gripping the top tube between my knees and
unweighting my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

Gsk, I and a good friend both have Giant TCRs (both carbon and aluminum) but
have none of the wobble you describe. Any bike will wobble if it has loose
components. For this reason you might consider that there is some part of
the system that is not working as designed and more importantly could be
prone to failure as a result. I would think you might want take care in
checking the following for proper installation, adjustment, stress fractures
or manufacturing defects:
* Headset
*Fork
*Spokes
*Tires
*Rims
*Hubs
*Quick Releases
*Frame

I would hate to have you suffer a failure during a high speed decent!

Take care.

Dave

gsk said:

It seems I get the death wobbles on most high speed descents on my

Giant

Quoted message said:

TCR. The fork starts to shake shakes like crazy at anything above 60

kms. I

Quoted message said:

can control them by gripping the top tube between my knees and

unweighting

Quoted message said:

my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is

it

Quoted message said:

happening in the first place.? Any recommendations for a road bike

that is

Quoted message said:

death wobble free?

http://draco.acs.uci.edu/rbfaq/FAQ/8h.5.html

Dave Reckoning said:

Quoted message said:

It seems I get the death wobbles on most high speed descents on my
Giant TCR. The fork starts to shake shakes like crazy at anything
above 60 kms. I can control them by gripping the top tube between
my knees and unweighting my saddle but it's still scarey and a
nuisance.

Quoted message said:

Quoted message said:

Any solutions for this with the TCR other than what I'm doing. Why
is it happening in the first place.? Any recommendations for a road
bike that is death wobble free?

Quoted message said:

Gsk, I and a good friend both have Giant TCRs (both carbon and
aluminum) but have none of the wobble you describe. Any bike will
wobble if it has loose components. For this reason you might
consider that there is some part of the system that is not working
as designed and more importantly could be prone to failure as a
result. I would think you might want take care in checking the
following for proper installation, adjustment, stress fractures or
manufacturing defects:

Quoted message said:

* Headset
*Fork
*Spokes
*Tires
*Rims
*Hubs
*Quick Releases
*Frame

Quoted message said:

I would hate to have you suffer a failure during a high speed decent!

I doubt that these adjustments will have any effect on shimmy. I've
done many tests on this matter and propose the following:

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

Jobst Brandt
[email hidden]

Bonehenge <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

gsk said:

Any solutions for this with the TCR other than what I'm doing. Why
is it happening in the first place.? Any recommendations for a
road bike that is death wobble free?

How's your fit?

Barry

He probably has one each time it happens.

gsk said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms. I
can control them by gripping the top tube between my knees and unweighting
my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

The German magazine "Tour" found the Giant TCR to be on the flexible
side. Their high-end frame tests include lab measurements of, among
other things, head tube stiffness and fork lateral stiffness. They
mention that flexible frames can sometimes be more susceptible to
handlebar flutter, which sounds like what you are describing.

One solution might be to buy a stiffer bike.

I know of two people with the same complaint on medium size carbon fibre
giants.
When they approached the bike shop from where they were bought they were
told bad luck.
The guys refuse to ride down any sort of a steep hill now

Peter

Quoted message said:

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

Quoted message said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms.
I can control them by gripping the top tube between my knees and
unweighting my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

Dave Reckoning said:

Gsk, I and a good friend both have Giant TCRs (both carbon and aluminum) but
have none of the wobble you describe. Any bike will wobble if it has loose
components. For this reason you might consider that there is some part of
the system that is not working as designed and more importantly could be
prone to failure as a result. I would think you might want take care in
checking the following for proper installation, adjustment, stress fractures
or manufacturing defects:
* Headset
*Fork
*Spokes
*Tires
*Rims
*Hubs
*Quick Releases
*Frame

I would hate to have you suffer a failure during a high speed decent!

OK, check away but it's likely 'shimmy' which is actually
enhanced by a stiff straight frame with perfect bearing
adjustments and true wheels.

http://draco.acs.uci.edu/rbfaq/FAQ/8h.5.html

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

gsk said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms. I
can control them by gripping the top tube between my knees and unweighting
my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

You don't say how old it is. There was this one year where all the rear
forks cracked (check behind chainwheel and around both bridges, and a
bit later there was a carbon fork recall because of steerer pull out.
Check!
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Quoted message said:

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

Welcome to the club. Let me save you alot of time and frustration. Get
a different bike. Everyone's body and skill is different, but it's easier
to change the bike. Get something like a Specialized Roubaix or Serrota,
where the wheel bases are longer, and head angles arn't so steep. Before
changing bikes, the only thing that seemed to change the dynamic of the bike
at all, was different wheels in my case. A change to open pros seemed to
make the problem manageble, but didn't eliminate it. Good luck, but like
some previous posts, usually all those small adjustments usually don't do
didly.

greg asks-<< It seems I get the death wobbles on most high speed descents on my
Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms. I
can control them by gripping the top tube between my knees and unweighting
my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free? >><BR><BR>

I answer-speed wobbles can be many things and checking/fixing these many things
can sometimes not fix the problem. Frame alignment, fork alignment, tire
pressures, spoke tensions, headset adjustment, aeroness and wind of the rims,
frame...

I have a Merckx and have never had a frame that shook...DeRosa, Ciocc,
Nobilette...but all steel.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

jazzy-<< Get something like a Specialized Roubaix or Serrota,
where the wheel bases are longer, and head angles arn't so steep. >><BR><BR>

Interesting choices...Neither of which necessarily have longer wheelbases and
slacker head tube angles than many other frames.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

gsk said:

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

FWIW, I descend on my TCR1 at well over 70km/h without any sign of
shimmy or other problems, and so do others I ride with who also have
various carbon TCRs.

I'm not suggesting that you're riding badly, but there must be something
about the particular bike and/or your body that's causing it.

--
bpo gallery at http://www4.tpgi.com.au/users/mvw1/bpo

Quoted message said:

Dave Reckoning said:

Quoted message said:

It seems I get the death wobbles on most high speed descents on my
Giant TCR. The fork starts to shake shakes like crazy at anything
above 60 kms. I can control them by gripping the top tube between
my knees and unweighting my saddle but it's still scarey and a
nuisance.

Quoted message said:

Quoted message said:

Any solutions for this with the TCR other than what I'm doing. Why
is it happening in the first place.? Any recommendations for a road
bike that is death wobble free?

Quoted message said:

Gsk, I and a good friend both have Giant TCRs (both carbon and
aluminum) but have none of the wobble you describe. Any bike will
wobble if it has loose components. For this reason you might
consider that there is some part of the system that is not working
as designed and more importantly could be prone to failure as a
result. I would think you might want take care in checking the
following for proper installation, adjustment, stress fractures or
manufacturing defects:

Quoted message said:

* Headset
*Fork
*Spokes
*Tires
*Rims
*Hubs
*Quick Releases
*Frame

Quoted message said:

I would hate to have you suffer a failure during a high speed decent!

I doubt that these adjustments will have any effect on shimmy. I've
done many tests on this matter and propose the following:

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

Jobst Brandt
[email hidden]

well, for starters,
1. that gyro stuff is /way/ off. ski "bikes" shimmy, and there ain't no
gyro effect there.
2. not riding in the cold is impractical.
3. so what's your proposed solution?

your "method" of dealing with it is a band aid, it doesn't prevent the
injury in the first place. the solution is frames with adequate
torsional stiffness, but you'd know this if you'd bothered experimenting
with different frames with different tube diameters.

gsk said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms. I
can control them by gripping the top tube between my knees and unweighting
my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that is
death wobble free?

what wheels do you have? what size is the frame?

i spent quite a bit of time & money looking into this with a frame i had
a few years ago. i improved it significantly by changing from a campy
to shimano rear hub for the slightly better dishing angle & by using
unbutted spokes on the drive side rear for greater lateral stiffness.
tire & tire pressure the same. all other variables the same.

this said, they only real way to be sure is to try a different frame. i
can run my "shimmy" wheel on a good frame no problem, but that shimmy
frame was never entirely stable, unlike others i've subsequently had.
and i'm talking custom steel with identical geometry here - only
differences in build being tube type/diameter. big tubes are the way to go.

shimmy is an equation with two main harmonic factors - frame & wheels.
if your frame has inadequate torsional stiffness in the first place,
you're going to have a hard time eliminating it.

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

Quoted message said:

Quoted message said:

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

Quoted message said:

It seems I get the death wobbles on most high speed descents on my Giant
TCR. The fork starts to shake shakes like crazy at anything above 60 kms.
I can control them by gripping the top tube between my knees and
unweighting my saddle but it's still scarey and a nuisance.

Any solutions for this with the TCR other than what I'm doing. Why is it
happening in the first place.? Any recommendations for a road bike that
is death wobble free?

Dave Reckoning said:

Gsk, I and a good friend both have Giant TCRs (both carbon and aluminum)
but have none of the wobble you describe. Any bike will wobble if it has
loose components. For this reason you might consider that there is some
part of the system that is not working as designed and more importantly
could be prone to failure as a result. I would think you might want take
care in checking the following for proper installation, adjustment,
stress fractures or manufacturing defects:
* Headset
*Fork
*Spokes
*Tires
*Rims
*Hubs
*Quick Releases
*Frame

I would hate to have you suffer a failure during a high speed decent!

OK, check away but it's likely 'shimmy' which is actually enhanced by a
stiff straight frame with perfect bearing adjustments and true wheels.

http://draco.acs.uci.edu/rbfaq/FAQ/8h.5.html

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

You and Jobst are probably correct, but I have had front end vibration that
was my own damn fault. The first time I worked on my threadless headset I
didn't know that the cap had to be snugged down before you tighten the stem
and at 30 mph voila -- shimmy.

--Art

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

Quoted message said:

I know of two people with the same complaint on medium size carbon fibre
giants.
When they approached the bike shop from where they were bought they were
told bad luck.
The guys refuse to ride down any sort of a steep hill now

Peter

Funny thread - I had an aluminum TCR that drove me nuts for that reason, and
tried a carbon one afterwards in the hopes that it might be better since I
liked the bikes otherwise. Nope, still wobbled like crazy on straight
descents. The carbon one had a noticeably flexy head/top tube and you could
set it off just by whacking it with the butt of your hand. Most bikes will
just shiver a moment when you do that and return to stable, but that sucker
would take a while to settle down. Dangerous on a gusty day - once had to
clip out of the damned thing at about 18mph on flat ground on a really windy
day (which was when it finally got the E-Bay boot). You could stand up,
clamp your knees on the top tube, all the usual stuff, but nothing other
than slowing to a crawl would finally get it to stop once it got going. Got
rid of it and got another bike; no more problem. Too bad the Giant sucked
going downhill because it was great going up 'em.

From admittedly anecdotal experience, I've had a number of people tell me
the medium TCR's were prone to that, but I also know a few guys that swear
theirs are fine. Did take note when I read something from pro racer John
Lieswyn recently about Healthnet getting their new TCR Advanced bikes for
'05 (even lighter); I had to laugh when he said the "lively" front end took
some getting used to. No sh#*!

For what it's worth, bikes with 73-degree head angles have always been a bit
prone to shimmying under me. To many other variables to make much of that,
but in 24 years of riding I never had a bike with either steeper or slacker
head angles do it. I can remember hitting 60mph comfortably (if briefly) on
a few steep descents with an old crit bike that had a 75 degree head angle,
and I can practically take a nap on my 72-degree angled Colnago at 50. Just
a bike-rider mismatch, or maybe some range of steering trail that just
doesn't work for me. 73 degrees is damn-near ubiquitous in mid-sized frames
though, and my current racebike has the same front end geometry as the
Giant. You can feel it trying to hunt back and forth every now and then;
just pointed it out to a riding mate recently while it was doing it. I was
standing on a mild descent, cranks flat with hands on the hoods watching it
snake a little under me. But with an oversized, laterally-wide top tube, I
guess it's sufficiently stiff to keep the oscillations from going ballistic
like the Giant. Gets your attention at times, but never makes it to scary
level.

Bottom line, treat your bike like a girlfriend; if you just can't get along,
call it splitsville and get another one. You'll both be better off with a
compatible companion! ;-)

SB

Greg SK? said:

It seems I get the death wobbles on most high speed descents on my
Giant TCR. The fork starts to shake shakes like crazy at anything
above 60 kms. I can control them by gripping the top tube between
my knees and unweighting my saddle but it's still scary and a
nuisance.

Quoted message said:

Any solutions for this with the TCR other than what I'm doing. Why
is it happening in the first place? Any recommendations for a road
bike that is death wobble free?

Without even worrying about the technical aspects of this occurrence,
if you never had this problem with your prior bicycle, then you would
probably be well served by either continuing riding that bicycle or
to buy a similar one. I haven't seen a picture of the bicycle in
question but it probably doesn't look much like your previous mount.
Besides that, I suspect you are not a short person and tall bicycles
have a greater tendency to shimmy than short ones.

Jobst Brandt
[email hidden]

Quoted message said:

Greg SK? said:

It seems I get the death wobbles on most high speed descents on my
Giant TCR.

I haven't seen a picture of the bicycle in
question but it probably doesn't look much like your previous mount.

Jobst Brandt
[email hidden]

http://www.giant-bicycle.com/us/030.000.000/030.000.000.asp?range=151
TCR carbon

http://www.giant-bicycle.com/us/030.000.000/030.000.000.asp?range=150
TCR aluminum

Quoted message said:

Bottom line, treat your bike like a girlfriend; if you just can't get

along,

Quoted message said:

call it splitsville and get another one. You'll both be better off with a
compatible companion! ;-)

SB

I agree.