Ultegra Rear Derailleur Total Failure(long)

Joel Rose said:

On a recent road ride, after approx. 48km of riding, I noticed what sounded
like my chain popping off from the front chain ring while coming to a stop.
To my horror when I stopped suddenly and looked over my bike, my rear
derailleur had actually SNAPPED in two, breaking at the lower pivot(?), just
below where it says Ultegra on the derailleur facing. The lower half of the
derailleur was wedged into my spokes with the chain still attached to the
small rings and the upper half was still attached to the derailleur hanger
which was bent inward quite badly.

This blows me away as I wasn't even under heavy pedaling load when this
failure happened, I was gearing down for the stop...All I can ask is "What gives??"

Has this ever happened to anyone else in forum land?

Yes, it's actually very common, and has probably happened to most of us
on this list at least once.

The usual scenario starts with the derailer getting banged, bending the
hanger. This can happen surprisingly easily, sometimes from the bike
falling over, or while putting it into a car, or having a swinging door
bang into it.

This impact bends the hanger, and will usually cause some degradation in
shifting, but it may not be immediately obvious that there's a problem.

Typically, with this sort of damage, the derailer won't shift onto the
smallest sprocket, which is no big deal.

What is a big deal is that it can now shift _past_ the big sprocket, and
get caught by the spokes of the moving wheel. This happens when you try
to shift down to the biggest sprocket. The fact that it "wasn't even
under heavy pedaling load" isn't relevant, because it was the moving
spokes that snagged the derailer cage and did the more severe damage.

The main way to prevent this is to be very careful not to let anything
bump into the rear derailer. Entry level bikes often have big metal or
plastic discs behind the sprocket cluster to prevent a bent derailer
from snagging the spokes, but it is quite unfashionable to have one of
these on a high-end bike.

Sheldon "Familiar Story" Brown
+----------------------------------------------------+
| I admit that reason is a small and feeble flame, |
| a flickering torch by stumblers carried in the |
| star-less night, -- blown and flared by passion's |
| storm, -- and yet, it is the only light. |
| Extinguish that, and nought remains. |
| -- Robert Green Ingersoll |
+----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Joel Rose said:

On a recent road ride, after approx. 48km of riding, I noticed what sounded
like my chain popping off from the front chain ring while coming to a stop.
To my horror when I stopped suddenly and looked over my bike, my rear
derailleur had actually SNAPPED in two, breaking at the lower pivot(?), just
below where it says Ultegra on the derailleur facing. The lower half of the
derailleur was wedged into my spokes with the chain still attached to the
small rings and the upper half was still attached to the derailleur hanger
which was bent inward quite badly.

This blows me away as I wasn't even under heavy pedaling load when this
failure happened, I was gearing down for the stop. The derailleur is about 4
years old, an RD-6500 9-speed. My bike is a Colnago Asso with a badly
damaged hanger and slightly bent chain stay. All I can ask is "What gives??"

Has this ever happened to anyone else in forum land?

Is the chain partially broken? Almost this exact same failure happened
to me when one of the side plates on my chain bent out, but didn't
detach. It jammed up really nicely in the derailleur and took out out my
derailleur, and a couple spokes. I ended up single-speeding home from
work.

--
Dane Jackson - z u v e m b i @ u n i x b i g o t s . o r g
"You know you're a loser when you try to sell your soul to
the devil and he asks you for your credit card number."

Sheldon Brown said:

Joel Rose said:

On a recent road ride, after approx. 48km of riding, I noticed what sounded
like my chain popping off from the front chain ring while coming to a stop.
To my horror when I stopped suddenly and looked over my bike, my rear
derailleur had actually SNAPPED in two, breaking at the lower pivot(?), just
below where it says Ultegra on the derailleur facing. The lower half of the
derailleur was wedged into my spokes with the chain still attached to the
small rings and the upper half was still attached to the derailleur hanger
which was bent inward quite badly.

This blows me away as I wasn't even under heavy pedaling load when this
failure happened, I was gearing down for the stop...All I can ask is "What gives??"

Has this ever happened to anyone else in forum land?

Yes, it's actually very common, and has probably happened to most of us
on this list at least once.

The usual scenario starts with the derailer getting banged, bending the
hanger. This can happen surprisingly easily, sometimes from the bike
falling over, or while putting it into a car, or having a swinging door
bang into it.

This impact bends the hanger, and will usually cause some degradation in
shifting, but it may not be immediately obvious that there's a problem.

Typically, with this sort of damage, the derailer won't shift onto the
smallest sprocket, which is no big deal.

What is a big deal is that it can now shift _past_ the big sprocket, and
get caught by the spokes of the moving wheel. This happens when you try
to shift down to the biggest sprocket. The fact that it "wasn't even
under heavy pedaling load" isn't relevant, because it was the moving
spokes that snagged the derailer cage and did the more severe damage.

The main way to prevent this is to be very careful not to let anything
bump into the rear derailer. Entry level bikes often have big metal or
plastic discs behind the sprocket cluster to prevent a bent derailer
from snagging the spokes, but it is quite unfashionable to have one of
these on a high-end bike.

Sheldon "Familiar Story" Brown
+----------------------------------------------------+
| I admit that reason is a small and feeble flame, |
| a flickering torch by stumblers carried in the |
| star-less night, -- blown and flared by passion's |
| storm, -- and yet, it is the only light. |
| Extinguish that, and nought remains. |
| -- Robert Green Ingersoll |
+----------------------------------------------------+

Can one buy these discs as an add-on, ones with a slit or something so
as to not have to remove parts on the wheel? Fashion? Not using one of
these seems to me an advertisement of one's imbecility.

Great Ingersoll quote. Hope to visit his birthplace/museum this Summer
in NY state.

Ted Morton

Theodore Morton said:

Can one buy these discs as an add-on, ones with a slit or something so
as to not have to remove parts on the wheel? Fashion? Not using one of
these seems to me an advertisement of one's imbecility.

Ted Morton

Yes, spoke protectors are offered in the after market and come in different
configurations for different spoke patterns.

Theodore Morton said:

Sheldon Brown said:

Joel Rose said:

On a recent road ride, after approx. 48km of riding, I noticed what sounded
like my chain popping off from the front chain ring while coming to a stop.
To my horror when I stopped suddenly and looked over my bike, my rear
derailleur had actually SNAPPED in two, breaking at the lower pivot(?), just
below where it says Ultegra on the derailleur facing. The lower half of the
derailleur was wedged into my spokes with the chain still attached to the
small rings and the upper half was still attached to the derailleur hanger
which was bent inward quite badly.

This blows me away as I wasn't even under heavy pedaling load when this
failure happened, I was gearing down for the stop...All I can ask is "What gives??"

Has this ever happened to anyone else in forum land?

Yes, it's actually very common, and has probably happened to most of us
on this list at least once.

The usual scenario starts with the derailer getting banged, bending the
hanger. This can happen surprisingly easily, sometimes from the bike
falling over, or while putting it into a car, or having a swinging door
bang into it.

This impact bends the hanger, and will usually cause some degradation in
shifting, but it may not be immediately obvious that there's a problem.

Typically, with this sort of damage, the derailer won't shift onto the
smallest sprocket, which is no big deal.

What is a big deal is that it can now shift _past_ the big sprocket, and
get caught by the spokes of the moving wheel. This happens when you try
to shift down to the biggest sprocket. The fact that it "wasn't even
under heavy pedaling load" isn't relevant, because it was the moving
spokes that snagged the derailer cage and did the more severe damage.

The main way to prevent this is to be very careful not to let anything
bump into the rear derailer. Entry level bikes often have big metal or
plastic discs behind the sprocket cluster to prevent a bent derailer
from snagging the spokes, but it is quite unfashionable to have one of
these on a high-end bike.

Sheldon "Familiar Story" Brown
+----------------------------------------------------+
| I admit that reason is a small and feeble flame, |
| a flickering torch by stumblers carried in the |
| star-less night, -- blown and flared by passion's |
| storm, -- and yet, it is the only light. |
| Extinguish that, and nought remains. |
| -- Robert Green Ingersoll |
+----------------------------------------------------+

Can one buy these discs as an add-on, ones with a slit or something so
as to not have to remove parts on the wheel? Fashion? Not using one of
these seems to me an advertisement of one's imbecility.

Great Ingersoll quote. Hope to visit his birthplace/museum this Summer
in NY state.

Ted Morton

Dear Ted,

Sorry, but all spoke protectors all require removing the
rear gear cluster for installation.

You can buy them in three main models--3 prong for 32-spoke
freehub wheels, 4 prong for 36-spoke freehubs, and no-prong
for older freewheels:

http://www.biketoolsetc.com/index.cgi?id=609552072011&c=Repair%20Parts&sc=Freehubs%20and%20Freewheels&tc=Spoke%20Protectors

The size varies according to how many teeth are expected on
the largest rear sprocket.

Carl Fogel

Your diagnosis is actually what my LBS wrench-man suggested. So now my bike
is in sick bay for most of the upcoming week. Looks like a new drivetrain.

In an odd bit of irony, you quote a man that shares the same last name as
the town in which I work - Ingersoll,ON.

Joel
"Sheldon Brown" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Joel Rose said:

On a recent road ride, after approx. 48km of riding, I noticed what
sounded like my chain popping off from the front chain ring while coming
to a stop. To my horror when I stopped suddenly and looked over my bike,
my rear derailleur had actually SNAPPED in two, breaking at the lower
pivot(?), just below where it says Ultegra on the derailleur facing. The
lower half of the derailleur was wedged into my spokes with the chain
still attached to the small rings and the upper half was still attached
to the derailleur hanger which was bent inward quite badly.

This blows me away as I wasn't even under heavy pedaling load when this
failure happened, I was gearing down for the stop...All I can ask is
"What gives??"

Has this ever happened to anyone else in forum land?

Yes, it's actually very common, and has probably happened to most of us
on this list at least once.

The usual scenario starts with the derailer getting banged, bending the
hanger. This can happen surprisingly easily, sometimes from the bike
falling over, or while putting it into a car, or having a swinging door
bang into it.

This impact bends the hanger, and will usually cause some degradation in
shifting, but it may not be immediately obvious that there's a problem.

Typically, with this sort of damage, the derailer won't shift onto the
smallest sprocket, which is no big deal.

What is a big deal is that it can now shift _past_ the big sprocket, and
get caught by the spokes of the moving wheel. This happens when you try
to shift down to the biggest sprocket. The fact that it "wasn't even
under heavy pedaling load" isn't relevant, because it was the moving
spokes that snagged the derailer cage and did the more severe damage.

The main way to prevent this is to be very careful not to let anything
bump into the rear derailer. Entry level bikes often have big metal or
plastic discs behind the sprocket cluster to prevent a bent derailer from
snagging the spokes, but it is quite unfashionable to have one of these on
a high-end bike.

Sheldon "Familiar Story" Brown
+----------------------------------------------------+
| I admit that reason is a small and feeble flame, |
| a flickering torch by stumblers carried in the |
| star-less night, -- blown and flared by passion's |
| storm, -- and yet, it is the only light. |
| Extinguish that, and nought remains. |
| -- Robert Green Ingersoll |
+----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Dane Jackson said:

Is the chain partially broken? Almost this exact same failure happened
to me when one of the side plates on my chain bent out, but didn't

I had the exact thing happen (Ultegra STI/Ult rear der). I had attributed it to the SRAM link I had put on a Shimano chain (which I haven't done since), but perhaps not totally that. Nasty noise, got off bike, and the chain was apart at the link and the derailleur hanger broken off and cable housing nastily frayed. Road home single speed like you. Derailleur seemed to be fine afterward, but perhaps Sheldon's diagnosis will hold true for mine too.

Interesting hearing about similar stories!