Derailleur in spokes

As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! It sounds like the biggest stick ever is
caught in my rear spokes. I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. Let's see about that stick. To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: RD is a mangled
heap of twisted metal. Chain is all twisted. Cable is chewed up. So
far this isn't going to be too expensive. Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. The frame: Uh-oh. CF frame has cracked. BOO. :-(

OK, so much for my sob story. The real question I have is how the
heck do the RD go into the spokes in the first place? I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. I'm at a loss to explain how this tragedy happened. I
try to learn from my mistakes, but only if I know what the mistake
was. I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. Maybe I'll start carrying a chain tool
now.

Ken

On Jun 6, 12:11*pm, Ken wrote:
As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! *It sounds like the biggest stick ever is
caught in my rear spokes. *I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. *Let's see about that stick. *To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: *RD is a mangled
heap of twisted metal. *Chain is all twisted. *Cable is chewed up. *So
far this isn't going to be too expensive. *Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. *The frame: *Uh-oh. *CF frame has cracked. *BOO. *:-(

OK, so much for my sob story. *The real question I have is how the
heck do the RD go into the spokes in the first place? *I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? *I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. *I'm at a loss to explain how this tragedy happened. *I
try to learn from my mistakes, but only if I know what the mistake
was. *I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. *I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. *I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. *No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. *It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. *Maybe I'll start carrying a chain tool
now.

Ken

Is the derailleur fixing bolt securely in the broken off bit of
hanger? Was the hanger secure in the frame? Was your wheel skewer
loose? Who monkeyed with the bike last?

Op 6-6-2011 19:11, Ken schreef:
As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! It sounds like the biggest stick ever is
caught in my rear spokes. I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. Let's see about that stick. To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: RD is a mangled
heap of twisted metal. Chain is all twisted. Cable is chewed up. So
far this isn't going to be too expensive. Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. The frame: Uh-oh. CF frame has cracked. BOO. :-(

OK, so much for my sob story. The real question I have is how the
heck do the RD go into the spokes in the first place? I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. I'm at a loss to explain how this tragedy happened. I
try to learn from my mistakes, but only if I know what the mistake
was. I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. Maybe I'll start carrying a chain tool
now.

Ken


Your derailleur wasn't ripped of it came loose, the bolt broke, the
hanger broke/came loose. etc. When something is on the point of breaking
it is likely it breaks when you are shifting.


Lou

Ken wrote:
As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! It sounds like the biggest stick ever is
caught in my rear spokes. I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. Let's see about that stick. To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: RD is a mangled
heap of twisted metal. Chain is all twisted. Cable is chewed up. So
far this isn't going to be too expensive. Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. The frame: Uh-oh. CF frame has cracked. BOO. :-(

OK, so much for my sob story. The real question I have is how the
heck do the RD go into the spokes in the first place? I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. I'm at a loss to explain how this tragedy happened. I
try to learn from my mistakes, but only if I know what the mistake
was. I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. Maybe I'll start carrying a chain tool
now.

Ken

I carry a small chain tool from Park (works great) and a quick link. I
haven't needed them myself for a while but I have stopped to fix similar
problems for others. Good idea!

Ken wrote:
As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! It sounds like the biggest stick ever is
caught in my rear spokes. I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. Let's see about that stick. To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: RD is a mangled
heap of twisted metal. Chain is all twisted. Cable is chewed up. So
far this isn't going to be too expensive. Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. The frame: Uh-oh. CF frame has cracked. BOO. :-(

OK, so much for my sob story. The real question I have is how the
heck do the RD go into the spokes in the first place? I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. I'm at a loss to explain how this tragedy happened. I
try to learn from my mistakes, but only if I know what the mistake
was. I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. Maybe I'll start carrying a chain tool
now.


I don't know, but since it wasn't a typical overshift into
spokes, one possible scenario is a longish chain which can
slip off the lower roller and jam aside the cage, taking the
whole rear changer up and over the cassette. At that point,
either denting the right seatstay or engaging the spokes is
a random choice.

http://www.yellowjersey.org/borga.html

I can see the loss of the lower roller (bolt loose) as
another possible scenario. Or, as you noted, some road debris.

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

Ken wrote:

As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! *It sounds like the biggest stick ever is
caught in my rear spokes. *
[...]
Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. *It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

There is a simple, lightweight, reliable and inexpensive device that
prevents just this sort of failure. It's called a spoke protector,
and it works. It's cheaper than buying a new bike frame (or
replacement dropout) and sundry parts every so often.

I know who among my customers is most likely to need one. But a good
rule of thumb is, if you suspect you need one, you do. If you have no
idea whether or not you need one, you do. And if you aren't clear
about what a spoke protector is for, you need one.

The spoke protector has been unduly maligned. It is to chronic or
occasional obliviousness what fenders are to rain. And everyone is at
least occasionally oblivious.

Chalo

On 6/7/2011 2:21 AM, Çhâlõ Çólîñã wrote:
Ken wrote:

As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! �It sounds like the biggest stick ever is
caught in my rear spokes. �
[...]
Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. �It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

There is a simple, lightweight, reliable and inexpensive device that
prevents just this sort of failure. It's called a spoke protector,
and it works. It's cheaper than buying a new bike frame (or
replacement dropout) and sundry parts every so often.

I know who among my customers is most likely to need one. But a good
rule of thumb is, if you suspect you need one, you do. If you have no
idea whether or not you need one, you do. And if you aren't clear
about what a spoke protector is for, you need one.

The spoke protector has been unduly maligned. It is to chronic or
occasional obliviousness what fenders are to rain. And everyone is at
least occasionally oblivious.

Or one could use full disc wheel covers that would serve the same
purpose, while also preventing squirrel intrusion and improving
aerodynamics.

--
Tºm Shermªn - 42.435731,-83.985007
I am a vehicular cyclist.

TÑ„m ShermÑŒn wrote:

Çhâlõ Çólîñã wrote:

The spoke protector has been unduly maligned. Â*It is to chronic or
occasional obliviousness what fenders are to rain. Â*And everyone is at
least occasionally oblivious.

Or one could use full disc wheel covers that would serve the same
purpose, while also preventing squirrel intrusion and improving
aerodynamics.

Those are full-coverage, all-wheel spoke protectors for the maximally
oblivious.

Chalo

On 6/7/2011 4:49 PM, James wrote:
On 7/06/2011 8:59 PM, Tºm Shermªn °_° wrote:

Or one could use full disc wheel covers that would serve the same
purpose, while also preventing squirrel intrusion and improving
aerodynamics.

Bad in cross winds.


In ISO 571-mm and ISO 622-mm sizes, yes.

In ISO 305-mm and ISO 406-mm sizes, not so much.

--
Tºm Shermªn - 42.435731,-83.985007
I am a vehicular cyclist.

On Jun 6, 6:11*pm, Ken wrote:
As I had just finished a short climb on a small hill the other day, I
started down the other side, shifted to a higher gear (smaller
cassette gear), and Wham! *It sounds like the biggest stick ever is
caught in my rear spokes. *I realize I'm rapidly coming to a stop, so
fast that in my bewilderment about the object caught in my spokes I
fail to get unclipped and do the embarrasing fallover trick.

Nevermind, I'm fine. *Let's see about that stick. *To my astonishment,
it's the RD that's caught in the spokes, has been ripped off, and
along with the chain and cable is all wrapped up between the spokes
and the rear seatstay. OK, let's assess the damage: *RD is a mangled
heap of twisted metal. *Chain is all twisted. *Cable is chewed up. *So
far this isn't going to be too expensive. *Spokes are a bit abraded,
but nothing too terrible, maybe I can just replace the spokes on the
drive side. *The frame: *Uh-oh. *CF frame has cracked. *BOO. *:-(

OK, so much for my sob story. *The real question I have is how the
heck do the RD go into the spokes in the first place? *I was somwhere
in the middle of the cassette, shifting to smaller gears further from
the wheel, and the RD gets caught? *I don't recall running over
anything of significance, didn't hit any potholes, nothing out of the
ordinary other than shifter to a higher gear as you would after you
crest a hill. *I'm at a loss to explain how this tragedy happened. *I
try to learn from my mistakes, but only if I know what the mistake
was. *I don't think the hanger had been bent putting the pulleys
perilously close to the spokes. *I had cleaned and lubed the chain
just before this ride, and I didn't notice anything unusual about the
RD at the time. *I only stopped once at the turn-around point in my
ride and gently leaned the bike against a tree like I've done a
thousand times before, so I can't imagine that I bent the RD then. *No
other falls or anything alse of consequence that I can imagine to
cause a bent hanger and put myself in danger.

Once I got home I did a little failure analysis, and matched up the
two halves of the RD hanger, the piece on the RD, and the piece left
on the frame. *It is clear that the hanger was bent about 90 degrees
before finally breaking, indicating that the RD was firmly planted in
the spokes and being dragged around with the wheel until it hit the
seatstay.

As an aside, I realized that if I had a chain tool with me, along with
a shimano pin, I could have turned the bike into a single speed for
the rest of the ride home and a cell phone would not have needed to be
the tool that got me home. *Maybe I'll start carrying a chain tool
now.

Ken

Sounds like a chain jam or a top spring failure causing the derailleur
cage to swing up into the cogs at which point the whole lot gets
dragged around and into the spokes. It's one of those theoretical
problems "just never happens". It's a crap design, get a Nuovo Record
and base your gearing around a half step and it will NEVER happen.
I'd have prefered to have seen a spoke failure there, that's what
happened to me when a Dura-ace EX got locked on a polythene bag.
Five spokes snapped and I stayed on the bike. The steel hanger was
bent off true but the bike was still just ridable after the bag was
removed. Even my tyre didn't suffer a flat spot. Straightening the
hanger and replacing the five spokes was a cheap repair in comparison
to your damage.
These derailleurs have this inherrent problem, get an old style 36
spoke wheel for your rear (with thin spokes) if you wish to continue
with this style derailleur with minimised risk, or just go slower.
Consider spokes as a sacrificial comodity to improve your safety.