Rear Derailleur

I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt..

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.

On Monday, May 10, 2021 at 9:59:14 AM UTC-7, Tom Kunich wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.

Although there wasn't anything close on Ebay, I went to Wheels manufacturing in Colorado and it was one of their common hangers - type 57. Ordered it and it should be here in 4-5 days. The world is a whole lot better place with American companies. Too bad that Biden and the Democrats think otherwise..

On Monday, May 10, 2021 at 11:59:40 AM UTC-7, Tom Kunich wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, Tom Kunich wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.
Although there wasn't anything close on Ebay, I went to Wheels manufacturing in Colorado and it was one of their common hangers - type 57. Ordered it and it should be here in 4-5 days. The world is a whole lot better place with American companies. Too bad that Biden and the Democrats think otherwise.

Brandford Bikes has a supply of Campy parts so I ordered replacement parts for the Centaur derailleur I took apart to repair the Chorus. This will give me a spare rear derailleur again. The parts on lower grade Campy tend to be cast aluminum rather than formed steel parts that take up less room and are less likely to break. So after the Derailleur hanger gets here the Brandford bike parts will probably arrive around the same time and I'll be back to the position I was in before that yesterday ride.

On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.

It sounds like you pulled the guide pulley into the cassette and the other damage followed and not vice versa. That can happen under certain unfortunate circumstances.

-- Jay Beattie.

On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the other damage followed and not vice versa. That can happen under certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that is what I thought too. Until I analyzed it. The stop on the rear derailleur with is a small sheet steel washer-like mechanism that keeps the derailleur from rotating past the stop. Without that stop the idler pulley was pulled into the cassette and the entire mechanism was locked up solid. I had to pull the rear wheel out to loosen the chain enough to free everything up. I assumed that the fancy ultra light and ultra low friction idler pulley had simply shattered but it probably was not the source of the failure. That wouldn't have caused that type of failure. It was simply metal fatigue in the steel stop washer. If you have Centaur or better Campy rear derailleur you can see it on the backside of the derailleur mounting bolt.

I'm lucky that I could get it working well enough to ride the remaining 7 miles home.

On Monday, May 10, 2021 at 4:51:13 PM UTC-7, wrote:
On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the other damage followed and not vice versa. That can happen under certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that is what I thought too.

Sure it can, and it happens with fair regularity on MTBs. It can be a b-screw screw-up, limit screw screw-up, worn chain, cassette, chainrings -- a stick, rock. It can even be caused by a shift and a bump. I have never heard of the b-screw tab breaking, but maybe that happens on Campy derailleurs -- and if so, that is a major design FU, particularly considering the consequences.

Until I analyzed it. The stop on the rear derailleur with is a small sheet steel washer-like mechanism that keeps the derailleur from rotating past the stop. Without that stop the idler pulley was pulled into the cassette and the entire mechanism was locked up solid.

FYI, your typical pully choices are "upper or lower" or "guide pulley" (upper) or "tension pulley." (lower). I don't know what an idler pulley is on a derailleur.

-- Jay Beattie.

On 5/10/2021 8:22 PM, jbeattie wrote:
On Monday, May 10, 2021 at 4:51:13 PM UTC-7, wrote:
On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the steepest part was only about 9%. For some reason I was dog tired and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most extent, the rear derailleur idler pully exploded. I assumed that it was the roller bearing idler pulley but working on it what happened was the the sheet metal rotational limit piece on the derailleur appears to have broken off which caused the pulley to be pulled into the cassette which broke it and this entire thing locked up the whole drive train which bent the drop out. So I have to get a replacement for that. After removing the rear derailleur it will not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the other damage followed and not vice versa. That can happen under certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that is what I thought too.

Sure it can, and it happens with fair regularity on MTBs. It can be a b-screw screw-up, limit screw screw-up, worn chain, cassette, chainrings -- a stick, rock. It can even be caused by a shift and a bump. I have never heard of the b-screw tab breaking, but maybe that happens on Campy derailleurs -- and if so, that is a major design FU, particularly considering the consequences.

Until I analyzed it. The stop on the rear derailleur with is a small sheet steel washer-like mechanism that keeps the derailleur from rotating past the stop. Without that stop the idler pulley was pulled into the cassette and the entire mechanism was locked up solid.

FYI, your typical pully choices are "upper or lower" or "guide pulley" (upper) or "tension pulley." (lower). I don't know what an idler pulley is on a derailleur.

-- Jay Beattie.


And it's simple to avoid.
Finish any gear adjustment with this test:
http://www.yellowjersey.org/photosfr...t/gearchek.jpg

image from Canada, miketechinfo.com

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

On 5/10/2021 9:42 PM, AMuzi wrote:
On 5/10/2021 8:22 PM, jbeattie wrote:
On Monday, May 10, 2021 at 4:51:13 PM UTC-7, wrote:
On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the
steepest part was only about 9%. For some reason I was dog tired
and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most
extent, the rear derailleur idler pully exploded. I assumed that it
was the roller bearing idler pulley but working on it what happened
was the the sheet metal rotational limit piece on the derailleur
appears to have broken off which caused the pulley to be pulled
into the cassette which broke it and this entire thing locked up
the whole drive train which bent the drop out. So I have to get a
replacement for that. After removing the rear derailleur it will
not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the
other damage followed and not vice versa. That can happen under
certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that
is what I thought too.

Sure it can, and it happens with fair regularity on MTBs.Â*Â* It can be
a b-screw screw-up, limit screw screw-up, worn chain, cassette,
chainrings -- a stick, rock.Â* It can even be caused by a shift and a
bump.Â*Â* I have never heard of the b-screw tab breaking, but maybe that
happens on Campy derailleurs -- and if so, that is a major design FU,
particularly considering the consequences.

Until I analyzed it. The stop on the rear derailleur with is a small
sheet steel washer-like mechanism that keeps the derailleur from
rotating past the stop. Without that stop the idler pulley was pulled
into the cassette and the entire mechanism was locked up solid.

FYI, your typical pully choices are "upper or lower" or "guide pulley"
(upper) orÂ* "tension pulley." (lower).Â* I don't know what an idler
pulley is on a derailleur.

Â* -- Jay Beattie.


And it's simple to avoid.
Finish any gear adjustment with this test:
http://www.yellowjersey.org/photosfr...t/gearchek.jpg

image from Canada, miketechinfo.com

I think Tom needs to hire a better mechanic. It seems like about a
quarter of his posts are about bike wrenching screw-ups.


--
- Frank Krygowski

On Monday, May 10, 2021 at 7:09:57 PM UTC-7, Frank Krygowski wrote:
On 5/10/2021 9:42 PM, AMuzi wrote:
On 5/10/2021 8:22 PM, jbeattie wrote:
On Monday, May 10, 2021 at 4:51:13 PM UTC-7, wrote:
On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the
steepest part was only about 9%. For some reason I was dog tired
and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most
extent, the rear derailleur idler pully exploded. I assumed that it
was the roller bearing idler pulley but working on it what happened
was the the sheet metal rotational limit piece on the derailleur
appears to have broken off which caused the pulley to be pulled
into the cassette which broke it and this entire thing locked up
the whole drive train which bent the drop out. So I have to get a
replacement for that. After removing the rear derailleur it will
not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the
other damage followed and not vice versa. That can happen under
certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that
is what I thought too.

Sure it can, and it happens with fair regularity on MTBs. It can be
a b-screw screw-up, limit screw screw-up, worn chain, cassette,
chainrings -- a stick, rock. It can even be caused by a shift and a
bump. I have never heard of the b-screw tab breaking, but maybe that
happens on Campy derailleurs -- and if so, that is a major design FU,
particularly considering the consequences.

Until I analyzed it. The stop on the rear derailleur with is a small
sheet steel washer-like mechanism that keeps the derailleur from
rotating past the stop. Without that stop the idler pulley was pulled
into the cassette and the entire mechanism was locked up solid.

FYI, your typical pully choices are "upper or lower" or "guide pulley"
(upper) or "tension pulley." (lower). I don't know what an idler
pulley is on a derailleur.

-- Jay Beattie.


And it's simple to avoid.
Finish any gear adjustment with this test:
http://www.yellowjersey.org/photosfr...t/gearchek.jpg

image from Canada, miketechinfo.com
I think Tom needs to hire a better mechanic. It seems like about a
quarter of his posts are about bike wrenching screw-ups.

And yet as a supposed mechanical engineer you don't even know how to hold an Allen wrench. I find it humorous that people who haven't seen a thing in their lives are so ready to tell others how to do things. Jay is telling us that since things happen on an MTB with a 42 tooth cassette they happen all the time on a Campy Record bike with a 28 tooth.

If it wasn't so comical you guys would be nothing more than pitiful.

On 5/11/2021 8:41 AM, Tom Kunich wrote:
On Monday, May 10, 2021 at 7:09:57 PM UTC-7, Frank Krygowski wrote:
On 5/10/2021 9:42 PM, AMuzi wrote:
On 5/10/2021 8:22 PM, jbeattie wrote:
On Monday, May 10, 2021 at 4:51:13 PM UTC-7, wrote:
On Monday, May 10, 2021 at 4:19:53 PM UTC-7, jbeattie wrote:
On Monday, May 10, 2021 at 9:59:14 AM UTC-7, wrote:
I did a climbing ride sort of - it was less that 1000 feet and the
steepest part was only about 9%. For some reason I was dog tired
and it really hurt.

3/4ths of the way in to the ride and luckily downhill to most
extent, the rear derailleur idler pully exploded. I assumed that it
was the roller bearing idler pulley but working on it what happened
was the the sheet metal rotational limit piece on the derailleur
appears to have broken off which caused the pulley to be pulled
into the cassette which broke it and this entire thing locked up
the whole drive train which bent the drop out. So I have to get a
replacement for that. After removing the rear derailleur it will
not thread back in.

Finding a replacement ought to be a whole lot of fun.
It sounds like you pulled the guide pulley into the cassette and the
other damage followed and not vice versa. That can happen under
certain unfortunate circumstances.

The rear derailleur cannot be "pulled into the cassette" though that
is what I thought too.

Sure it can, and it happens with fair regularity on MTBs. It can be
a b-screw screw-up, limit screw screw-up, worn chain, cassette,
chainrings -- a stick, rock. It can even be caused by a shift and a
bump. I have never heard of the b-screw tab breaking, but maybe that
happens on Campy derailleurs -- and if so, that is a major design FU,
particularly considering the consequences.

Until I analyzed it. The stop on the rear derailleur with is a small
sheet steel washer-like mechanism that keeps the derailleur from
rotating past the stop. Without that stop the idler pulley was pulled
into the cassette and the entire mechanism was locked up solid.

FYI, your typical pully choices are "upper or lower" or "guide pulley"
(upper) or "tension pulley." (lower). I don't know what an idler
pulley is on a derailleur.

-- Jay Beattie.


And it's simple to avoid.
Finish any gear adjustment with this test:
http://www.yellowjersey.org/photosfr...t/gearchek.jpg

image from Canada, miketechinfo.com
I think Tom needs to hire a better mechanic. It seems like about a
quarter of his posts are about bike wrenching screw-ups.

And yet as a supposed mechanical engineer you don't even know how to hold an Allen wrench. I find it humorous that people who haven't seen a thing in their lives are so ready to tell others how to do things. Jay is telling us that since things happen on an MTB with a 42 tooth cassette they happen all the time on a Campy Record bike with a 28 tooth.

If it wasn't so comical you guys would be nothing more than pitiful.


Is there a 'wrong' way to hold an allen wrench? In two
tentacles rather than three? What?

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