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Bad rear derailleur???



 
 
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  #11  
Old August 12th 19, 08:46 PM posted to rec.bicycles.tech
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Default Bad rear derailleur???

On Monday, August 12, 2019 at 2:01:55 PM UTC-5, Tom Kunich wrote:
On Sunday, August 11, 2019 at 2:40:06 PM UTC-7, wrote:
On Sunday, August 11, 2019 at 3:22:40 PM UTC-5, wrote:
Did a gravel ride on Saturday morning. 43 miles total, about 30 was gravel. Lot of rough gravel, very few hard, smooth, compacted stripes on the gravel road. I'm accustomed to gravel roads having well worn tracks where the cars drive. Nope.

For the final 6 miles of pavement, the rear derailleur did not work. When shifting up and down the cassette, it did not want to find the cog and jumped around a lot. I'd click and nothing happened. I'd click again and nothing happened. I'd click again and it would sort of grind and jump around looking for a cog. So I'd have to shift a bunch to get it to settle down into one cog. It did not go thunk into the next cog when shifting the STI levers.

And when shifting down to the small ring, the chain drooped on the bottom. The spring in the rear derailleur to pull it backwards and take up the chain slack was not working correctly. It wasn't strong enough to pull backwards with enough force. Had to ride the big ring only for the final miles, with the bad between cog shifting too. I basically had a single speed.

I cleaned the bike with the garden hose afterwards thinking maybe it was just the gravel dust that ruined everything. Have not had a chance to test the shifting in the basement shop. Will also try taking the derailleur off and re-lubing everything and really cleaning everything with gasoline.. And spraying lubricant into the STI levers. And oiling the cables.

Questions: Can any 10 speed Shimano rear derailleur work? Dura Ace, Ultegra, 105, Tiagra, AND all of the mountain bike rear derailleurs? Nashbar has a lot of 10 speed rear derailleurs for sale. Thinking maybe a mountain will be better than road for gravel and mud? Its a short cage rear derailleur. But I was thinking maybe going medium or long if I could. Yes, no? I've never noticed any shifting difference between derailleur lengths. Current rings are 46-36 with 12-28 cassette. But maybe I will want to go 46-33 rings (110mm bcd five arm crank) and 11-32 or 11-34 ten speed cassette. Make it my second mountain climbing bike. But its a heavy steel frame....



Did some work on the bike. Took the cable, chain, rear derailleur off. The bottom spring in the rear derailleur that pulls the pulley cage backwards to take up chain slack, is bad. Spring does not pull back much at all.. No tension, resistance on the pulley cage. Pulley cage does not snap back. I cannot see any way to get access to this spring for replacement. Or repair if its even possible to repair springs? So it looks like a new rear derailleur is needed.

Mountain or road? Shimano of course. But are mountain derailleurs better at resisting dust infiltration and not working? 10 speed. Are road 10 STI and mountain 10 speed rear derailleurs compatible? I know Shimano stopped making road and mountain work together some time in the past.

Short again, or go up to medium/long to get more capacity if I ever expand gearing?


You may want to look more closely at the derailleur. It is more likely that there is dirt or grit in the cage rotation that is overcoming the return spring.


Cage rotation? Do you mean the bottom spring on the rear derailleur that is all enclosed that pulls the cage forwards and backwards to take up chain slack? I agree it is now all filled up with gravel dust and the spring no longer pulls the cage forward and backward. And I don't see any way of cleaning it since its all enclosed. Not sure how it got all filled up with gravel dust since its all enclosed either. But I guess dust finds its way in somehow.
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  #13  
Old August 13th 19, 03:56 AM posted to rec.bicycles.tech
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Default Bad rear derailleur???

On Monday, August 12, 2019 at 9:15:27 AM UTC-5, AMuzi wrote:

Get your eye behind the rear changer and see if the cage is
parallel to the chainrings.

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


Gosh darn Andy, I'm beginning to suspect maybe you know what you are talking about. I put my Park rear derailleur hanger tool on the rear hanger. And G-d D-mn it was so crooked. I got it back to being perfectly aligned. Its a steel hanger that is welded right onto the steel frame. So easy to bend it right. With the hanger being so bent, I can't figure out how rear shifting was perfectly fine for the first 30 miles of the ride. All shifts perfect. I'd think a crooked rear hanger would not shift right.
  #14  
Old August 13th 19, 03:18 PM posted to rec.bicycles.tech
JBeattie
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Default Bad rear derailleur???

On Monday, August 12, 2019 at 7:56:53 PM UTC-7, wrote:
On Monday, August 12, 2019 at 9:15:27 AM UTC-5, AMuzi wrote:

Get your eye behind the rear changer and see if the cage is
parallel to the chainrings.

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


Gosh darn Andy, I'm beginning to suspect maybe you know what you are talking about. I put my Park rear derailleur hanger tool on the rear hanger. And G-d D-mn it was so crooked. I got it back to being perfectly aligned. Its a steel hanger that is welded right onto the steel frame. So easy to bend it right. With the hanger being so bent, I can't figure out how rear shifting was perfectly fine for the first 30 miles of the ride. All shifts perfect. I'd think a crooked rear hanger would not shift right.


That's why a crooked derailleur hanger doesn't make sense -- it doesn't just occur unless you dropped the bike or hit something. An outside possibility is that you got something into the derailleur that dragged it into the wheel and bent the hanger, but when that happens, the derailleur is usually ruined and wound around your cassettes or in the spokes. My first thought was that your cable was in the process of failing.


-- Jay Beattie.
  #15  
Old August 13th 19, 03:30 PM posted to rec.bicycles.tech
Joerg[_2_]
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Default Bad rear derailleur???

On 2019-08-11 19:09, Chalo wrote:
Note that Shimano road and MTB 10 speed derailleurs have different
pull ratios. Rear derailleurs and shifters are miscible up to 9
speed.


Not really. I have a 7-speed set-up on my road bike and, after a crash
and restore, wanted to use the Alivio shifters from a 7-speed MTB on my
road bike. Measured the cable pull ration and it was almost 10%
different. So I still have friction shifters on the road bike until I
transplant the derailer. Which won't be easy since I have a 40T cog in back.

--
Regards, Joerg

http://www.analogconsultants.com/
  #16  
Old August 13th 19, 03:35 PM posted to rec.bicycles.tech
Joerg[_2_]
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Default Bad rear derailleur???

On 2019-08-13 07:18, jbeattie wrote:
On Monday, August 12, 2019 at 7:56:53 PM UTC-7,
wrote:
On Monday, August 12, 2019 at 9:15:27 AM UTC-5, AMuzi wrote:

Get your eye behind the rear changer and see if the cage is
parallel to the chainrings.

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


Gosh darn Andy, I'm beginning to suspect maybe you know what you
are talking about. I put my Park rear derailleur hanger tool on
the rear hanger. And G-d D-mn it was so crooked. I got it back to
being perfectly aligned. Its a steel hanger that is welded right
onto the steel frame. So easy to bend it right. With the hanger
being so bent, I can't figure out how rear shifting was perfectly
fine for the first 30 miles of the ride. All shifts perfect. I'd
think a crooked rear hanger would not shift right.


That's why a crooked derailleur hanger doesn't make sense -- it
doesn't just occur unless you dropped the bike or hit something. An
outside possibility is that you got something into the derailleur
that dragged it into the wheel and bent the hanger, but when that
happens, the derailleur is usually ruined and wound around your
cassettes or in the spokes. My first thought was that your cable was
in the process of failing.


It takes only one rock it, from a rock kicked up by the front tire at
speed. That is why a separate (sacrificial) derailer hanger is a good
thing. They can only be bent back so many times.

--
Regards, Joerg

http://www.analogconsultants.com/
  #17  
Old August 13th 19, 03:47 PM posted to rec.bicycles.tech
Ted Heise
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Posts: 21
Default Bad rear derailleur???

On Sun, 11 Aug 2019 19:09:21 -0700 (PDT),
Chalo wrote:
Note that Shimano road and MTB 10 speed derailleurs have
different pull ratios. Rear derailleurs and shifters are
miscible up to 9 speed.


This might be why I could never get really good shifting on my
tandem, which came with 10-speed Shimano brifters and mountain
bike (XTR?) rear derailer. I could adjust it to shift well across
only part of the cassette. I swapped the rear der for the newish
long throw road derailer, and it now shifts beautifully.

--
Ted Heise West Lafayette, IN, USA
  #18  
Old August 13th 19, 04:15 PM posted to rec.bicycles.tech
Tom Kunich[_5_]
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Posts: 964
Default Bad rear derailleur???

On Tuesday, August 13, 2019 at 7:31:00 AM UTC-7, Joerg wrote:
On 2019-08-11 19:09, Chalo wrote:
Note that Shimano road and MTB 10 speed derailleurs have different
pull ratios. Rear derailleurs and shifters are miscible up to 9
speed.


Not really. I have a 7-speed set-up on my road bike and, after a crash
and restore, wanted to use the Alivio shifters from a 7-speed MTB on my
road bike. Measured the cable pull ration and it was almost 10%
different. So I still have friction shifters on the road bike until I
transplant the derailer. Which won't be easy since I have a 40T cog in back.

--
Regards, Joerg

http://www.analogconsultants.com/


After that car hit me the bike was straightened and it rode fine but would never shift quite right and generally the longer the ride the worse the shifting would get. Finally I eye-balled the rear hanger and it was crooked. Took out the large crescent wrench and straightened it and it shifts perfectly without a hitch.
  #19  
Old August 13th 19, 04:18 PM posted to rec.bicycles.tech
AMuzi
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Posts: 10,787
Default Bad rear derailleur???

On 8/13/2019 9:47 AM, Ted Heise wrote:
On Sun, 11 Aug 2019 19:09:21 -0700 (PDT),
Chalo wrote:
Note that Shimano road and MTB 10 speed derailleurs have
different pull ratios. Rear derailleurs and shifters are
miscible up to 9 speed.


This might be why I could never get really good shifting on my
tandem, which came with 10-speed Shimano brifters and mountain
bike (XTR?) rear derailer. I could adjust it to shift well across
only part of the cassette. I swapped the rear der for the newish
long throw road derailer, and it now shifts beautifully.


Santana builds with Ultegra STi and XTR rears and has for
many years (9, 10, 11 speed format); excellent dependable
setup for wide range gearing:

http://www.yellowjersey.org/sanes19b.html

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


  #20  
Old August 13th 19, 05:19 PM posted to rec.bicycles.tech
Ted Heise
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Posts: 21
Default Bad rear derailleur???

On Tue, 13 Aug 2019 10:18:41 -0500,
AMuzi wrote:
On 8/13/2019 9:47 AM, Ted Heise wrote:
On Sun, 11 Aug 2019 19:09:21 -0700 (PDT),
Chalo wrote:
Note that Shimano road and MTB 10 speed derailleurs have
different pull ratios. Rear derailleurs and shifters are
miscible up to 9 speed.


This might be why I could never get really good shifting on my
tandem, which came with 10-speed Shimano brifters and mountain
bike (XTR?) rear derailer. I could adjust it to shift well
across only part of the cassette. I swapped the rear der for
the newish long throw road derailer, and it now shifts
beautifully.


Santana builds with Ultegra STi and XTR rears and has for many
years (9, 10, 11 speed format); excellent dependable setup for
wide range gearing:

http://www.yellowjersey.org/sanes19b.html


I got my tandem through one of their larger distributors, and it
had a 36-tooth large cog--so it's possible the mountain rear
derailer was not Santana orginal. It's possible that Jack (at
Tandem's Limited) might have built it up himself.

--
Ted Heise West Lafayette, IN, USA
 




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