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What is wrong with this rear derailleur?

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What is wrong with this rear derailleur?

Old 12-13-21, 03:57 PM
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Jicafold
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What is wrong with this rear derailleur?

Not my bike. Just a picture. I think either this derailleur body is stuck in the wrong position or the chain is too short. It is already on the smalIest sprocket and chainring. I don't see any way possible it could shift to the large chain ring or a larger sprocket and have any chain left. Your opinions?

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Old 12-13-21, 04:19 PM
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Originally Posted by Jicafold View Post
Not my bike. Just a picture. I think either this derailleur body is stuck in the wrong position or the chain is too short. It is already on the smalIest sprocket and chainring. I don't see any way possible it could shift to the large chain ring or a larger sprocket and have any chain left. Your opinions?

The claw looks to be attached in the wrong place. It looks like they have attached to the fender mount when it should be clamped to the dropout. It looks like itís positioned like this and has rotated upwards some. Itís essentially an extreme B screw adjustment.




Itís should look like this. There is a stop that should go in the dropout that holds the claw in the proper place.

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Old 12-13-21, 05:39 PM
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Originally Posted by cyccommute View Post
The claw looks to be attached in the wrong place. It looks like they have attached to the fender mount when it should be clamped to the dropout. It looks like itís positioned like this and has rotated upwards some. Itís essentially an extreme B screw adjustment.

Itís should look like this. There is a stop that should go in the dropout that holds the claw in the proper place.
I should have posted this photo also. Looks like the mounting claw is in the right spot.

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Old 12-13-21, 06:00 PM
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Main pivot is stuck? Could be corrosion in the pivot that's keeping it from swinging as it should.
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Old 12-13-21, 07:01 PM
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I don't think the chain is routed correctly....but hard to see for sure
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Old 12-13-21, 08:53 PM
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These double pivot sprung ders will "hang at an angle" that reflects the two spring strengths, assuming both pivots are freely rotating. Too short a chain will see the cage played out and the parallelogram rotated forward. The photo shows a cage partially played out but the parallelogram rotated back. This can happen when, as cxwrench said, the cage pivot is sticky or hindered in its rotational movement. When removing and reinstalling a rear wheel, like shown, the der usually get's pulled back. If the cage pivot is tight on reinstall that pivot doesn't move and the B pivot tries to take up the chain droop. Andy
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Old 12-13-21, 09:00 PM
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Jicafold's right. The spring or bolt that attaches the unit to the claw is messed up. The pantograph should point forward and down at about 15į, not straight down. Also shown in this manual for the Shimano Z501 (which is what your bike may have)
https://manualzz.com/doc/53871114/sh...e-instructions


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Old 12-14-21, 02:21 PM
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Jicafold, have you tried moving the derailleur forward and backward by hand? That should tell you if the upper pivot is gummed up. It's happened to me.

RJ video on the subject:
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Old 12-14-21, 05:36 PM
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Originally Posted by Andrew R Stewart View Post
These double pivot sprung ders will "hang at an angle" that reflects the two spring strengths, assuming both pivots are freely rotating. Too short a chain will see the cage played out and the parallelogram rotated forward. The photo shows a cage partially played out but the parallelogram rotated back. This can happen when, as cxwrench said, the cage pivot is sticky or hindered in its rotational movement. When removing and reinstalling a rear wheel, like shown, the der usually get's pulled back. If the cage pivot is tight on reinstall that pivot doesn't move and the B pivot tries to take up the chain droop. Andy
I am editing an earlier reply because I see you weighed in here. You are correct, as usual. However, I see much more potential ... angle in the jockey pulleys as shown. Right now they are in about a vertical orientation. The wrap cage is about six o'clock instead of the four or five o'clock that is possible at max capacity. I don't get the sense from the o.p. that s/he has actually tried to shift to the big ring to see what would happen. They should do so and report back. Those cranksets had only about 10 teeth of difference between small and big ring. I think that is there more than enough (un)wrap left for the big-little and more. I wouldn't lay any bets on a big-big, but certainly up to the middle of the cluster is possible. The o.p. should be on the small ring for much bigger than ~ third cog from the big end of the cluster anyway.
Edit:Never mind, I see the problem. And that IS the problem. All we can do is SEE the problem. What this needs is someone who can 'touch' the problem. If I could actually get up close and personal to that thing I could set it right. So ... o.p. if you can't actually get joy through unsdoing the main connection of the derailleur body to the hanger then you need to take the bike over to a co-op where a tech will have you out the door in a few minutes.

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Old 12-15-21, 01:57 AM
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It's not the OP's bike, so....

IF there's a backing nut for the claw/pivot bolt interface, it may be too tight...or there's no bushing to allow the derailleur to pivot
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Old 12-15-21, 07:02 AM
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Always like the RJ the bike guy videos !!!

He has helped me with a few things

Good Luck with the RD !
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Old 12-16-21, 02:04 PM
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It’s not my bike. A local seller on Craigslist. I tried to explain to him that it wasn’t right and there is no way it could function properly. Suggested he take it to a shop. Of course he denies that and says it shifts perfectly. Which can’t possibly be true. You can lead a horse to water… But you can’t make them drink.

https://sanantonio.craigslist.org/bi...420056101.html

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Old 12-16-21, 06:14 PM
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Originally Posted by Jicafold View Post
Itís not my bike. A local seller on Craigslist. I tried to explain to him that it wasnít right and there is no way it could function properly. Suggested he take it to a shop. Of course he denies that and says it shifts perfectly. Which canít possibly be true. You can lead a horse to waterÖ But you canít make them drink.

https://sanantonio.craigslist.org/bi...420056101.html
Unless you want the bike and can lowball it, I wouldn't pound my head against the wall with a seller like this.... they don't appreciate any input
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