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-   -   Dura Ace RD-7700 bar end (https://www.bikeforums.net/bicycle-mechanics/1227171-dura-ace-rd-7700-bar-end.html)

danders 03-31-21 07:33 AM

Dura Ace RD-7700 bar end
 
Doesn't index correctly, I get some double shifts. Can it be fixed or rebuilt?
Friction works fine.
Using 9 spd 11-34 cassette and Acera RD incase I have overlooked compatibility issues.

Andrew R Stewart 03-31-21 07:38 AM

Is the problem that the lever has more "free movement", when it's in the index mode, as it settles back into the detent? Or put another way does the lever have a greater amount of movement before it changes the denent it's in? If so then this is a well known issue of some older units. I have replaced a few due to this.

Of course one should do all the usual confirmations of cable friction (minimal), cable tension (actually casing length) and der alignment first. This hasn't been said and I won't assume that these steps have been done. Andy

oldbobcat 03-31-21 08:29 AM

Loss of indexing is almost always caused by the derailleur taking a whack and knocking the hanger out of alignment. If you don't have the alignment tool, take your bike to a shop and have the hanger checked and aligned. They will detach the derailleur, tweak the hanger, reattach the derailleur, and adjust, usually for less than 30 bucks.

danders 03-31-21 08:51 AM


Originally Posted by Andrew R Stewart (Post 21993341)
Is the problem that the lever has more "free movement", when it's in the index mode, as it settles back into the detent? Or put another way does the lever have a greater amount of movement before it changes the denent it's in? If so then this is a well known issue of some older units. I have replaced a few due to this.

Of course one should do all the usual confirmations of cable friction (minimal), cable tension (actually casing length) and der alignment first. This hasn't been said and I won't assume that these steps have been done. Andy

Yes it seems to skip a detent and double shift, and lever seems to have greater movement on double shifts.
It lines up fine on the gears it selects. New setup so no bent hangers etc. Lower gearing for the Vaya.
Sounds like Shimano intends these to be non serviceable? Nice business model.

dsbrantjr 03-31-21 09:44 AM


Originally Posted by danders (Post 21993501)
Yes it seems to skip a detent and double shift, and lever seems to have greater movement on double shifts.
It lines up fine on the gears it selects. New setup so no bent hangers etc. Lower gearing for the Vaya.
Sounds like Shimano intends these to be non serviceable? Nice business model.

New setup ≠ hanger alignment not needed.

Andrew R Stewart 03-31-21 07:42 PM


Originally Posted by danders (Post 21993501)
Yes it seems to skip a detent and double shift, and lever seems to have greater movement on double shifts.
It lines up fine on the gears it selects. New setup so no bent hangers etc. Lower gearing for the Vaya.
Sounds like Shimano intends these to be non serviceable? Nice business model.

Welcome to the future of things. The bike industry has been tipping toward this model for decades. IMO the biggie motivation is us, the consumer. We eat up "newest and bestest" stuff and discount the value of last year's bestest. After a few years the LBS segment learned to stop buying the small internal wear prone parts in many cases. The factories reduced their production of too slow moving repair parts. It's a cycle with no real beginning or end point but it feeds on it's self just the same.

What to do about it? Stop buying the latest stuff. Sure... Andy

Edward1066 03-31-21 08:05 PM

Check to make sure the chrome plastic bushing is installed correctly. After a handlebar swap once, mine would index 123, go friction 456, and then index the last three. Correct orientation of that bushing is key.

danders 04-01-21 06:40 AM


Originally Posted by Edward1066 (Post 21994744)
Check to make sure the chrome plastic bushing is installed correctly. After a handlebar swap once, mine would index 123, go friction 456, and then index the last three. Correct orientation of that bushing is key.

Thanks I will look into this over the weekend, seems like a likely possibility.
It's the washer/bushings in the center of image?
https://cimg8.ibsrv.net/gimg/bikefor...fbfc8c3ebc.png

Edward1066 04-01-21 03:14 PM


Originally Posted by danders (Post 21995126)
Thanks I will look into this over the weekend, seems like a likely possibility.
It's the washer/bushings in the center of image?
https://cimg8.ibsrv.net/gimg/bikefor...fbfc8c3ebc.png

It's the plastic bushing still attached to the shifter body I was speaking about. It has 4 possible orientations, but, only one correct.


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