Shifting problems on shimano 6800 rear derailleur
Hi everyone
I had a pretty wet ride just before I went on a months vacation, and after returning, my rear derailleur won't shift to the smallest cog (highest gear). I also switched wheelset in the meantime, but the problem exist with both old and new wheelset.
I've checked the high-limit screw, and the alignment seems fine. The dropout is not bent. If i manually push the derailleur, I can get it down to the smallest cog. Also, if I step-by-step loosen cable tension on the adjustment screw (or completely unscrew the cable), it easily drops down. Problem solved? Not really - The problem then becomes, that it won't shift into second-smallest cog gear on the first lever pull, and can't switch to the largest cog.
The derailleur seems fine. This leads me to think of the cables or levers (most likely the first?) as the problem. When I adjust the cable tension to allow the derailleur to switch to the smallest cog, almost no cable movement is felt when i try to shift from the smallest cog to the second-smallest, and it stays on the smallest cog.
Since it jumps straight to the smallest cog without cable tension, and the fact that it shifts perfectly from gear 1-10 with more tension (but not to the smallest cog/11th gear), I am assuming that the derailleur is working just fine.
The bike is just 9 months old, and due to a winter injury, it has only done 2.500km. Could the cables really be worn out already?
I had a pretty wet ride just before I went on a months vacation, and after returning, my rear derailleur won't shift to the smallest cog (highest gear). I also switched wheelset in the meantime, but the problem exist with both old and new wheelset.
I've checked the high-limit screw, and the alignment seems fine. The dropout is not bent. If i manually push the derailleur, I can get it down to the smallest cog. Also, if I step-by-step loosen cable tension on the adjustment screw (or completely unscrew the cable), it easily drops down. Problem solved? Not really - The problem then becomes, that it won't shift into second-smallest cog gear on the first lever pull, and can't switch to the largest cog.
The derailleur seems fine. This leads me to think of the cables or levers (most likely the first?) as the problem. When I adjust the cable tension to allow the derailleur to switch to the smallest cog, almost no cable movement is felt when i try to shift from the smallest cog to the second-smallest, and it stays on the smallest cog.
Since it jumps straight to the smallest cog without cable tension, and the fact that it shifts perfectly from gear 1-10 with more tension (but not to the smallest cog/11th gear), I am assuming that the derailleur is working just fine.
The bike is just 9 months old, and due to a winter injury, it has only done 2.500km. Could the cables really be worn out already?
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Comments
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Not necessarily "worn out" but perhaps some corrosion/dirt inside the outer. I'd suggest replacing both inner and outer and see what happens.0
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Yeah - sounds like classic cable inner/outer sticking issue.
The kicker is that you left the bike for 4 weeks unused after a wet ride. My guess is that there is some corrosion or possibly a build up of crud somewhere along the length of your rear derailleur cable run.
If you feel confident enough to do it, I would disconnect the inner cable at the derailleur, pull back the hood on the rear shifter and dislodge the inner cable so that you can pull it out of the shifter body (it may take a bit of piggling and possible removing the small side plate on the shifter body to achieve this).
Don't pull it all the way - maybe 25cm or so. Apply cleaner/ lubricant to the inner cable and pull it back and forward to work the cleaner/lubricant through as much of the outer as possible. After that try refitting the cable at the derailleur end and start your indexing set up as per this video
https://www.youtube.com/watch?v=SkzvfCaIbyQ0 -
The rear cable outer is a good thing to check it's frequently a cause of this issue, but there is also another more subtle possibility. I know this because I've had exactly the same issue on the 6800 rear mech on my bike, and seen it on one or two others.
Where the inner cable exits the derailleur on its way to the clamp it runs through a narrow plastic sleeve. This I think is a design compromise to protect the inner cable from being abraded by the metal body of the mech, as it gets pulled at some pretty extreme angles. I fully expect a future design revision to that part in future.
What happens is that this plastic sleeve can get cut up and rough, causing the inner cable to bind on it or the mech body. If you're confident about releasing the cable you can push this inner sleeve out by holding it and pushing it up towards the adjuster barrel. It's a subcomponent of the cable ferrule that runs inside the adjuster barrel. Check it for damage, and if it shows any holes or tears get a new one. Most LBS will have them lying around.0 -
Thank you for the input guys.
A quick update. I went riding with 10 gears today, and the source of the problem suddenly revealed itself, when the shifting completely gave out.
Below is a picture of the cable from inside the lever, including the plastic tongue. The small part was a bit of a pain to get out. Don't know how the f*** it ended up like this :?
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Thank you for the input guys.
A quick update. I went riding with 10 gears today, and the source of the problem suddenly revealed itself, when the shifting completely gave out.
Below is a picture of the cable from inside the lever, including the plastic tongue. The small part was a bit of a pain to get out. Don't know how the f*** it ended up like this :?
That would have been the next suggestion - it's a fairly common (and bloody annoying) failure.0 -
For starters, that is not a Shimano low friction cable.
But the reason it broke could be in the way it was fitted.
Some people push the cable though the shifter and then twist it in a loop to feed it back into the casing under the bar tape.
This creates a loop that gets tighter and tighter until it snaps into position, kinking the cable slightly as it does so. This sets the cable up for failure at that point.
If you do the loop thing to fed it at the very end of the cable the kink happens in a bit of the cable that gets cut off, but if you pull the whole cable through the shifter and then feed it into the casing creating the loop, the kink happens exactly where yours broke.
Being that it is not an original cable, my bet is that the correct casing end with the guide slot and extended tongue has also not been used, again causing problems.
Fit a new Shimano cable, correct casing end, and use the Shimano cable grease on it and I bet it won't fail and will amaze you with how light and positive it is.
There have been a few Dura-ace cable failures at that point in the cable as well and there was an early revision to the shifter, but I have not heard of this problem in the Ultegra series yet.0 -
This exact same thing happened to me around 6 weeks ago on a factory fitted cable, seems to be a known problem on the Dura Ace shifters as well.0
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Resurrecting this old thread as I am having what I think may be the same problem. The photo linked above is no longer accessible so I do not know what to check for.
All of a sudden my 6800 rear derailleur only works on 8 gears. Altering the cable tension I can change that to either the top 8 or the bottom 8 gears, but appear to have lost the full range. Shifting between the 8 gears that I can access is absolutely fine.
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I'd whip the cable out as soon as you can. Release the clamp bolt on the RD and free the cable. You should then be able to push it back out of the shifter. If you leave it till it breaks there's an increased chance of stray wires becoming lodged in the internals.
Shimano tech docs will have the dealer and user manuals for the shifter if you need them, or Youtube.0 -
Thanks, will give that a go.keef66 wrote:I'd whip the cable out as soon as you can. Release the clamp bolt on the RD and free the cable. You should then be able to push it back out of the shifter. If you leave it till it breaks there's an increased chance of stray wires becoming lodged in the internals.
Shimano tech docs will have the dealer and user manuals for the shifter if you need them, or Youtube.0
