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Shimano Dura Ace rear der. sticking up and down
Last Post 06/05/2013 10:26 PM by Andy Eunson. 13 Replies.
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eurochien

Posts:40

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05/31/2013 12:41 AM

I'm having a shifting problem that is starting to get on my nerves. My Tri bike (Argon 18 E-114) has 10-sp. indexed Dura Ace bar end shifters. The rear derailleur is Dura Ace 10 sp. as well. I think the gruppo is from 2007.
Anyway, the range screws are set, and there's good tension on the cable when the chain is in the smallest cog. But shifting up or down at cog 4 or 5, the derailleur just stays there and I have to double shift to move to the next cog (and shift back one gear). It's driving me insane. I had the bike on the stand last night and noticed that the derailleur doesn't even move when I shift up or down when I'm in those middle cogs. Moving the barrel adjuster one way or the other only helps for either direction, it doesn't balance out, which means that when I have trouble shifting down, I turn the barrel adjuster until the shift down takes place and turn it back 1/4 turn, but if I want to shift up from there it won't happen until I turn the barrel adjuster past the original point. In other words those middle gears are completely screwed up. I've never had something quite like this before (I'm a Campy guy) in all my bikes. Could it be that the rear derailleur spring is worn or something? I replaced the cables last year (it was quite a doozy with the internal cable routing). The bike shifted OK last year (it was never great but nothing like this year), I've put maybe 600 miles on the bike between last year and now. Any sensible tip is appreciated.

79pmooney

Posts:1097

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05/31/2013 02:28 AM
My first guess - a cable or housing issue, especially the cable. Sounds like it could be a broken strand which hangs up until you've pulled it clear past the start of that portion of housing. Try a new one. Since shifting wasn't swell after the last change, go new housings as well. Also look to see if there are any snags on the frame, lever and derailleur that could be shortening the life of your cable.

Ben
CB2

Posts:18

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05/31/2013 07:12 AM
Bent derailleur hanger
Keith Richards

Posts:727

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05/31/2013 10:20 AM
What CB2 said first, what 79pmooney said second. What I would normally do on such occasions is remove the cable from the derailleur pinch bolt and hold it in your hand tight while you go through all the gears on your shifters. All the clicks should feel the same. If they don't, the problem is in your cables/housings/shifter and not in your derailleur or its alignment.
----- It is his word versus ours. We like our word. We like where we stand and we like our credibility."--Lance Armstrong.
eurochien

Posts:40

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06/02/2013 10:14 PM
Nah, that's not it. The derailleur hanger is straight and aligned and the cable is clean, no frayed strands. I think it might either be the rear derailleur spring or the shifter indexing is damaged. It's like the shifting gets lazy when it gets in those middle gears. 4 hours dealing with this Dura Ace lousy shifting (two shifts to get one and then back shift) makes me consider changing the gruppo to Campy Chorus.
CERV

Posts:151

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06/03/2013 12:06 AM
maybe a simple question, but are you sure you're not one gear off in your indexing? the first click of the shifter moves up one gear, and not the 2nd click?

try wd-40 soaking the shifter
put the straw in the gap at the top of the lever, a rag under it and soak it.
CERV

Posts:151

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06/03/2013 12:15 AM
also,
is the b-tension correct?

are the pulley bushings worn (play in the pulley?)
Oldfart

Posts:462

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06/03/2013 02:09 AM
Another thing to check is the b pivot. I used to have to service that pivot on the mountain bike annually. If it sticks, the top pulley wheel is too far from the cogs and shifting suffers.
Master50

Posts:226

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06/03/2013 10:05 AM
I don't know how the DA bar end shifters work but if the internal mechanism is like their grifters try cleaning them out with WD-40. and run the shifters up and down the cassette without the wheel in. Also verify the rear der. moves up and down smoothly by pushing the der across the range to feel the motion of the der is smooth and free of any notch.
Cables and housing are cheap enough that changing them every 2 or 3 years is good and a TT bike might sit far too long between exercises?
I am a great Campy fan but replacing the drivetrain should be a lot too far to go. I mean worst case the DA system might need a new bar end shifter but is more likely just gummed up and dirty. I just can't imagine it is the set as most DA parts are good for 10s of thousands of Kilometres. My wife's winter bike still has 1989 DA shifters with a newer 9 speed rear mech. Even the old der was still good enough for a winter bike but it was getting wiggly. The only major service was a soaking of the brifters in kerosene 10 years ago
CB2

Posts:18

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06/04/2013 06:02 AM
Are the two "sticky cogs" the ones you use most? We've seen cassettes that shifted fine in all but the cogs that the rider had worn out.
C2K_Rider

Posts:168

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06/04/2013 12:34 PM
I had similar problems a couple time for different reasons. 1) one timeI found the bottom bracket guide was gunked up with road tar from a recent chip-seal job and the cable was kind of glued in place. cleaning that solved it. 2) on a new bike with internal routing I found I had to forgo a n inline adjuster and use teflon-coated cables to obtain reliable shifting. The cables had a bit too much friction so the der was slow or needed a double shift.
Gonzo Cyclist

Posts:201

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06/05/2013 03:16 AM
something could be gummed up as suggested, check your pulley wheels also, we have found that the DA cables are a hair thinner also, we had to remove a little inline shifter window once, it was causing a delay in the shifting
eurochien

Posts:40

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06/05/2013 10:21 PM
First off, thanks everyone for your suggestions. As it turns out, I put on a new chain, and kazaam, that fixed the problem. I'm as baffled as I've ever been, because I did not expect any dramatic changes in the shifting. I just happened to lose a connecting link that the previous owner had put on the Dura Ace chain and I ended up having to buy a new chain, which did the trick, to my surprise.
Oldfart

Posts:462

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06/05/2013 10:26 PM
Chains do get laterally flexible as they age. They don't shift so well when that happens.
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