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Discussion Starter · #1 ·
Hi,

I have following funny problem that I can not rid of.

I have 9-sp drivetrain (105 shifters, otherwise Ultegra), and last few days it exposes funny behavior:
shifting is quite ok (front and rear) but if I try to turn cranks backwards chain strat to fold up under the rear end of the from derailer - even if I turn cranks only 1/2 turn (e.g. to bring pedal up). I began some days ago without any apparent reason.

Any suggestions?
 

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Larry Lackapants
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al0 said:
Hi,

I have following funny problem that I can not rid of.

I have 9-sp drivetrain (105 shifters, otherwise Ultegra), and last few days it exposes funny behavior:
shifting is quite ok (front and rear) but if I try to turn cranks backwards chain strat to fold up under the rear end of the from derailer - even if I turn cranks only 1/2 turn (e.g. to bring pedal up). I began some days ago without any apparent reason.

Any suggestions?
1 - derailler cable slipped a bit up front.
2 - front derailler is not parallel to the chainwheels any more.

fix:
- loosen cable, loosen derailler bolt, make sure the der's outer plate is parallel to the large ring, and about 2 mm far from the ring's teeth
- tighten derailler bolt, then fasten cable and adjust until front shifts from small to large are not thrown over the large ring any more.
in short..
good luck
brblue
 

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hello
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Has nothing to do with the front derailleur.
It could be a number of thing in the rear end of the bike that's causing this binding......(sticky hub, RD pulley, etc...)
 

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Discussion Starter · #4 ·
brblue said:
1 - derailler cable slipped a bit up front.
That's possible, but it should cause some detioration of a shifting performance - which is not a case, moreover, derailer has a (very slight) tendecy to overshift, which is not likely with cable slack. Am I wrong?

brblue said:
2 - front derailler is not parallel to the chainwheels any more.
Not the case, I have cheked it before my first post.
 

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Discussion Starter · #5 ·
roadfix said:
Has nothing to do with the front derailleur.
This why I has put a question mark in the subject line.
roadfix said:
It could be a number of thing in the rear end of the bike that's causing this binding......(sticky hub, RD pulley, etc...)
Pulleys was replaced circa 2 months ago, not likely to be problem.

Hub, yes, that may be a cause - freewheel body was replaced a week ago with a brand-new one (old stopped to engage - in the middle of the ride, BTW). It may be somewhat sticky so - it has only about 150 miles in it. I'm only somewhat perpexed -why the problem strted not immediately after freewhell body change, but after 50-60 miles? First couple of rides all were running absolutely smoothly.

And if problem is casued by hund, how to fix it? (Ultegra 6600).
 

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hello
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Does this happen when the chain tension is slack?....ie, small chainring/smallish cog combo? If so, also check to see if the chain is not too long.
 

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Discussion Starter · #7 ·
roadfix said:
Does this happen when the chain tension is slack?....ie, small chainring/smallish cog combo? If so, also check to see if the chain is not too long.
No it happens on ring and cogs combos. On big ring it is even more prominent.
 

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Chain suck

al0 said:
if I try to turn cranks backwards chain strat to fold up under the rear end of the from derailer - even if I turn cranks only 1/2 turn (e.g. to bring pedal up). I began some days ago without any apparent reason.

Any suggestions?
It sounds like the chain is "sticking" to the chainring, and these are the reasons that might happen: it could be a stiff link in the chain, a worn or poorly lubricated chain, or a worn chainring.
 

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Discussion Starter · #9 ·
Kerry Irons said:
It sounds like the chain is "sticking" to the chainring, and these are the reasons that might happen: it could be a stiff link in the chain, a worn or poorly lubricated chain, or a worn chainring.
Chain is good lubricated (and lubrication does not provide any difference) and not extremely worn (~600 miles).

Stiff link - would check at evening, definitely possible.

Warn chainring - as well possible (~8000 miles), but problem occurs on both chainrings and small one I use quite rarely, so it should not be worn a lot.

Tnanks.
 

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hello
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Lift the bike and turn the rear wheel forward. If the hub is not ratcheting and turning the cranks, there might be excessive friction in the hub.
 

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Discussion Starter · #11 ·
roadfix said:
Lift the bike and turn the rear wheel forward. If the hub is not ratcheting and turning the cranks, there might be excessive friction in the hub.
Seems not to be a case - wheel moves absolutely freely, cranks are still.
 

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Discussion Starter · #12 ·
Kerry Irons said:
It sounds like the chain is "sticking" to the chainring, and these are the reasons that might happen: it could be a stiff link in the chain, a worn or poorly lubricated chain, or a worn chainring.
At first glance no stiff link exists. Tomorrow I would remove a chain and inspect it carefully link by link.

Chainrings do not look heavile worn as well (from teeth profile).

BTW, after some tweaking behavior has somewhat changed - chain does not fold up, but rather starts to fold up then straighten, so when I turn cranks backwards it makes "clack-clack-clack".
 

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Well, since you've eliminated most of the other suspects, I'm going to guess rear derailleur pulley. I know my Ultegra 9-speed upper pulley is pretty stiff.
 

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Discussion Starter · #14 ·
russotto said:
Well, since you've eliminated most of the other suspects, I'm going to guess rear derailleur pulley. I know my Ultegra 9-speed upper pulley is pretty stiff.
Thanks, would check.
 

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I have a Scott CX1 Pro all stock. I want to upgrade the Ultegra front derailer, possibly with an Ultegra SL. Is this much of an improvement and will the SL work without any other changes? Any other suggestions for an upgrade?
 

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Discussion Starter · #16 ·
The most likely it would be next-to-nothing upgrade.
As for suggestions - what goal you want to reach with an upgrade?
TwoTiredRider said:
I have a Scott CX1 Pro all stock. I want to upgrade the Ultegra front derailer, possibly with an Ultegra SL. Is this much of an improvement and will the SL work without any other changes? Any other suggestions for an upgrade?
 
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