Shimano Rear Derailleur Indexing Problem

[Giga Watts]

Hello gurus!

I am having a problem with the shifting of my Shimano Deore 9-speed
rear derailleur. If I have been shifting up, and then need to shift
down one cog, I need to shift down twice (or, two index clicks, so to
speak) to go to the proper cog. Likewise, if I've been shifting down,
and need to shift up, I have to shift up (two clicks) twice to get to
the desired cog.

I've attempted to clean, oil, and adjust the derailleur according to
Barnett's Manual. Also, FWIW, the shifters are stock, and I've cleaned
and lubed the inner wire. The Guide and Tension pulleys look to be in
good condition, but I suspect the problem may lie with them...

I am seeing about 1 mm of axial play on the Guide Pulley (labelled
Shimano Centeron G-Pulley). The tension pulley has no more than 1/2 mm
axial play (labelled Shimano Narrow). My theory is that when I shift,
the guide pulley is simply sliding over rather than forcing the chain
over to the next cog.

Is that much axial play standard for these pulleys and do I need to
look elsewhere for my problem? Or should I replace the G-Pulley? Not
that a pulley is big bucks, I just don't like fixing things that aren't
broken!

Thanks for any assistance,

GW

 

[[email protected]]

GW:

Not a "guru" per se, but I do have one comment and that is that the
ramps carved into the cogs in the back have more to do with indexed
shifting than the tiny bit of play in your pulleys.

I would suggest looking to your shifters for the failure.

App

 

[Zog The Undeniable]

Giga Watts wrote:

> Hello gurus!
>
> I am having a problem with the shifting of my Shimano Deore 9-speed
> rear derailleur. If I have been shifting up, and then need to shift
> down one cog, I need to shift down twice (or, two index clicks, so to
> speak) to go to the proper cog. Likewise, if I've been shifting down,
> and need to shift up, I have to shift up (two clicks) twice to get to
> the desired cog.
>
> I've attempted to clean, oil, and adjust the derailleur according to
> Barnett's Manual. Also, FWIW, the shifters are stock, and I've cleaned
> and lubed the inner wire. The Guide and Tension pulleys look to be in
> good condition, but I suspect the problem may lie with them...
>
> I am seeing about 1 mm of axial play on the Guide Pulley (labelled
> Shimano Centeron G-Pulley). The tension pulley has no more than 1/2 mm
> axial play (labelled Shimano Narrow). My theory is that when I shift,
> the guide pulley is simply sliding over rather than forcing the chain
> over to the next cog.

That is both normal and essential to the functioning of the system.
Note that the pulley should slide axially; it shouldn't rock out of plane.

Could the shifters be worn out?

 

[Monk]

Could a "stretched" chain cause this?

 

[Werehatrack]

On 26 Apr 2005 11:06:29 -0700, "Giga Watts" <[email protected]>
wrote:

>Hello gurus!
>
>I am having a problem with the shifting of my Shimano Deore 9-speed
>rear derailleur. If I have been shifting up, and then need to shift
>down one cog, I need to shift down twice (or, two index clicks, so to
>speak) to go to the proper cog. Likewise, if I've been shifting down,
>and need to shift up, I have to shift up (two clicks) twice to get to
>the desired cog.

Is this a new problem on a bike you've had for a while, or a problem
that came with the bike?

This sounds exactly like the symptoms I had in a bike whose prior
owner had rigged the shifters using cheap brake cable housing. If the
cable housing is obviously made from a tight-spiral wire, I'd swap out
the housing for some axial-wire der cable housing before trying
anything else.

If this problem developed over time in a system that otherwise was
working correctly, I'd look at the shifters first; crud in the
mechanism or inadequate lube can have the described effects.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Werehatrack]

On 26 Apr 2005 14:49:28 -0700, "Monk" <[email protected]> wrote:

>Could a "stretched" chain cause this?

No.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Vee]

Giga Watts wrote:

> (snip slow shifting problems)

Measure your chain for wear first
(http://www.sheldonbrown.com/chains.html). If it's okay, and you're
sure your cassette is also okay, check your derailleur hanger
alignment. Might need a bike shop to help you. Replacing your shift
cable and housing might be required, too, but if it's slow in both
directions, my guess is wear and/or bent hanger.

-Vee

 

[Giga Watts]

Werehatrack wrote:
> On 26 Apr 2005 11:06:29 -0700, "Giga Watts" <[email protected]>
> wrote:
>
> >Hello gurus!
> >
> >I am having a problem with the shifting of my Shimano Deore 9-speed
> >rear derailleur. If I have been shifting up, and then need to shift
> >down one cog, I need to shift down twice (or, two index clicks, so
to
> >speak) to go to the proper cog. Likewise, if I've been shifting
down,
> >and need to shift up, I have to shift up (two clicks) twice to get
to
> >the desired cog.
>
> Is this a new problem on a bike you've had for a while, or a problem
> that came with the bike?

I bought the bike new, and it's now got about 4K Miles on it, all with
original equipment (well, not the tires!) and it's been gradually doing
this. I did have a problem with the rear derailleur inner wire when it
broke last season, so I replaced it (but not the housing). The rear
loop IS probably a bit short...


>
> This sounds exactly like the symptoms I had in a bike whose prior
> owner had rigged the shifters using cheap brake cable housing. If
the
> cable housing is obviously made from a tight-spiral wire, I'd swap
out
> the housing for some axial-wire der cable housing before trying
> anything else.
>
> If this problem developed over time in a system that otherwise was
> working correctly, I'd look at the shifters first; crud in the
> mechanism or inadequate lube can have the described effects.

When I replaced the inner wire, I had to clean out the shifter. I will
take a look at it again. I'll see if I can find an assembly diagram so
I can take the darn thing apart (and get it back together) to do the
job right.

> --
> Typoes are a feature, not a bug.
> Some gardening required to reply via email.
> Words processed in a facility that contains nuts.

Thanks for the ideas!

GW

 

[Giga Watts]

Zog The Undeniable wrote:

<Original post Snipped>
>
> That is both normal and essential to the functioning of the system.
> Note that the pulley should slide axially; it shouldn't rock out of
plane.

Yeah, I found another Deore derailleur (a few years newer, but
whatever) and its g-pulley also moves axially by about the same amount,
so that isn't it! The pulley is in pretty good shape, with no radial
play, but the axial play (especially compared with the T-pulley) fooled
me.

>
> Could the shifters be worn out?

A couple of people mentioned the problem could be with the shifter, so
I am going to dig in and see what kind of **** I have in there... I
did replace the inner wire last season when it went "twang" on a ride,
so I may have missed some bits...

Thanks!

GW

 

[Vee]

Giga Watts wrote:

> I bought the bike new, and it's now got about 4K Miles on it

Chain and cassette wear is probably part of your problem. Measure your
chain before doing anything else.

> When I replaced the inner wire, I had to clean out the shifter.

Overhauling the shifter is premature and probably a waste of time.
They almost never act up in this way. Your description of slow
shifting in both directions cries out "worn drivetrain" and/or "bent
derailleur hanger" and/or "crappy shift housing".

-Vee

 

[Peter Cole]

"Giga Watts" <[email protected]> wrote in message
>
> I bought the bike new, and it's now got about 4K Miles on it, all with
> original equipment (well, not the tires!) and it's been gradually doing
> this. I did have a problem with the rear derailleur inner wire when it
> broke last season, so I replaced it (but not the housing). The rear
> loop IS probably a bit short...

In my experience, the cause of sluggish shifting is usually
dirty/worn/broken housing, especially the last loop. Check that housing
hasn't cracked anywhere, and that ends are square and fit well to ferrules.
You don't want the housing to compress/flex anywhere. Make sure you've
fastened the cable end properly, too. 4K miles shouldn't wear out shifter
or derailer, suspect the obvious culprits first.

 

[Marvin]

Werehatrack wrote:
> On 26 Apr 2005 14:49:28 -0700, "Monk" <[email protected]> wrote:
>
> >Could a "stretched" chain cause this?
>
> No.

Yes. Or rather, a worn chain can cause crappy shifting, because it
loses lateral stiffness and bends instead of being derailled. It still
sounds like a good clean and/or replacement of the gear cable is the
solution, but chain wear would be next on my list.

 

[Giga Watts]

Vee wrote:
> Giga Watts wrote:
>
> > I bought the bike new, and it's now got about 4K Miles on it
>
> Chain and cassette wear is probably part of your problem. Measure
your
> chain before doing anything else.
>
> > When I replaced the inner wire, I had to clean out the shifter.
>
> Overhauling the shifter is premature and probably a waste of time.
> They almost never act up in this way. Your description of slow
> shifting in both directions cries out "worn drivetrain" and/or "bent
> derailleur hanger" and/or "crappy shift housing".
>
> -Vee

Vee (and all):

I checked a number of things. Thanks for all the suggestions. They
certainly pointed me in the right direction.

The chain is indeed worn -- I measured a 12" section and the 12" pin
was 3/32" over. Time to replace the chain (and find a better way of
cleaning and lubing the thing...).

The hanger was a bit bent (probably a deflection of 1/32"). I
straightened it as best I could (Hmmm, I musta misplaced my hanger
alignment tool and now I'm getting significantly better shifts. It
shifts down almost perfectly, but when upshifting I have to give the
shifter a tiny nudge past the index to make it go, which I can live
with in the short term.

And I'm convinced that the rear loop is too short and probably worn
out. I'm gonna replace that housing and probably the inner wire, too.

I'm gonna wait on overhauling the shifter until I get these obvious
(well, NOW they're obvious!) problems fixed.

Sigh. Time waits for no man (or his bike).

Thanks again!

GW

 

[[email protected]]

Giga Watts wrote:
> Hello gurus!
>
> I am having a problem with the shifting of my Shimano Deore 9-speed
> rear derailleur. If I have been shifting up, and then need to shift
> down one cog, I need to shift down twice (or, two index clicks, so to
> speak) to go to the proper cog. Likewise, if I've been shifting
down,
> and need to shift up, I have to shift up (two clicks) twice to get to
> the desired cog.
>
> I've attempted to clean, oil, and adjust the derailleur according to
> Barnett's Manual. Also, FWIW, the shifters are stock, and I've
cleaned
> and lubed the inner wire. The Guide and Tension pulleys look to be
in
> good condition, but I suspect the problem may lie with them...
>
> I am seeing about 1 mm of axial play on the Guide Pulley (labelled
> Shimano Centeron G-Pulley). The tension pulley has no more than 1/2
mm
> axial play (labelled Shimano Narrow). My theory is that when I
shift,
> the guide pulley is simply sliding over rather than forcing the chain
> over to the next cog.
>
> Is that much axial play standard for these pulleys and do I need to
> look elsewhere for my problem? Or should I replace the G-Pulley?
Not
> that a pulley is big bucks, I just don't like fixing things that
aren't
> broken!
>
> Thanks for any assistance,
>
> GW

Also try adjust the "B" screw on the rear derailleur (the one that
screws up against the tab on the dropout derailleur hanger) so that the
jockey pulley is as close to the cogs as possible without rattling
against them, in all gear combinations.

Also use the narrowest (1.1mm) non-teflon coated cable.


Dan Christopherson
Lopez Island WA

 

[[email protected]]

non teflon-coated cable.

 

[Bill Lloyd]

On 2005-04-26 11:06:29 -0700, "Giga Watts" <[email protected]> said:

> Hello gurus!
>
> I am having a problem with the shifting of my Shimano Deore 9-speed
> rear derailleur. If I have been shifting up, and then need to shift
> down one cog, I need to shift down twice (or, two index clicks, so to
> speak) to go to the proper cog. Likewise, if I've been shifting down,
> and need to shift up, I have to shift up (two clicks) twice to get to
> the desired cog.
>
> I've attempted to clean, oil, and adjust the derailleur according to
> Barnett's Manual. Also, FWIW, the shifters are stock, and I've cleaned
> and lubed the inner wire. The Guide and Tension pulleys look to be in
> good condition, but I suspect the problem may lie with them...
>
> I am seeing about 1 mm of axial play on the Guide Pulley (labelled
> Shimano Centeron G-Pulley). The tension pulley has no more than 1/2 mm
> axial play (labelled Shimano Narrow). My theory is that when I shift,
> the guide pulley is simply sliding over rather than forcing the chain
> over to the next cog.
>
> Is that much axial play standard for these pulleys and do I need to
> look elsewhere for my problem? Or should I replace the G-Pulley? Not
> that a pulley is big bucks, I just don't like fixing things that aren't
> broken!

You noted later that you previously broke the cable and replaced it.

Were you 100% certain you routed the cable around the fixing bolt the
same direction it was, previously? I've seen behavior like you
mentioned when I routed the cable over the top of the bolt, versus the
bottom (or vice versa, I'm not looking at a derailleur right now).
There is a groove where the cable needs to go, and it has to be on the
right side or the cable pull will be slightly off, and shifting will be
erratic.

 

[Giga Watts]

[email protected] wrote:
> Giga Watts wrote:
> > Hello gurus!
<snipped>
> > GW
>
> Also try adjust the "B" screw on the rear derailleur (the one that
> screws up against the tab on the dropout derailleur hanger) so that
the
> jockey pulley is as close to the cogs as possible without rattling
> against them, in all gear combinations.
>
> Also use the narrowest (1.1mm) non-teflon coated cable.
>
>
> Dan Christopherson
> Lopez Island WA

Dan:

Yeah, one of the first things I tried was do to a complete alignment of
the rear derailleur -- I checked the L and H screw settings, as well as
the B-screw. Then I pulled the inner wire and cleaned and lubed it. I
also cleaned and lubed the derailleur on the pivots and the pulleys.
It was then that I saw the axial play in the G-pulley and made me
(erroneously) think that IT might be the problem. My chain is worn (I
checked at the advice of some kind posters) and I'll need to replace
that. This is rather a pain since the chain is a 10' 6" beast -- I
ride a recumbent.

I do plan to replace the housing and probably the inner wire, too.

Thanks!

GW

 

[Giga Watts]

Bill Lloyd wrote:
> On 2005-04-26 11:06:29 -0700, "Giga Watts" <[email protected]>
said:
>
> > Hello gurus!
<snipped>
> >
>
> You noted later that you previously broke the cable and replaced it.
>
> Were you 100% certain you routed the cable around the fixing bolt the

> same direction it was, previously? I've seen behavior like you
> mentioned when I routed the cable over the top of the bolt, versus
the
> bottom (or vice versa, I'm not looking at a derailleur right now).
> There is a groove where the cable needs to go, and it has to be on
the
> right side or the cable pull will be slightly off, and shifting will
be
> erratic.

Bill:

I'm not /100%/ certain, but I'm /99%/ certain that I've routed it right
I'll double check it, though.

Thanks!

GW