Unwanted upshifting from 4th to fifth cog

I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

BC
shifty

bcdrums wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

The first thing I check when shifting gets dodgy is the cable tension. I
shift to the smallest rear cog and check the shifter cable (the cable,
not the housing) to see if there's any slack. If so, I loosen the cable
clamp on the rear der and tug the looseness out of the cable.*

This might not work for you, of course, because you might have something
else going on, but it's generally my go-to procedure.

==========
* There are barrel tensioner-like thingies on where the der cables exit
the shifters but those have never done anything useful, near as I can
tell -- I'm not even certain what they are there for.

--
Mike "Rocket J Squirrel"
Bend, Oregon

bcdrums wrote:

I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

Have a look at Sheldon's article:
http://www.sheldonbrown.com/autoshift.html

John

On 5/1/10 3:06 PM, Mike Elliott wrote:
bcdrums wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I
shift from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

The first thing I check when shifting gets dodgy is the cable tension. I
shift to the smallest rear cog and check the shifter cable (the cable,
not the housing) to see if there's any slack. If so, I loosen the cable
clamp on the rear der and tug the looseness out of the cable.*

This might not work for you, of course, because you might have something
else going on, but it's generally my go-to procedure.

==========
* There are barrel tensioner-like thingies on where the der cables exit
the shifters but those have never done anything useful, near as I can
tell -- I'm not even certain what they are there for.


Mike,

I did check the cable tension at your suggestion. It seems okay- it
shifts up and down correctly across all cogs while on the stand (of
course it does!).

In case you are not just putting my leg on about the barrel adjuster, I
will send you to Sheldon for his explanation of its purpose.

http://www.sheldonbrown.com/derailer-adjustment.html

As it turns out, Sheldon also has an article on spontaneous upshifting-
which is my problem. I read it, and he said that the most frequent cause
is a sticky cable at the bottom bracket, exacerbated by a strong heavy
rider (which I am not). I will check this out too.

BC
Sheldon fan

On 5/1/10 3:50 PM, John Henderson wrote:
bcdrums wrote:

I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

Have a look at Sheldon's article:
http://www.sheldonbrown.com/autoshift.html

John

John, thanks. Coincidentally, I came upon this article.

BC

bcdrums wrote:
On 5/1/10 3:06 PM, Mike Elliott wrote:
bcdrums wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I
shift from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

The first thing I check when shifting gets dodgy is the cable tension. I
shift to the smallest rear cog and check the shifter cable (the cable,
not the housing) to see if there's any slack. If so, I loosen the cable
clamp on the rear der and tug the looseness out of the cable.*

This might not work for you, of course, because you might have something
else going on, but it's generally my go-to procedure.

==========
* There are barrel tensioner-like thingies on where the der cables exit
the shifters but those have never done anything useful, near as I can
tell -- I'm not even certain what they are there for.


Mike,

I did check the cable tension at your suggestion. It seems okay- it
shifts up and down correctly across all cogs while on the stand (of
course it does!).

In case you are not just putting my leg on about the barrel adjuster, I
will send you to Sheldon for his explanation of its purpose.

http://www.sheldonbrown.com/derailer-adjustment.html


I can't dispute St. Sheldon. This is probably a case of a loose nut on
the saddle. Me.


--
Mike "Rocket J Squirrel"
Bend, Oregon

On 1 May, 19:36, bcdrums wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

BC
shifty

Twisted frame ends. Loose mechanism mounting bolt, favoutrite. Bolt
up mech and the axle super tight then adjust cable length in the dodgy
gears so that the pulley lines up with the sprocket. No9 need to test
on a stand, just ride it.

"bcdrums" wrote in message
...
On 5/1/10 3:06 PM, Mike Elliott wrote:
bcdrums wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I
shift from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

The first thing I check when shifting gets dodgy is the cable tension. I
shift to the smallest rear cog and check the shifter cable (the cable,
not the housing) to see if there's any slack. If so, I loosen the cable
clamp on the rear der and tug the looseness out of the cable.*

This might not work for you, of course, because you might have something
else going on, but it's generally my go-to procedure.

==========
* There are barrel tensioner-like thingies on where the der cables exit
the shifters but those have never done anything useful, near as I can
tell -- I'm not even certain what they are there for.


Mike,

I did check the cable tension at your suggestion. It seems okay- it shifts
up and down correctly across all cogs while on the stand (of course it
does!).

In case you are not just putting my leg on about the barrel adjuster, I
will send you to Sheldon for his explanation of its purpose.

http://www.sheldonbrown.com/derailer-adjustment.html

As it turns out, Sheldon also has an article on spontaneous upshifting-
which is my problem. I read it, and he said that the most frequent cause
is a sticky cable at the bottom bracket, exacerbated by a strong heavy
rider (which I am not). I will check this out too.

BC
Sheldon fan

Cytomax dripping down a shift cable has been the cause of many shifting
issues. Funny that you can get better shifting by using a bottle that seals
better. :-)

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

On 5/1/10 4:08 PM, thirty-six wrote:
On 1 May, 19:36, wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

BC
shifty

Twisted frame ends.

If so, it's not obvious.

Loose mechanism mounting bolt, favoutrite.

Checked at your suggestion. Not loose.

Bolt
up mech and the axle super tight then adjust cable length in the dodgy
gears so that the pulley lines up with the sprocket.

Lines up well.

No9 need to test
on a stand, just ride it.

Agreed!

BC
bolting

On 1 May, 21:16, bcdrums wrote:
On 5/1/10 4:08 PM, thirty-six wrote:



On 1 May, 19:36, *wrote:
I have a typical 9 speed triple road setup, all Shimano except for a
SRAM chain. I have bar-end shifters, not brifters. Lately, after I shift
from cog 3 to 4, moments later the chain will drop to 5.

I adjusted the cable length on the derailler to make the cable longer,
but that did not help. I checked the chain for elongation, but it is
only about 1/32" long. I looked at the cogs for a clue, but they don't
appear to be very worn, or perhaps I am not seeing it.
About a month ago I changed the cables and housings for the brakes and
shifters, but the problem is more recent.

Any suggestions as to what might be causing this?

BC
shifty

Twisted frame ends.

If so, it's not obvious.

Loose mechanism mounting bolt, favoutrite.

Checked at your suggestion. Not loose.

Bolt

up mech and the axle super tight then adjust cable length in the dodgy
gears so that the pulley lines up with the sprocket.

Lines up well.

No9 need to test

on a stand, just ride it.

Agreed!

BC
bolting

If the problem continues, then I suspect the cable is sticking
somewhere, either due to wear, lack of lubricant, dirt or a kink. Use
a light graphited spray on gear cables.