diagnosing a sluggish rear derailleur

Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly appreciated....

On 19 Dec 2006 07:39:37 -0800, "BillJosephson"
wrote:

Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

lube it thats the usual cause. or the cable needs lubed or replaced.

BillJosephson wrote:
Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly appreciated....

Sounds like a sticky cable. See
http://sheldonbrown.com/derailer-adjustment.html#cable

A worn chain and cassette can cause sluggish shifting, too, but try
replacing the cable and housing first.

-Vee

BillJosephson wrote:

I have a Sachs rear derailleur, with index shifting via
twisting handgrip. When I shift to a smaller gear in the back,
it may take seconds for the shift to take place. When I watch
the rear while shifting, the cage moves very slowly. If I push
the cage toward the spokes with my thumb, it immediately
springs back out to its limit. I don't see any place where the
cable could be binding. It's also extremely hard to shift to
bigger gears in back now. I've had this bike about 1 year,
ride it an hour most days in the morning. When I got it (from
a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly
appreciated....

One reason that the cable may be binding is that it's starting
to break up. Broken individual strands at the affected site
will bind in the conduit or housing and cause the problems
you're seeing.

Replacing the inner with a new one is generally easier than
refitting the old one if that's completely removed for
inspection.

Have you checked the chain for excessive wear? This can cause
sluggish shifting (but not slow movement of the derailleur
cage).

John

BillJosephson wrote:
Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly appreciated....

Clean and grease where the cable goes under the bottom bracket might help.

BillJosephson wrote:
Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this
bike about 1 year, ride it an hour most days in the morning. When I
got it (from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly
appreciated....

The pivots derailleur itself may be gummed up. Try lubing the pivots
while moving the derailleur across its range over and over.

--
Phil

BillJosephson wrote:
Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly appreciated....

new inner wire and 5mm housing and a bassworm..helps gripshift a lot.

BillJosephson wrote:
Hello...

I have a Sachs rear derailleur, with index shifting via twisting
handgrip. When I shift to a smaller gear in the back, it may take
seconds for the shift to take place. When I watch the rear while
shifting, the cage moves very slowly. If I push the cage toward the
spokes with my thumb, it immediately springs back out to its limit. I
don't see any place where the cable could be binding. It's also
extremely hard to shift to bigger gears in back now. I've had this bike
about 1 year, ride it an hour most days in the morning. When I got it
(from a friend) it shifted crisply and easily, amazingly so.

Any suggestions on what to look at next would be greatly appreciated....

sticky cable. clean, replace housing, and use a ferrule that has a seal
in it.