Derailleur Question

Marian says...

Quoted message said:

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws. It
generally performs better when shifting to a bigger gear than a smaller
gear but lots of times it just doesn't want to shift ... I'll have to
click twice and back one to get a shift ... sometimes three times. The
wrench is saying I'm going to need to get a new derailleur eventually
because this one is beyond repair and while they are perfectly willing
to keep adjusting it for me on a regular basis (to the extent of
teaching me how to adjust it myself going on the list of things to
learn) it is never going to shift smoothly again.

So, I'm doing what I always do when I'm not entirely sure I agree with
what the wrench has said. Asking rec.bicycles.tech for help...

Shifting problems like yours can have many causes including sticky
shifters, sticky cables or a sticky derailleur. The condition of the
chain and gears are also major contributors. It probably shifts to the
bigger gears better because in that case you are increasing the cable
tension instead of decreasing it as when going to a smaller gear. When
going to a smaller gear the derailleur spring must overcome the total
drag and friction from the shifters, cables and derailleur. If there is
a lot of friction or if the derailleur is bent and out of line, it may
not go anywhere. Even with a new derailleur, the total repair shouldn't
be all that expensive.

Marian said:

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws.

This does sound like sticky stuff in your shifting system, as Barnard
F. suggests, but 1st I would have the shop check the derailleur hanger
alignment & align it if necessary. Also check the alignment of the
derailleur it's self. I have 2 ways I've attempted this. One way to do
this is, after the hanger is aligned, is to align the seat tube to be
plumb w/ a torpedo level & then check the pulleys for plumb. I've also,
after hanger alignment, put the bike in a gear combo. That has the
chain @ the same distance from the ctr. line @ both front & rear, &
then sight the chain w/ the 2 pulleys. If someone has a better plan I
would certainly like to know about it, because I don't think these are
a very good ways to do it.

Also I've been pleasantly surprised many times by how much cleaning &
lubing the chain & teeth, helps. I mean I know intellectually that it
helps, but the need creeps up & often seems like it might be another
problem until cleaning & lubing is performed.

Regards, John

Barnard Frederick said:

Marian says...

Quoted message said:

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws.

... When
going to a smaller gear the derailleur spring must overcome the total
drag and friction from the shifters, cables and derailleur. If there is
a lot of friction or if the derailleur is bent and out of line, it may
not go anywhere. Even with a new derailleur, the total repair shouldn't
be all that expensive.

I'd swap out the der cable first (making sure that good-quality
*derailleur* housing is used, not cheap spiral-wrapped unlined brake
housing), and if that doesn't solve the probelm, then replace the der,
given the symptoms.
--
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Marian said:

Quoting Sheldon Brown's website "Well-intentioned folks sometimes try
to correct this by grabbing hold of the derailer and trying to pull it
back outward to its proper position. Unfortunately, they usually wind
up yanking on the derailer by its cage, which is the weakest part. As a
result, they fail to straigten the bent hanger, and, instead, bend the
cage as well."

This has been done to my derailleur a couple few more times than I'd
like to think about. Generally not by the competent mechanics, but it
has been done rather a lot. In the days before I first had about two
inches cut off of my kickstand and then simply removed it my bike fell
down on the derailleur frequently and that was usually one of the first
things done before adjusting it.

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws. It
generally performs better when shifting to a bigger gear than a smaller
gear but lots of times it just doesn't want to shift ... I'll have to
click twice and back one to get a shift ... sometimes three times. The
wrench is saying I'm going to need to get a new derailleur eventually
because this one is beyond repair and while they are perfectly willing
to keep adjusting it for me on a regular basis (to the extent of
teaching me how to adjust it myself going on the list of things to
learn) it is never going to shift smoothly again.

So, I'm doing what I always do when I'm not entirely sure I agree with
what the wrench has said. Asking rec.bicycles.tech for help...

-M

Do the cheapest first..new cables and housing, clean under BB guide, if
applicable. THEN look at the RD....Last, maybe the shifter,
particularly if STI or ERGO...

Barnard Frederick said:

Marian says...

Quoted message said:

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws. It
generally performs better when shifting to a bigger gear than a smaller
gear but lots of times it just doesn't want to shift ... I'll have to
click twice and back one to get a shift ... sometimes three times. The
wrench is saying I'm going to need to get a new derailleur eventually
because this one is beyond repair and while they are perfectly willing
to keep adjusting it for me on a regular basis (to the extent of
teaching me how to adjust it myself going on the list of things to
learn) it is never going to shift smoothly again.

So, I'm doing what I always do when I'm not entirely sure I agree with
what the wrench has said. Asking rec.bicycles.tech for help...

Shifting problems like yours can have many causes including sticky
shifters, sticky cables or a sticky derailleur. The condition of the
chain and gears are also major contributors. It probably shifts to the
bigger gears better because in that case you are increasing the cable
tension instead of decreasing it as when going to a smaller gear.

Yikes, Sheldon-esque again!! 'Bigger' gears are smaller cogs, 'smaller'
gears are bigger cogs, think of a car-high gear is 5th, low gear is
first

When

Quoted message said:

going to a smaller gear the derailleur spring must overcome the total
drag and friction from the shifters, cables and derailleur. If there is
a lot of friction or if the derailleur is bent and out of line, it may
not go anywhere. Even with a new derailleur, the total repair shouldn't
be all that expensive.

Marian said:

what the wrench has said. Asking rec.bicycles.tech for help...

-M

Something is sticking .. I doubt it needs to be replaced

First.. clean it really well and lube everything.. pay close attention
to the pivot points on the derailleurs body use a very light oil ATF,
penetrating or machine oil on these points.

I don't know how handy you are but I would drop it of the bike entirely
to do this but you can also take the chain off the front sprockets and
then simply move the derailleur body back and forth a bunch with your
hands I would bet that it is stiff at this point and needs to be worked
to free up.

While you have the light oil out, lube the cable..

Everyone else in the thread so far is correct about the next steps
...(replace cable and housing) but I didn't notice this mentioned ..

john said:

Marian said:

Recently I've started having shifting problems that don't want to go
away no matter how much they fuss with the adjustment screws.

This does sound like sticky stuff in your shifting system, as Barnard
F. suggests, but 1st I would have the shop check the derailleur hanger
alignment & align it if necessary.

When I'm physically up to trying to ride in anything other than the
lowest gear I'll let you know if crashing and forcing the derailleur
hanger to be replaced altogether helped with the shifting any...

-M

Rear derailleurs wear out. You get wear in the pivots and end up with a
condition as you describe. Unless you can figure out a way to press out the
old pivot pins and then fix the problem, you will need to get a new derailleur.
-------------
Alex

Alex Rodriguez said:

Rear derailleurs wear out. You get wear in the pivots and end up with a
condition as you describe. Unless you can figure out a way to press out the
old pivot pins and then fix the problem, you will need to get a new derailleur.

My immediate feeling is "but I've barely even had it 6 months," then it
occured to me that those 6 months have included my first ever multi-day
tour, an international multi day tour, my first and second centuries,
and the racer boys bullying me ... so here comes the next question - is
8000 km a reasonable lifespan for a Shimano Sora derailleur? Or have I
been doing something wrong?

-M