Newbie Q: New Shifter and R Derailleur Cable Installed - Cable Stretch?

[Jay - BFri Commuter]

30 miles ago, my LBS installed a new shifter and rear derailleur cable. As I
rode away from the shop, the shifting was fine. 30 miles hence, I need to go
too far and then come back. So I suspect the new cable has stretched. What
is the best way to tweak this? Turn the barrel shifter on the handle bars?

I would rather not bring the bike back to the shop, because he has a real
attitude during their busy season. I have noticed that he is a lot
friendlier when I ask for the same service in February (I commute year
'round in Chicago) - TIA - J.

 

[Bill Sornson]

Jay - BFri Commuter wrote:
> 30 miles ago, my LBS installed a new shifter and rear derailleur
> cable. As I rode away from the shop, the shifting was fine. 30 miles
> hence, I need to go too far and then come back. So I suspect the new
> cable has stretched. What is the best way to tweak this? Turn the
> barrel shifter on the handle bars?

Yes, but... The shifting should not deteriorate in 30 lousy miles.

> I would rather not bring the bike back to the shop, because he has a
> real attitude during their busy season. I have noticed that he is a
> lot friendlier when I ask for the same service in February (I commute
> year 'round in Chicago) - TIA - J.

Assuming you spent a fair amount of money for this recent installation
service, take it back and ask (politely demand) that it work right.

Just my opinion... BS

 

[landotter]

On Apr 28, 5:36 pm, "Jay - BFri Commuter" <[email protected]> wrote:
> 30 miles ago, my LBS installed a new shifter and rear derailleur cable. As I
> rode away from the shop, the shifting was fine. 30 miles hence, I need to go
> too far and then come back. So I suspect the new cable has stretched. What
> is the best way to tweak this? Turn the barrel shifter on the handle bars?

Turn the barrel adjuster till the jockey wheel of the derailleur is
perfectly under the selected cog. It's not difficult. My hunches are
that you'll need a half turn counterclockwise.

 

[Steven S]

Just turn the barrel adjuster lose a few turns [It may be located right on
the handlebars at the shifters or where the cable meets the derailleur or
both] to make the cable more taut until optimal shift performance is
achieved. I like using the ones on the handlebar as I can make the
adjustments while riding and test them by shifting.
"Jay - BFri Commuter" <[email protected]> wrote in message
news:[email protected]...
> 30 miles ago, my LBS installed a new shifter and rear derailleur cable. As
> I rode away from the shop, the shifting was fine. 30 miles hence, I need
> to go too far and then come back. So I suspect the new cable has
> stretched. What is the best way to tweak this? Turn the barrel shifter on
> the handle bars?
>
> I would rather not bring the bike back to the shop, because he has a real
> attitude during their busy season. I have noticed that he is a lot
> friendlier when I ask for the same service in February (I commute year
> 'round in Chicago) - TIA - J.
>

 

[[email protected]]

On Apr 28, 8:59 pm, landotter <[email protected]> wrote:
> On Apr 28, 5:36 pm, "Jay - BFri Commuter" <[email protected]> wrote:
>
> > 30 miles ago, my LBS installed a new shifter and rear derailleur cable. As I
> > rode away from the shop, the shifting was fine. 30 miles hence, I need to go
> > too far and then come back. So I suspect the new cable has stretched. What
> > is the best way to tweak this? Turn the barrel shifter on the handle bars?

Yes. Or the one where the cable enters the derailleur.

FWIW, the cable didn't literally stretch. Instead, the various curves
and endpoints of the cable and housing just settled into their final
positions, and that created a little more slack in the system.

It's a pretty common thing, and it's very easy to fix.

>
> Turn the barrel adjuster till the jockey wheel of the derailleur is
> perfectly under the selected cog. It's not difficult. My hunches are
> that you'll need a half turn counterclockwise.

Yes - although "counterclockwise" depends which end you're looking
from! You want to turn the adjuster in the direction that would
unscrew it from whatever it's screwed into. That's counterclockwise
if you're looking from the cable side of the adjuster.

BTW, I wouldn't march into the shop and act angry. IMO, the
mechanic's only sin was to forget to tell you that this adjustment
might be necessary.

- Frank Krygowski

 

[Bill Sornson]

[email protected] wrote:

> BTW, I wouldn't march into the shop and act angry. IMO, the
> mechanic's only sin was to forget to tell you that this adjustment
> might be necessary.

After 30 miles? Hmm. (BTW, who said to march in and act angry?)

 

[Jay - BFri Commuter]

"Jay - BFri Commuter" <[email protected]> wrote in message
news:[email protected]...
> 30 miles ago, my LBS installed a new shifter and rear derailleur cable. As
> I rode away from the shop, the shifting was fine. 30 miles hence, I need
> to go too far and then come back. So I suspect the new cable has
> stretched. What is the best way to tweak this? Turn the barrel shifter on
> the handle bars?
>
> I would rather not bring the bike back to the shop, because he has a real
> attitude during their busy season. I have noticed that he is a lot
> friendlier when I ask for the same service in February (I commute year
> 'round in Chicago) - TIA - J.
Thanks much guys,

I had a similar problem a few months back, and turning the barrel adjuster
at the handlebars counter-clockwise restored normal shifting while on the
repair stand, but the problem came back after riding a couple days later. I
think it came back because the cable housing on my folder was visibly
damaged in a couple places, from when I carelessly pinched it in the
kickstand when folding it. So there was more friction. The housing and inner
wire has since been replaced. Also, the cable is now routed above the BB.
(Previously, it was below.) This allows for a more generous loop at the R
derailleur, which Park says is a good idea.

I have been able to successfully replace (upgrade) my side-pull V-type
brakes (Avid Ultimate) and brake levers, check out my BB (did not need
replacing), stuff like that, with the help of you bike experts. Much of what
I have learned has been gleaned from lurking, rather than authoring my own
posts. I think replacing my chain at the .75% wear point is the most
important self-maintenance one can do for a bike. Much like car oil changes.
But derailleurs and shifters remain a mystery to me. For me, it makes sense
to have my LBS do that work.

Aside: Watching the NFL Draft on ESPN as I write this. Anyone else think
that the best thing about watching coverage of the late draft rounds is the
ESPN spots of those fake news conferences? They crack me up, even if I have
seen them before. Especially the Ditka one, where he seems to have a brain
cramp at one point. And Suzie K is not hard to look at - J.

 

[Mike Jacoubowsky]

>> BTW, I wouldn't march into the shop and act angry. IMO, the
>> mechanic's only sin was to forget to tell you that this adjustment
>> might be necessary.
>
> After 30 miles? Hmm. (BTW, who said to march in and act angry?)

Actually, if it were going to happen at all, it would likely happen fairly
quickly. One tries to pre-stress the system as much as possible, but newer
Shimano drivetrains don't allow you to apply as much pressure to the cable
(by trying to overshift) as you used to be able to do.

By the way, I'm told that cables don't actually stretch much at all. Most of
the effect apparently comes from compression of the cable housing, along
with any seating of ferrules onto the ends of the housings. This implies
that you'd have almost no issue at all if you replaced just the cables and
not the housing, but I haven't tested this to find out if it's true (since
generally, by the time the gear cables need replacement, the housing does
too).

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

 

[Bill Sornson]

Mike Jacoubowsky wrote:
>>> BTW, I wouldn't march into the shop and act angry. IMO, the
>>> mechanic's only sin was to forget to tell you that this adjustment
>>> might be necessary.
>>
>> After 30 miles? Hmm. (BTW, who said to march in and act angry?)
>
> Actually, if it were going to happen at all, it would likely happen
> fairly quickly. One tries to pre-stress the system as much as
> possible, but newer Shimano drivetrains don't allow you to apply as
> much pressure to the cable (by trying to overshift) as you used to be
> able to do.
> By the way, I'm told that cables don't actually stretch much at all.
> Most of the effect apparently comes from compression of the cable
> housing, along with any seating of ferrules onto the ends of the
> housings. This implies that you'd have almost no issue at all if you
> replaced just the cables and not the housing, but I haven't tested
> this to find out if it's true (since generally, by the time the gear
> cables need replacement, the housing does too).

Well, I suppose the mechanic could have not-quite-seated a ferrule and
adjusted the shifting, and then when it did snuggle in place the shifting
would be off abit? Still sounds like he should take it back since he just
paid to have a fair amount of work done (per OP); would take all of five
minutes to square it away. (Of course. once the OP learns how to do some
stuff himself, then he'll just fix it.)

 

[Mike Jacoubowsky]

> Well, I suppose the mechanic could have not-quite-seated a ferrule and
> adjusted the shifting, and then when it did snuggle in place the shifting
> would be off abit? Still sounds like he should take it back since he just
> paid to have a fair amount of work done (per OP); would take all of five
> minutes to square it away. (Of course. once the OP learns how to do some
> stuff himself, then he'll just fix it.)

Absolutely agree that, if it's not too inconvenient, it should be taken back
to the shop that did the work. If the shop has the sort of attitude about
such things that you wouldn't want to do so, I'd find a different shop.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Bill Sornson" <[email protected]> wrote in message
news:[email protected]...
> Mike Jacoubowsky wrote:
>>>> BTW, I wouldn't march into the shop and act angry. IMO, the
>>>> mechanic's only sin was to forget to tell you that this adjustment
>>>> might be necessary.
>>>
>>> After 30 miles? Hmm. (BTW, who said to march in and act angry?)
>>
>> Actually, if it were going to happen at all, it would likely happen
>> fairly quickly. One tries to pre-stress the system as much as
>> possible, but newer Shimano drivetrains don't allow you to apply as
>> much pressure to the cable (by trying to overshift) as you used to be
>> able to do.
>> By the way, I'm told that cables don't actually stretch much at all.
>> Most of the effect apparently comes from compression of the cable
>> housing, along with any seating of ferrules onto the ends of the
>> housings. This implies that you'd have almost no issue at all if you
>> replaced just the cables and not the housing, but I haven't tested
>> this to find out if it's true (since generally, by the time the gear
>> cables need replacement, the housing does too).
>
> Well, I suppose the mechanic could have not-quite-seated a ferrule and
> adjusted the shifting, and then when it did snuggle in place the shifting
> would be off abit? Still sounds like he should take it back since he just
> paid to have a fair amount of work done (per OP); would take all of five
> minutes to square it away. (Of course. once the OP learns how to do some
> stuff himself, then he'll just fix it.)
>

 

[Bill Sornson]

Mike Jacoubowsky wrote:
{I wrote}
>> Well, I suppose the mechanic could have not-quite-seated a ferrule
>> and adjusted the shifting, and then when it did snuggle in place the
>> shifting would be off abit? Still sounds like he should take it
>> back since he just paid to have a fair amount of work done (per OP);
>> would take all of five minutes to square it away. (Of course. once
>> the OP learns how to do some stuff himself, then he'll just fix it.)

> Absolutely agree that, if it's not too inconvenient, it should be
> taken back to the shop that did the work. If the shop has the sort of
> attitude about such things that you wouldn't want to do so, I'd find
> a different shop.

Yup.

 

[landotter]

On Apr 30, 12:04 am, "Mike Jacoubowsky" <[email protected]> wrote:
> >> BTW, I wouldn't march into the shop and act angry. IMO, the
> >> mechanic's only sin was to forget to tell you that this adjustment
> >> might be necessary.
>
> > After 30 miles? Hmm. (BTW, who said to march in and act angry?)
>
> Actually, if it were going to happen at all, it would likely happen fairly
> quickly. One tries to pre-stress the system as much as possible, but newer
> Shimano drivetrains don't allow you to apply as much pressure to the cable
> (by trying to overshift) as you used to be able to do.
>
> By the way, I'm told that cables don't actually stretch much at all. Most of
> the effect apparently comes from compression of the cable housing, along
> with any seating of ferrules onto the ends of the housings.

Yeah, but calling it "housing compression and ferrule seating" doesn't
get the same rise out of Jobst...

 

[Jay - BFri Commuter]

"Jay - BFri Commuter" <[email protected]> wrote in message
news:[email protected]...
> "Jay - BFri Commuter" <[email protected]> wrote in message
> news:[email protected]...
>> 30 miles ago, my LBS installed a new shifter and rear derailleur cable.
>> As I rode away from the shop, the shifting was fine. 30 miles hence, I
>> need to go too far and then come back. So I suspect the new cable has
>> stretched. What is the best way to tweak this? Turn the barrel shifter on
>> the handle bars?
>>
>> I would rather not bring the bike back to the shop, because he has a real
>> attitude during their busy season. I have noticed that he is a lot
>> friendlier when I ask for the same service in February (I commute year
>> 'round in Chicago) - TIA - J.
> Thanks much guys,
>
> I had a similar problem a few months back, and turning the barrel adjuster
> at the handlebars counter-clockwise restored normal shifting while on the
> repair stand, but the problem came back after riding a couple days later.
> I think it came back because the cable housing on my folder was visibly
> damaged in a couple places, from when I carelessly pinched it in the
> kickstand when folding it. So there was more friction. The housing and
> inner wire has since been replaced. Also, the cable is now routed above
> the BB. (Previously, it was below.) This allows for a more generous loop
> at the R derailleur, which Park says is a good idea.
>
> I have been able to successfully replace (upgrade) my side-pull V-type
> brakes (Avid Ultimate) and brake levers, check out my BB (did not need
> replacing), stuff like that, with the help of you bike experts. Much of
> what I have learned has been gleaned from lurking, rather than authoring
> my own posts. I think replacing my chain at the .75% wear point is the
> most important self-maintenance one can do for a bike. Much like car oil
> changes. But derailleurs and shifters remain a mystery to me. For me, it
> makes sense to have my LBS do that work.
>
All,

I gave the barrel adjuster a half-twist counter-clockwise, and the shifting
is much better. I will note how it shifts in the next few days, and tweak as
necessary.

Thanks for the detailed explanations of what is going on, as well as how to
fix it. Even if the actual repairs are beyond my ability at this point, I
hope someday to be able to replace my shifters and derailleur myself. Mostly
as a hobby, and for the convenience of being able to do my own work, rather
than going to the shop. If my bike is in the shop, I am walking until I get
it back - J.