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Keep Breaking Shifter Cables - Why?



 
 
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  #1  
Old September 8th 09, 02:03 AM posted to rec.bicycles.tech
Steve Sr.
external usenet poster
 
Posts: 203
Default Keep Breaking Shifter Cables - Why?

Hello,

I have a 10-speed Ultegra equipped road bike in which the rear
deraileur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about 3/4"
from the barrel. This is currently happening every 3000 miles or so.

Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided to
opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano inner
wire. Also at this time I replaced the plastic ferrules with the
aluminum variety as recommended by the LBS that sold me the cable.

Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event next
weekend. Much to my surprise I found a broken strand in the new
Shimano cable necessitating yet another cable replacement.

When removing the old cable rather than unwinding the broken strand I
picked up a pair of regular needle nose pliers that happened to have
side cutters built in and to my amazement these cutters went right
through the cable! In the past I can remember these steel cables being
un-cutable by this method. For identification purposes the side of
the cable barrel has an "R" stamped in the side of it.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know which
one best and which one I am getting?

Any other things that I should check that might be causing these
premature cable failures?


Thanks,

Steve
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  #2  
Old September 8th 09, 02:13 AM posted to rec.bicycles.tech
AMuzi
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Posts: 9,639
Default Keep Breaking Shifter Cables - Why?

Steve Sr. wrote:
Hello,

I have a 10-speed Ultegra equipped road bike in which the rear
deraileur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about 3/4"
from the barrel. This is currently happening every 3000 miles or so.

Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided to
opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano inner
wire. Also at this time I replaced the plastic ferrules with the
aluminum variety as recommended by the LBS that sold me the cable.

Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event next
weekend. Much to my surprise I found a broken strand in the new
Shimano cable necessitating yet another cable replacement.

When removing the old cable rather than unwinding the broken strand I
picked up a pair of regular needle nose pliers that happened to have
side cutters built in and to my amazement these cutters went right
through the cable! In the past I can remember these steel cables being
un-cutable by this method. For identification purposes the side of
the cable barrel has an "R" stamped in the side of it.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know which
one best and which one I am getting?

Any other things that I should check that might be causing these
premature cable failures?


Both Shimano and Jaguar make various grades of gear wire.
Do you replace the casing with a new wire?

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
  #3  
Old September 8th 09, 02:14 AM posted to rec.bicycles.tech
tiborg
external usenet poster
 
Posts: 65
Default Keep Breaking Shifter Cables - Why?

On Sep 8, 10:03*am, Steve Sr. wrote:
Hello,

I have a 10-speed Ultegra equipped road bike in which the rear
deraileur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about 3/4"
from the barrel. This is currently happening every 3000 miles or so.

Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided to
opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano inner
wire. Also at this time I replaced the plastic ferrules with the
aluminum variety as recommended by the LBS that sold me the cable.

Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event next
weekend. *Much to my surprise I found a broken strand in the new
Shimano cable necessitating yet another cable replacement.

When removing the old cable rather than unwinding the broken strand I
picked up a pair of regular needle nose pliers that happened to have
side cutters built in and to my amazement these cutters went right
through the cable! In the past I can remember these steel cables being
un-cutable by this method. *For identification purposes the side of
the cable barrel has an "R" stamped in the side of it.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know which
one best and which one I am getting?

Any other things that I should check that might be causing these
premature cable failures?

Thanks,

Steve


3000 miles between breaks in the rear shifter is the norm for me. Now
I just replace the cables after 2000 miles whether or not they have
started to break, just so I can avoid the inevitable break on the
road. I've used shimano and no-brand cables, doesn't seem to make any
difference.
  #4  
Old September 8th 09, 09:36 AM posted to rec.bicycles.tech
Chalo
external usenet poster
 
Posts: 4,943
Default Keep Breaking Shifter Cables - Why?

Steve Sr. wrote:

I have a 10-speed Ultegra equipped road bike


That's why.

  #5  
Old September 8th 09, 10:26 PM posted to rec.bicycles.tech
Mike Jacoubowsky
external usenet poster
 
Posts: 2,972
Default Keep Breaking Shifter Cables - Why?

Mike Jacoubowsky wrote:
{snip}

One of the variables we've recently found responsible for shortening
cable life is the use of drink mixes in the downtube water bottle,
which will sometimes get on the gear cable and run down to the bottom
bracket cable guide, where it will cause a lot of increased friction
in the system. Another is worn shift cable housing; I'd recommend
replacing the housing at the same time as the cable. And if neither
of those are responsible for your cables breaking, it's possible you
have a lever that simply likes to eat cables. Shimano admits that
there are some out there, and they'll replace, on a case-by-case
basis, levers that are no longer functional because a cable has
broken off inside the lever and the head cannot be removed.


This true of both 9- and 10-speed systems? Sure seems to be the case with
/my/ 9-ers -- and always at the lowest altitude point of my rides!
(Literally -- breaks have occurred at bottom of steep climbs with long
ways to go after that.)


No, this is a 10-speed-only issue. Not to say that 9-speed levers don't get
cable failures- they do- but there's little variability between one lever
and the next. There is evidence that some 10-speed levers are more prone to
breaking cables than others.

My Ultegra 9 rear shifter broke off a cable head at least once; and my
Dura-Ace rear brifter -- replaced once under warranty after breaking off a
head and then crapping out -- broke another one just last week. Got the
head out after some doing and it seems OK now, but that's at least 3 gear
cables that have lost heads (might be one more) on two bikes in 3-4 years.


But how many miles of use? 7,000 miles would be a fairly normal lifetime for
a rear shifter cable, based upon my own personal observations. I actually do
better than that, but I try to make sure they're running smoothly and keep
them lubed at the bottom bracket cable guide (where drink mix & road gunk
conspire to create friction).

I thought I heard something about defective cables, too, but these have
been various brands (Shimano, Aztec, Jagwire, etc.).


At one point there were supposedly some bad Shimano cables, but they were
recalled and dealt with long ago.

Back in my active mountain biking days, I also used to break rear cables,
but always right at the derailleur. Finally got a pair of Shift Mates (is
that what they're called? -- little wheel dealie that replaced last bit of
housing) and both mtbs have been fine since. (One 8-speed; other 9-.)

Bill "ham handed" S.


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

  #6  
Old September 8th 09, 11:00 PM posted to rec.bicycles.tech
Bill Bushnell
external usenet poster
 
Posts: 121
Default Keep Breaking Shifter Cables - Why?

Bill Sornson wrote:
Mike Jacoubowsky wrote:
{snip}


One of the variables we've recently found responsible for shortening
cable life is the use of drink mixes in the downtube water bottle,
which will sometimes get on the gear cable and run down to the bottom
bracket cable guide, where it will cause a lot of increased friction
in the system. Another is worn shift cable housing; I'd recommend
replacing the housing at the same time as the cable. And if neither
of those are responsible for your cables breaking, it's possible you
have a lever that simply likes to eat cables. Shimano admits that
there are some out there, and they'll replace, on a case-by-case
basis, levers that are no longer functional because a cable has
broken off inside the lever and the head cannot be removed.


This true of both 9- and 10-speed systems? Sure seems to be the case with
/my/ 9-ers -- and always at the lowest altitude point of my rides!
(Literally -- breaks have occurred at bottom of steep climbs with long ways
to go after that.)


That happened a few times for me and is one of the reasons I switched to
"low-normal" rear derailers. On one occasion this occurred about 25 miles
from home. I was too lazy to stop and move the set screw to force a higher
gear or implement some other temporary fix. Limited to about 16mph maximum
speed (spinning at about 120 rpm). I found myself home only about 5-10
minutes later than I expected.

My Ultegra 9 rear shifter broke off a cable head at least once; and my
Dura-Ace rear brifter -- replaced once under warranty after breaking off a
head and then crapping out -- broke another one just last week. Got the
head out after some doing and it seems OK now, but that's at least 3 gear
cables that have lost heads (might be one more) on two bikes in 3-4 years.


I thought I heard something about defective cables, too, but these have been
various brands (Shimano, Aztec, Jagwire, etc.).


When I used SunTour's bar-end shifters and later Shimano Rapid-Fire shifters,
the cable would always break within 3cm of the shifter end barrel and appeared
to break at a location where the cable was making a sharp turn in the shifter
mechanism. I'd get about 4000-5000 miles on rear shift cables (QBP
"stainless") with these shifters, and I shift frequently.

Since I switched to using SRAM Grip Shifters I haven't broken a rear cable
yet, and one of my bikes has over 12k miles with the same rear shift cable. A
recent inspection showed no sharp bends in the cable and no broken strands.

--
Bill Bushnell
http://pobox.com/~bushnell/
  #7  
Old September 9th 09, 02:41 AM posted to rec.bicycles.tech
Steve Sr.
external usenet poster
 
Posts: 203
Default Keep Breaking Shifter Cables - Why?

On Mon, 07 Sep 2009 20:13:03 -0500, AMuzi wrote:

Steve Sr. wrote:
Hello,

I have a 10-speed Ultegra equipped road bike in which the rear
deraileur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about 3/4"
from the barrel. This is currently happening every 3000 miles or so.

Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided to
opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano inner
wire. Also at this time I replaced the plastic ferrules with the
aluminum variety as recommended by the LBS that sold me the cable.

Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event next
weekend. Much to my surprise I found a broken strand in the new
Shimano cable necessitating yet another cable replacement.

When removing the old cable rather than unwinding the broken strand I
picked up a pair of regular needle nose pliers that happened to have
side cutters built in and to my amazement these cutters went right
through the cable! In the past I can remember these steel cables being
un-cutable by this method. For identification purposes the side of
the cable barrel has an "R" stamped in the side of it.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know which
one best and which one I am getting?

Any other things that I should check that might be causing these
premature cable failures?


Both Shimano and Jaguar make various grades of gear wire.
Do you replace the casing with a new wire?


No the casing has not been replaced. How would one know if it needed
replacing?


Thanks,

Steve
  #8  
Old September 9th 09, 02:54 AM posted to rec.bicycles.tech
Steve Sr.
external usenet poster
 
Posts: 203
Default Keep Breaking Shifter Cables - Why?

On 08 Sep 2009 01:31:55 GMT, Jobst Brandt wrote:

Steve who? wrote:

I have a 10-speed Ultegra equipped road bike in which the rear
derailleur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about
3/4" from the barrel. This is currently happening every 3000 miles
or so.


Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided
to opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano
inner wire. Also at this time I replaced the plastic ferrules with
the aluminum variety as recommended by the LBS that sold me the
cable.


Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event
next weekend. Much to my surprise I found a broken strand in the
new Shimano cable necessitating yet another cable replacement.


As You probably noticed, a new cable cannot be broken with all the
force possible with a shift lever. Bowden cables break when a strand
on the inside of a (sharp) curve wears half way through. Because all
strands pass that point when shifted, they are all worn half through
in the inside of the curve and can then be easily broken by bending
under even light tension.

When removing the old cable rather than unwinding the broken strand
I picked up a pair of regular needle nose pliers that happened to
have side cutters built in and to my amazement these cutters went
right through the cable! In the past I can remember these steel
cables being un-cutable by this method. For identification purposes
the side of the cable barrel has an "R" stamped in the side of it.


Cutting with diagonal cutters (the kind you used) is good practice and
does not splay the cable, because the cable snaps back to its helical
wound shape. The important thing is to get rid of that sharp bend
where the break occurs. That is usually a kink in the cable housing,
so get a new one or cut the old ones kinked end off. The same goes
for brake cables. If you see a cable housing come off its anchor at
an angle, that is a sharp (damaging) bend for the cable.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know
which one best and which one I am getting?


There are various kinds with different strand diameters, single wound
and compound wound. Compound wound is often used to make the control
cable more flexible, something we inherited from the short bends used
for cables that follow handle bar contours. The were first common on
Campagnolo bar end shifters.

Any other things that I should check that might be causing these
premature cable failures?


Do it!

Jobst Brandt


Jobst,

I don't see any obvious bend in the housing near the broken strand but
I will probably replace the housing anyway. The main bend I see in the
inner wire is where the cable wraps around the drum in the shifter
itself.

Steve
  #9  
Old September 9th 09, 03:03 AM posted to rec.bicycles.tech
Steve Sr.
external usenet poster
 
Posts: 203
Default Keep Breaking Shifter Cables - Why?

On Mon, 7 Sep 2009 22:40:35 -0700, "Mike Jacoubowsky"
wrote:

"Steve Sr." wrote in message
.. .
Hello,

I have a 10-speed Ultegra equipped road bike in which the rear
deraileur cable keeps breaking strands near the shifter which
necessitates a cable replacement. The broken strands occur about 3/4"
from the barrel. This is currently happening every 3000 miles or so.

Originally I was using Jagwire replacement wires as that seems to be
what most local shops now carry. At the last replacement I decided to
opt for real Shimano inner wires. When removing the old cable I
compared the cable diameter and found that the Jagwire inner wires
were .010-.015" smaller in diameter compared to the new Shimano inner
wire. Also at this time I replaced the plastic ferrules with the
aluminum variety as recommended by the LBS that sold me the cable.

Fast forward about 6 months. This weekend I was cleaning and
inspecting the bike in preparation for the upcoming MS 150 event next
weekend. Much to my surprise I found a broken strand in the new
Shimano cable necessitating yet another cable replacement.

When removing the old cable rather than unwinding the broken strand I
picked up a pair of regular needle nose pliers that happened to have
side cutters built in and to my amazement these cutters went right
through the cable! In the past I can remember these steel cables being
un-cutable by this method. For identification purposes the side of
the cable barrel has an "R" stamped in the side of it.

So is this a characteristic of the newer cables or does Shimano have
several different grades of shifter cables? If so how do I know which
one best and which one I am getting?

Any other things that I should check that might be causing these
premature cable failures?


Thanks,

Steve


One of the variables we've recently found responsible for shortening cable
life is the use of drink mixes in the downtube water bottle, which will
sometimes get on the gear cable and run down to the bottom bracket cable
guide, where it will cause a lot of increased friction in the system.
Another is worn shift cable housing; I'd recommend replacing the housing at
the same time as the cable. And if neither of those are responsible for your
cables breaking, it's possible you have a lever that simply likes to eat
cables. Shimano admits that there are some out there, and they'll replace,
on a case-by-case basis, levers that are no longer functional because a
cable has broken off inside the lever and the head cannot be removed.

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


Mike,

I know about the sports drink issue and don't believe that this is a
contributing factor in my case.

The lever is probably about 2-3 years old right now so out of warranty
unless it is extended for this issue. So far I have been able to catch
the failures without completely breaking a cable and getting the head
stuck in the shifter. One broken strand is enough to be noticeable. I
cant see how anyone could let it go to complete cable breakage without
noticing shifting issues.

Steve
  #10  
Old September 9th 09, 03:25 AM posted to rec.bicycles.tech
Bill Sornson[_5_]
external usenet poster
 
Posts: 1,541
Default Keep Breaking Shifter Cables - Why?

{snippage taken}
Mike Jacoubowsky wrote:
I wrote:


My Ultegra 9 rear shifter broke off a cable head at least once; and
my Dura-Ace rear brifter -- replaced once under warranty after
breaking off a head and then crapping out -- broke another one just
last week. Got the head out after some doing and it seems OK now,
but that's at least 3 gear cables that have lost heads (might be one
more) on two bikes in 3-4 years.


But how many miles of use? 7,000 miles would be a fairly normal
lifetime for a rear shifter cable, based upon my own personal
observations. I actually do better than that, but I try to make sure
they're running smoothly and keep them lubed at the bottom bracket
cable guide (where drink mix & road gunk conspire to create friction).


Yes, guilty as charged (gently as it was). This last time, for sure, I
ignored signs that there was a problem (shifting got sketchy and I just
adjusted cable tension) and paid for it by single-speeding 20 miles home.
(Too lazy to use limit screws. God gave me a triple for good reason.) Not
sure of mileage before break, but way over 7,000 I'm sure...

Bill "and let's not discuss ignoring CHAIN wear" S.


 




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