Gear cable frayed through at shifter

Secteur

All sorted now, but thought I'd share today's mechanical.

Bit of an unusual one this morning - my rear derailleur wasn't shifting well on my ride yesterday (fine before that) - after some inspection I eventually traced the problem not to the derailleur itself, but back up to my Ultegra 6800 shifter.

Where the cable emerges from the shifter (before it routes into the cable outer & goes under the bar tape) there is a channel for the cable to run in - at this spot the cable was terribly frayed and in actual fact completely split as I was tinkering with it.

I found this odd as there is no obvious friction point, and the shifter itself looks healthy, so ?faulty cable. I have been riding on this cable / shifter from factory new some 18 months ago and never knowingly had a problem.

Anyway, I have re-cabled it now and it's all fine and will keep a close eye on the shifter to see if the new cable frays in the same place, though I cant see how it could.


EDIT: photo from the Bike Radar pages - this is where the fraying occured (the grey channel, just to the left of the pen tip)

marcusjb

I have seen them fail at that point multiple times and it is a pain in the bum fishing the nipple out.

I've seen it on older X600 and X700 shifters, so good to see shimano have solved that problem!

I have never suffered it myself, and try to change gear inner cables every 10000km.

Secteur

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19733991#p19733991]marcusjb[/url] wrote:

I have seen them fail at that point multiple times and it is a pain in the bum fishing the nipple out.

Yes - I had to partially disassemble the shifter to find the end which I knew was still stuck in there. Fortunately there is a clip on housing under the shifter which (once you work out that it is actually a removable housing) allows open access to the ratchet mechanism.


This is a part of my bike I never routinely inspected before, but all it takes is a quick flip of the rubber hood cover, and you can see any fraying immediately, so well worth doing every now and then.

mfin

Common problem this, certain Shimano shifters will eat the cable at this point until it snaps, happens on some of the 105 10 speed ones for sure.

veronese68

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19734125#p19734125]mfin[/url] wrote:

Common problem this, certain Shimano shifters will eat the cable at this point until it snaps, happens on some of the 105 10 speed ones for sure.

Must remember to check mine soon. Hopefully I haven't tempted fate in saying that.

crankycrank

I've heard it explained that it this case it's not so much friction or coarse surfaces of the cable routing but more the fact that when a cable has to move around a very tight bend it fatigues the cable and causes the fraying. Not always possible especially with the 6800 but the fewer the tight bends you can route your cables with the better.
Having said that make sure your cable housing is cut at a flush, 90 deg. angle and doesn't have any rough edges where it enters the shifter.

mfin

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19734476#p19734476]crankycrank[/url] wrote:

I've heard it explained that it this case it's not so much friction or coarse surfaces of the cable routing but more the fact that when a cable has to move around a very tight bend it fatigues the cable and causes the fraying. Not always possible especially with the 6800 but the fewer the tight bends you can route your cables with the better.
Having said that make sure your cable housing is cut at a flush, 90 deg. angle and doesn't have any rough edges where it enters the shifter.

No, this happens right at the shifter, not in the bends of cable after it exits. Besides a bend in your cabling that would be tight enough to 'fatigue' the cable would mean you'd never get your shifting to a usable state to start putting miles on the setup.

It's a design fault.

Your cable housing comment is a common sense one, but unrelated to this problem.

rozzer32

Yes I had this on my Ultra 6800. It happened on the Dura Ace 9000 too and they brought out 9001 shifters that apparently sort the issue out but people still have the problem.

Think it's just a case of inspecting and replacing cables every so often.

DrLex

FWIW, just found the same failure point on my Ultegra 6700 RD cable - about an inch from the nipple. Did take almost five years, though. More cursing expected when I attempt to rethread it later in the week.

keef66

My 10 speed 105 eats the rear shift cable every couple of years. In fact the shifting was less than perfect at the weekend so maybe it's time for another look. I think it's because of the tight radius when the cable is repeatedly fully wound round the mechanism in the shifter, and the subsequent straightening when it isn't. You can easily snap a wire coat hanger by repeated bending and straightening; I suspect the same apples to the individual strands in the twisted gear cable.

rolf_f

Veronese68 wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19734125#p19734125]mfin[/url] wrote:

Common problem this, certain Shimano shifters will eat the cable at this point until it snaps, happens on some of the 105 10 speed ones for sure.

Must remember to check mine soon. Hopefully I haven't tempted fate in saying that.

I recently commented on here about how my shifters had lasted for 30,000 miles without any maintenance bar a squirt of GT85. That very evening, on the way home from work, the right side paddle return spring broke. Just saying......