Gear cable fraying inside Shimano shifter

[Ajax Bay]

I am running Tiagra 4600 shifters with the washing lines and they are worse for fraying cables than the Ultegra with the hidden cables they replaced.

This is not my experience with over 50k on Tiagra 'washing line' STIs (so with @Tenacious Sloth here in 'surprise' mode). A fair few cable changes and no fraying discovered on removal as part of planned maintenance (several times they're then used for the front derailleur cable which experiences less use/fatigue cycles). So I think your assertion is not on sound foundations. Have you a source?
Physically the cable is subject to more tight turns when delivering the 'under bar tape' route and there seems a reasonable physical basis for that to cause earlier fatigue and breakage.
Anyway if they're worse than the Ultegra you had why are you using the ST-4600s?

 

[iluvmybike]

It's not the running under the bar tape that causes the problem - it is the tight turns at the ratchet - they always fray just where the cable exits the ratchet

 

[Bike Tyson]

This is not my experience with over 50k on Tiagra 'washing line' STIs (so with @Tenacious Sloth here in 'surprise' mode). A fair few cable changes and no fraying discovered on removal as part of planned maintenance (several times they're then used for the front derailleur cable which experiences less use/fatigue cycles). So I think your assertion is not on sound foundations. Have you a source?
Physically the cable is subject to more tight turns when delivering the 'under bar tape' route and there seems a reasonable physical basis for that to cause earlier fatigue and breakage.
Anyway if they're worse than the Ultegra you had why are you using the ST-4600s?

I changed to the Tiagra shifters when my Ultegra shifters broke, was on my second set of thoses and I thought the Tiagra ones would be fine( Cheaper) but like I say keep needing to replace frayed right hand gear cables, I have a set of 105 10 speed shifters now spare from my old winter bike that I dismantled so will probably put them on and keep the Tiagra one for spares.

 

[Tenacious Sloth]

It's not the running under the bar tape that causes the problem - it is the tight turns at the ratchet - they always fray just where the cable exits the ratchet

Yes. But my point was that the cable wouldn’t have to make such a tight turn if it wasn’t routed under the bar tape.

 

[faster]

Yes. But my point was that the cable wouldn’t have to make such a tight turn if it wasn’t routed under the bar tape.

Whilst there are undeniably more turns to route the cable under bar tape, it doesn't make any of the turns any tighter.

The tightest turn is, I think, always the one where the cable wraps around the pulley in the lever, and it's here where cables tend to break.

IMO, cables being under the tape has nothing to do them fraying. I think it is to do with the 'sweep' of the lever when changing gear, a longer throw equating to having to wrap around a smaller pulley in the lever.

My experience is similar to that of Bike Tyson. I had a set of Sora 3400 washing line levers (which required a really long sweep to shift) where it was difficult to get 3k miles out of an inner (worse than Ultegra). Sora 3500, which are also washing line, require a much shorter sweep to shift and have much better cable life.

 

[simongt]

I seem to recall a firm that did Teflon inner coated brake & gear cable sleeves, the idea being that the cables wouldn't stick. Trouble was that they eventually realised when customers began complaining, that the Teflon was wearing away, breaking off in tiny, tiny pieces and causing the cables to gum up even more - !

 

[Ajax Bay]

@faster @Bike Tyson interesting. I had ingested the general wisdom that the cable parting right up in the STI only became a 'known' fail point with the advent of the under bar tape varieties of STI. But maybe the blame is falsely laid? Were people reporting this 15 years ago?

 

[Bike Tyson]

@faster @Bike Tyson interesting. I had ingested the general wisdom that the cable parting right up in the STI only became a 'known' fail point with the advent of the under bar tape varieties of STI. But maybe the blame is falsely laid? Were people reporting this 15 years ago?

Well if you think about it there is no real difference if the gear inner is under the bar tape or washing line style, the cable is basically sitting straight in the shifter when in the smallest cog in both types of shifter, The fraying usually occurs in the first few inches anyway.

 

[Ajax Bay]

Think the issue is when the cable parts within a centimetre of the end, frays and prevents spring release, and therefore makes removal a pita. Why would a cable fray two inches away from its end? I asked you if you had a 'source' for the 'washing line STIs fray more' assertion: I assume you couldn't find one? Anecdata? When you think of the millions of STIs out there you'd think this was documented as a failure mechanism.

 

[Bike Tyson]

Think the issue is when the cable parts within a centimetre of the end, frays and prevents spring release, and therefore makes removal a pita. Why would a cable fray two inches away from its end? I asked you if you had a 'source' for the 'washing line STIs fray more' assertion: I assume you couldn't find one? Anecdata? When you think of the millions of STIs out there you'd think this was documented as a failure mechanism.

The last time I looked at a ruler a centimetre was less than two inches, my point was the cable frays inside the shifter and has nothing to do with the route out, of course it is anecdotal, I am not making a statement of fact, I thought I was just sharing my experience.

 

[Jenkins]

Is the cable run on a Shimano shifter tighter than on a SRAM one? I've three bikes with Rival or Apex where I've not had to touch the cables, but one with 105 where the cable frayed in the shifter and had to be replaced and this was the newest of the four.

 

[Mr Celine]

The cables in my 5600 10 speed 105 shifters regularly broke, usually in the middle of nowhere.
I now replace them regularly and fit the old cable to my flat bar bike, which doesn't have the issue with the tight turn over the ratchet.

If the under bar tape cable route was the cause the same problem would occur with brake cables. It doesn't, at least IME.

 

[Tenacious Sloth]

If the under bar tape cable route was the cause the same problem would occur with brake cables. It doesn't, at least IME.

Not really, as brake cables have an almost straight run from the bar tape.

 

[T4tomo]

I rode LEJOG in 2018 with a single front chainring and a bar end shifter ... great ride ... When we arrived at JOG campsite I carefully removed the bar end shifter...
AND FLUNG IT INTO THE FECING SEA !!!!!
Never again ...

Whilst they aren't quite as accessible as integrated brake and gear levers, I have 2 bikes with bar cons, 1 vintage suntour friction ones and 1 "modern" microshift indexed 1x10. I really like them. I might have root around JOG if I'm ever up there! they are much preferable / to hand to than downtube shifters.

 

[Mr Celine]

I think this was the last time, July 2019.

Note the upward pointing rear shifter cable and the corresponding hole it came out of. The straight cable route into the shifter is of no benefit, it is the tight bend inside the shifter that causes the fraying and breakages.

This bike is a triple, so a few tweaks on the limit screws and it's rideable as a 3-speed.