Gear cable jamming etc with duel type shifters

[Ajax Bay]

I've not had a gear cable break ever as far as I can remember and I had the first version of Shimano STI with my dura ace back in the early 90s. Maybe even the late 80s. I'd only be changing mine if I was replacing the group set. I don't change gear cables when I change bar tape either - am I a bad mechanic?

This 'fraying inside the STI' risk elevated when Shimano introduced the 'under bar(tape)' route for the gear cables, so very much this century. The main issue is the cable deterioration occurs out of sight and is a pita to extract once it breaks (likely in the middle of a ride with no warning).
Replacing gear cables on a schedule (time or distance) makes sense (and would entitle you to a 'good mechanic' badge).
I've only once had a gear cable break (and I coulda shoulda changed the cable before the ride as pre-travel I had seen a filament break at the FD clamp end). Was 70km into a 600. Used limit screw to fix the FD on the middle ring. Rode on to Rhayader (clivepowellbikes - great(known) bike shop) and replaced cable (and a coffee) and on north (17 minutes).

 

[cougie uk]

Ah. Most of my bikes of late have been SRAM. Never had an issue.

 

[C R]

I saw somewhere that shimano recommend changing gear cables every 2500 miles. I had a cable break at the brifter end at about 5500 miles, so now I am more careful with regular maintenance.

 

[Alex321]

I saw somewhere that shimano recommend changing gear cables every 2500 miles. I had a cable break at the brifter end at about 5500 miles, so now I am more careful with regular maintenance.

I've done 4,000+ on one set before now. In fact I haven't changed my front cable since I had this bike, and I've done just over 5,000 miles on it.

But I suspect internally routed cables may have a longer lifespan, as they aren't s exposed to weather/grit etc.

 

[Scottish Scrutineer]

I've done 4,000+ on one set before now. In fact I haven't changed my front cable since I had this bike, and I've done just over 5,000 miles on it.

But I suspect internally routed cables may have a longer lifespan, as they aren't s exposed to weather/grit etc.

The wear/failure point with the later Shimano shifters is inside the shifter body and the guide as it is bent to the internal pulley/ratchet. It makes no difference whether or not the cables are routed internal to the frame.

@Alex321, if i was you, I'd replace them promptly. 😊

 

[Alex321]

The wear/failure point with the later Shimano shifters is inside the shifter body and the guide as it is bent to the internal pulley/ratchet. It makes no difference whether or not the cables are routed internal to the frame.

@Alex321, if i was you, I'd replace them promptly. 😊

The front doesn't get used all that much anyhow, compared to the rear - which has been replaced, about 2,000 miles ago.

 

[Chislenko]

My personal policy would be to replace it if it snapped.

I think that is where the saying "Cure Not Prevention" comes from 😊

 

[T4tomo]

My personal policy would be to replace it if it snapped.

I think that is where the saying "Cure Not Prevention" comes from 😊

the only slight issue with that is, it has been known for the frayed strands of cable to fark/jam up the shifter mechanism, hence the saying "A stitch in time saves nine" or the lesser known "A new cable in time saves ten/eleven speed shifter"

 

[craigwend]

Just had mine replaced as fraying under bottom bracket cable guide after 6500 Miles. (SRAM Force)
Also had same with Shimano in the same place

 

[night cycler]

A bit more info.

Both bikes have Shimano 105 STI shifters.

The Triban 540 which has dropped bars came fitted with STI. The cable snapped at approx 3000 miles / 30 months riding. (Summer months).

The Rose bike had drops and STI shifters fitted 'after market'. The cable snapped at approx 1900 miles / 18 months riding (winter months).

The wet weather riding possibly contributed to the cable on the winter bike failing sooner.

 

[RRCC]

I have 5700 shifters and have had to change the rear derailleur cable about every 5000 km when they have started fraying in the shifter and making changes, particularly down changes, slower and less precise.
Change for Jag wireless sealed systems which at least mean you can change the cable without silliness with the internal routing.

 

[Alex321]

I have 5700 shifters and have had to change the rear derailleur cable about every 5000 km when they have started fraying in the shifter and making changes, particularly down changes, slower and less precise.
Change for Jag wireless sealed systems which at least mean you can change the cable without silliness with the internal routing.

What "silliness" might that be?

I don't know if it is true of all bikes with internal routing, but with mine (Cube Attain GTC), you just thread the cable straight through. I haven't done it myself, but I watched Simon from Simon's cycles in Cowbridge do it, and there was no silliness involved at all.

 

[Ajax Bay]

I haven't done it myself, but I watched [someone] do it

Love to hear assertions of objective confidence. Were you feared to do it yourself, then? See also Marathon Plus tyres.

 

[Alex321]

Love to hear assertions of objective confidence. Were you feared to do it yourself, then? See also Marathon Plus tyres.

No, I wouldn't have been feared to do it myself, but the old cable had got caught up in the shifter, and I couldn't work out how to free it, so I called in there to see if he had any ideas.

Took him a few minutes to get the old one out of the shifter, but only took a few seconds to feed the new one through the sleeve, which I presume from how quick and easy it went through, must go all the way through the frame.

Not sure what you mean by "see also marathon plus tyres"? I've had those in the past, and they could be hard to get on, but I always did it.

 

[Mr Celine]

Happens regularly to the rear cable on my bike, 5600 Shimano 105.

This has a triple chainset, so by adjusting the limit screw on the rear mech to keep the chain in the middle of the cassette I can always ride home as a three speed.
I change the cables every two years (about 4000 miles) if they haven't broken sooner.