sweeks

This is "cyclic fatigue"... one of the banes of my life as an endodontist. I'll pitch a $20 instrument after one use rather than have it break off in a root canal.
But... back to the shifter. I have a 22-year-old bike with Ultegra 3x9 on it that has never had a cable fray. To be fair, the bike only had about 8,000 miles* on it when I changed to trekking bars recently, but the cables were completely intact. Is it possible that the OP's particular shifter has a stress riser of some sort inside the mechanism; a rough edge or something? I would be pretty unhappy with having to change the cable every 1,000 miles even though on average that's every few years for this bike.
*A lot of those were in southern Wisconsin, so plenty of shifting was going on.

FBinNY 

Too many variables to form any kind of opinion. Also the time lag between the start of fraying to failure can be very short.

I strongly doubt that it's anything specific to the OP's lever. The large number of people reporting the same is very convincing evidence of the problem being inherent in the system.

Lombard

Your shifters are older and have the shifter cables coming sideways out of the shifters, correct? The problem did not exist until the Shimano generation where the cables run under the bar tape.

grumpus

Carry a few inches of cable with the nipple attached, then when you need to bodge it to get home you can thread the cable through the rear mech to hold it in one of the lower ratios.

sweeks

My shift cables were under the bar tape. Apparently I've just been lucky.

EDIT: Hmmm... maybe you're right... it was the brake cables that were under the bar tape.

Lombard

Hmmm. I didn't think Shimano had any cables under the bar tape until the 5700/6700/7900 generation which was 10-speed.

I have a bike that has 5600 and the cables are external.

sweeks

To be fair, we'd also have to know how many people *didn't* have this problem to have a proper handle on its prevalence.

FBinNY 

+1 On tours or long day rides I carry a 2" brad, or direct pull spoke with the 5mm hex key that's the main part of my road tool kit. I set the RD for my favorite cruising gear, and ride 2s to get home. If there's a longish climb, I'll get off and "shift", then shift back at the top.

FBinNY 

In your line of work, do you think about all the teeth that are OK, or do you focus on those needing root canals?

Likewise, we have large numbers of this kind of cable failure. I know how and why they fail and don't think about the cables that don't. For all I know, those bikes simply haven't been ridden far enough yet.

Lombard

There is clearly a problem with these shifters. We don't know why some people put many miles on these shifters without a problem. That would lead to a QC issue although there is clearly a design flaw as well.

yannisg

My Cannodale synapse has Ultegra R8000 shifters.
I have this bike for 9 yrs. Since its not my only bike I estimate 10000k on it.
I'm still using the original cable housings and wires.
However, I very rarely ride in wet conditions, but ride a lot of hills therefore a lot of shifting.
Recently, my left shifter jammed because of dirt in the mechanism. However, the wire was not frayed and looked ok.
Decide to replaced cable housing and wires at this point.

SpedFast

Yeah, like you, I have a bike that is only ridden in fair weather with the internal cable routing on 105's. It has close to or over 10k Miles on it and is still using original cables and housings with zero wear showing. I keep it lubed and use it on the trainer in the winter. Even on the trainer I shift a lot (OCD maybe) My vintage bike with fenders gets all the abuse and foul weather and I have to change cables on it every other year and it's lucky to see 3K miles between cable changing with stem shifters. I have switched to stainless cables so maybe they won't rust so fast. Salt air is bad on everything. I do clean it after every ride and oil alot but it feels like a losing battle against the elements.

smd4

When are they going to invent something to replace stainless steel wire cables? Something that won't fatigue. Like carbon fiber cables or something?

FBinNY 

Already did. Something like 20 years ago someone marketed Kevlar cables and they had some success for a short while

However, it's very possible for makers improve cable life. The biggest improvement would be to increase the cam's radius. And/or It shouldn't be difficult to improve cable suppleness.

The goal should be to get the cam's and wire's free bend radii more closely matched.

Alternately, the overall design could be modified to avoid winding the wire around the cam, and having the pull in a straight line, as do brake cables.

One other possible consideration may be rider habits. Aggressive, crisp shifting may be harder on the cable. The higher peak tension during the bend may increase strain and shorten fatigue life. I offer this only as something to think about. It would take some practical experiments to move this from conjecture to theory or proven fact.

Anyone curious can do a simple experiment with the scrap end next time they replace a cable. Bend it over your thumb or finger. If it springs back straight, it won't fatigue in use. If it takes a set, the tighter the set, the shorter the expected life.

Lombard

The front shifter cable won't wear anywhere near as fast as the rear shifter cable. Not only do you use the front shifter a lot less, but it only moves between two gears, not 11.

SoSmellyAir

Electronic shifting has been invented for a few years now.

sweeks

I wasn't trying to be adversarial. My point was that these reports of cable failure are not a random sampling of the shift cable population. Nobody reports the cables that don't fail, which can lead to an impression that there are more failures than there actually are.
I don't doubt that you have seen many more of these problems than I have, or ever will. But, as you like to say, give me a little credit: I'm not saying that because I haven't *personally* had this problem that it doesn't exist.

SoSmellyAir

Shimano released Ultegra R8000 in 2017. 100 PRODUCTS HISTORY - SHIMANO ULTEGRA | SHIMANO That was less than 7 years ago. But still an impressive duration for a bike which is ridden regularly over this period.

smd4

Hard pass.

I have automatic watches, fountain pens, fire a steam locomotive and use cables on my bike. I’ll be riding and telling time long after your crap has died.

SoSmellyAir

I don't have electronic shifting on my bike; I do have it in my car. I also have automatic watches and fountain pens. Being a parent, I am sick of Thomas the Tank Engine and his colleagues, but I do want to marvel at how you added networking capability to your typewriter in order to post here on BF.

FBinNY 

Didn't think you were, nor was I.

It's not about how common a problem is, it's about understanding causation and process by which these failures occur.

The mechanism is well understood beyond the bike industry. It's common to all cable systems, and there are a number of engineering specs written around it, covering things like miminum pulley diameters and elevator cable replacement schedules.

Lombard

Ahhhhh, the solution to a design flaw. Eliminate the product and come out with something way more expensive rather than fixing the design flaw.

SoSmellyAir

As alluded to above (and expressly noted in other threads regarding the RD cable fraying within the shifter), the issue arises from the cable traveling through a relatively right bend within the shifter body so that it exits largely parallel to the longitudinal axis of the shifter body, to allow the cable housing to be hidden under the bar tape and/or partially within the handlebar. This is a departure from the previous (Flight Deck?) models in which the cable exits in a perpendicular direction from the side of the shifter body. So, it seems to be a design limitation rather than a design flaw -- but regardless of which -- due to a design choice adopted by every manufacturer.

Lombard

If this is a design limitation and not a design flaw, how is it that SRAM manages to make a shifter with under bar tape routing and they don't eat through cables like Shimano shifters do?