SoSmellyAir

The rear derailleur cable in my bike snapped this past Wednesday during a ride, leaving the chain on the smallest rear cog and me needing a ride home. My diagnosis revealed that the cable was severely frayed and snapped inside the right STI lever, a big PITA to remove. There are about 2,300 recorded miles on this bike, and another maybe 500 to 700 miles before I started using Strava and/or Wahoo apps to track my mileage. This failure seems kind of premature? I know many of you ride much higher mileage (but maybe shift less often) than I do; how often / frequently do you folks change your derailleur cables?

I have bought both derailleur and brake cable kits and am working on replacing them all. Luckily the cable routing in my bike does not look too convoluted.

base2 

Yep. Your resulta are about on par with expectations. 3-5000 miles for a right shifter is pretty common depending on how often you shift. I've never worn a left (front) shift cable. I'd venture 10k plus but, you never know. YMMV.

Why didn't you use a tool from your fix-it kit & drive the "H" screw all the way in to a better cog? I'm sure the 14, 15, or 16 cog would've been nicer than the 11 all the way at the bottom.

cxwrench

How long is a piece of string?

(Kerry Irons quote)

SoSmellyAir

Thanks. Makes total sense that the RD cable would be the first of the four to wear out on a rim brake bike. I probably shifted too frequently in the past, especially since last fall (just before I joined Bike Forums), I bought an 11 speed close ratio 12-25 cassette, which lets me finetune my cadence to my heart's content. But recently I am getting a bit stronger and can pedal within a slightly wider cadence range. So from now on I will replace the cable before I hit 3,000 miles just to avoid having to dig out a frayed derailleur cable from the STI lever.

That is a good idea, but I don't carry any tools or spare parts. My rides are generally 25 to 35 miles long and within about half an hour's drive home, so I would call my wife, Uber XL, or just walk home if I am really close.

SoSmellyAir

Ahh ...

expected life of components? | Road Bike, Cycling Forums (roadbikereview.com)

TiHabanero

A friend of mine has 5 years and 12,000 miles on his thus far. Not sure brand and model make a difference. He is using Sram Red 11 speed. Original cable.
My road bike has 3 years and 5500 miles. Campy Record 11 speed. Original cable.
Raleigh Professional, 1979. Well over 20,000 miles. Campagnolo Nuovo Record down tube shifters. Original cable.

rm -rf

Are the cables routed inside the frame? That requires a different technique for cable replacement. Don't just pull out the old cable! There's usually no guide or tube inside the frame. See my old post for an example.


Front derailleur cables seem to last "forever", I usually just change the rear cable. Brake cables don't wear out either, I wouldn't replace them unless there was wear in the housing causing the brake pull to feel rough.
The LBS should be able to sell you inexpensive generic loose shifter cable instead of the housing + cable kit. I'd replace the housing every other time.

There should a window to see the shifter cable inside the shifter where it takes the bend, just fold back the hood and see. Regularly looking for broken strands is a good idea after around 2000 miles.

JohnDThompson 

I see derailleur cables fail most often at the cable anchor, especially on low-end derailleurs using an eye-bolt, which if over-tightened tends to cut cable strands, and, less commonly at the shift lever. When this happens can be quite variable. I have some derailleur cables that are several decades old and still going strong.

andrewclaus

You may have noticed a few weeks prior to the break that you needed to turn the barrel adjuster to keep accurate shifting. Next time that will be your clue.

The easiest way to check it is to shift into low gear, stop pedaling, shift into high so you have a loose cable, and push the cable end out of the shifter. I do that every few thousand miles.

HillRider

Current Shimano STI's that run the housing under the bar tape have a reputation for fraying the cables right at the shifter so your experience is not uncommon. Older style Shimano brifters with exterior cables and other like Campy are easier on cables. I have Gevenalle "Retroshifters" on my bikes (basically downtube levers mounted on brake hoods) and those shift cables seem to last forever.

However, shift frequency is certainly a factor in any discussion of cable life. Shift more, the cable dies sooner.

dedhed

Take the loose cable and pull it into a useable gear and tie it off on the frame/bottle cage where ever you can.
Or find a stick or whatever road side of a size that works and wedge it into the derailleur parallelogram so it sits in a useable gear.

SoSmellyAir

Thank you! Your old post is very helpful. The cables for my bike are internally routed, but without the thin internal tubing shown in your old post. Your suggestion to run thin internal tubing over an existing cable before removing the latter and leaving the former as a guide for a new cable is brilliant. Where can I buy such thin internal tubing (preferably for both brake and derailleur cables)?

I had to remove the right shifter from the handlebar to extract the severely frayed top end of the RD cable, and the fraying has probably damaged the interior of the housing as well. So since I already bought both kits I will replace all cables this time. I will check under the right shifter hood regularly from now on and replace only the RD cable at the fist sign of fraying.

SoSmellyAir

You are right! In my inexperience I had [incorrectly] assumed that the need to fiddle with the barrel adjuster was due to excess wax on a freshly waxed chain.

This sounds easy enough. Thank you!

deacon mark

I have done the same thing and my Ti has exposed cables. I ride year around but in the winter they tend to go bad faster. Right now I have over 4000 miles on my rear cable since the change in June 14th. I have been riding huge miles and really so far so good. At any point you start to feel the shifter being a bit sticky or require even a slight more attention in the shifting then check it out and put on a new cable. A new cable is cheap. For me too the rear loop is the first to go. I upgrade and bought the Shimano premade rear loops they use for ultegra, I also have Shimano 6800 mechanical but I did upgrade the rear derailleur to 8000 because I like the angle better for the pinch bolt clamp and shifting is smooth but so was the 6800 derailleur it is spare now.

In the end a new cable put in is a no brainer. Worth the $4 bucks I use Jagwire or shimano die drawn, it like why mess around on something easy to keep working and not expensive.

bikemike73 

All great advice and knowledge !!!!!

Thank you all for sharing. I hope this never happens to me, or anyone else..

But if it does...it's good to know what to do

Safe riding !!!!

zacster

I've put at least 10000 miles on my last set of cables and they are fine. I'm running Chorus 10 and used Campy cables.

woodcraft

Shimano shifters are hard on cables. Replacing the rear shift cable once a year is a common practice to avoid the hassle you just went through.

sweeks

I have to say this has not been my experience. I have an old mountain bike (Trek 6000, bought in 2000) with about 6,000 miles, and a low-end Shimano drivetrain. I have an old road bike (Airborne Carpe Diem, bought in 2001) with about 8,000 miles, and an Ultegra 3 x 9 drivetrain. My current commuter bike (Tern Verge S11i) has an Alfine 11 with a trigger-shift and 10,000 miles on it.
None of these bikes' original shift cables has given any trouble. I must be lucky!

himespau 

https://www.ebay.com/itm/123735774909 is what I would use.

woodcraft

My comment only applies to brifters with concealed cable housings- they have a tight bend right by the lever,

& as the OP states, it's hard to get the broken end out- still, inspecting them once in a while is not a bad idea.

sweeks

That's cool. My bike with Ultegra apparently defies the odds, but as I said, I may have been lucky.

SoSmellyAir

Pre-pandemic, Uber XL would be no brainer, but I did not have a mask with me last time. I will put one in my jersey pocket from now on; I can retroactively justify switching from football to bike jerseys.

Pratt

Funny you should mention that. Just this Summer, My front derailleur cable broke. Just to be sure, I replaced both front and rear. The rear had a couple of broken wires, up near the shifter end. The bike is a Bruce Gordon that I bought in about 1992. I thought it odd that the front, which gets shifted much, much less than the rear, broke first.

Litespud

I replace the RD cable (Campag Chorus 10sp shifter) about every year. I ride ~6k/yr and I do a lot of shifting as a result of a close-ratio cassette. The cable lets me know when it's time by poking me with a couple of frayed strands protruding out from under the shifter hood. I have a Jagwire cable set, and I can get individual Jagwire inner cables from the LBS. Some setups tend to eat cables, but ~3000 miles seems a little voracious indeed. Next time you have the system apart, make sure that the housing ends are clean and there are no burrs or edges. Don't forget to grease the inner cable, especially where it enters the housing at the shifter.

SoSmellyAir

I have to grease the cable at the housing? I thought buying the fancy $$$ Dura Ace polymer coated cable and housing kit means I can avoid doing so. Would lithium grease do or do I need to buy another type of grease?