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Fresh gear cables can make your shifting feel like new

One of the problems with using metal cables to control bicycle transmissions is that the  weather does its best to ruin them, with water to cause rust and dirt to gum everything up. If well looked after, gear cables can last years but if you leave them to the weather, you could be fitting replacements often, which isn't cheap. If corrosion has got the better of one of your gear cables, here's how to replace it.

Our guide below shows you what we believe is the best method to refit a gear cable in a SRAM Rival hydraulic road brake/gear lever. We've included a list of the tools and materials that you will need to complete the job and in some cases where you can buy them. If there are others that you prefer then feel free to let everybody know in the comments.

Tools & Materials

How to replace a gear cable 15

New cable

Cable cutters

Allen keys

Fitting a new gear cable should be pretty simple, but modern bikes with internal routing and convoluted cable runs through the components and frame can make what used to be a five minute job take a bit longer. For example, frames with internally routed cables can require removal of the cranks and bottom bracket as is the case with the bike in our example below.

Be methodical and don't be afraid to to take the long route. Some of the fuzzy logic used by the component manufacturers means some of the simple steps, like threading the new inner cable through the shifter mechanism, is a pain unless you take the shifter off the bars. So, deep breath and let's fit this new rear gear cable.

 

How to replace a gear cable 01

1 Unfasten the old cable Fully down shift the rear gears. Undo the rear derailleur cable anchor bolt. Unthread the inner cable from the grooves and guides that are on the rear and underside of the rear derailleur.  

 

How to replace a gear cable 02

2 Pull out the cable Pull the inner cable out through the derailleur's barrel adjuster. If there's a protective cap crimped on to the end of the cable, a good tug at this point will pull it off.

 

undo-brake-strap-bolt

 3 Remove the lever Unwrap the tape from the right hand side of the bar. Roll the rubber lever hoods forwards as shown here and use a 5mm Allen key to loosen the retaining bolt which holds the brake lever to the bar.

 

How to replace a gear cable 08

4 Slide the lever off of the handlebar We do this because it is extremely difficult to thread the new inner cable through the shifter with it on the bar, a design failing of the SRAM Hydro R brake/shifter unit. I haven't quite fully removed the old inner cable here, you can do it before or after lever removal, it doesn't matter which.

 

How to replace a gear cable 05

5 Select the nipple Most new gear inner cables have nipples on both ends. One end is a cylinder with squared off ends (the top one in this shot), the other end is a shorter cylinder with domed ends. For Shimano and SRAM shifters we need the squared off end; the other fits Campagnolo shifters, because having the same fitting for such a common spare would be too simple. Trim the other end off. 

 

How to replace a gear cable 06

6 Cut off the 'wrong' nipple Use the sharpest cable snips you can find. These are Park Tool CN10C Pro cutters and are the benchmark. They're ideal for trimming inner and outer cable and have shaped areas (visible below the pivot bolt at the bottom of the shot) that are great for reforming cable outer for a tidy finish.

 

How to replace a gear cable 07

7 Feed in the new cable With the fresh cable cut, you can feed the end into the hole in the lower inside edge of the plastic lever housing (see the bottom of the shot). It goes into a red plastic piece and up and around the ratchet mechanism, exiting the lever body through a hole in its top outside edge. There is a slot (just visible to the right of the top piece of cable) which leads to the channel into which the outer housing for the bars meets the shifter. 

 

How to replace a gear cable 04

8 ​Pull the new cable through Make sure that when you reach the last bit of inner cable, that the nipple goes cleanly into the hole in the shifter body and sits fully into its seat. Without kinking the cable, give the end handing out of the shifter top, a tug just to be sure.

 

grease-inner-cable-2

9 Lube the cable Grease the section of inner cable that will be  under the bar tape. There are some sharp turns to make it from the shifter and around the first bend of the bar, so the grease will help mitigate the friction. 

 

How to replace a gear cable 09

10 Replace the lever Refit the brake lever on to the bar, ensuring it's at the right height and angle. Bolt it down with the 5mm Allen key. With the run of housing ready, thread the greased inner cable through the outer.  Push the outer ferrule fully home into its hole in the shifter body. Tape the gear and brake lines to the bar. 

 

How to replace a gear cable 10

11 Thread the cable Depending on your frame you might have external cables, in which case just thread your fresh inner cable back through the stops and housing runs to the rear derailleur. Internal routing technique will vary by brand and model. This Turner Cyclosis frame uses removable panels (the black oval). In this case we just need to thread the end of the inner cable into the cable stop and through the tiny hole in its base. This will allow the inner cable to enter the down tube. 

 

How to replace a gear cable 11

12 Route the cable through the frame Remove the bolt which retains the plastic cable guide. again frames very on how the guide is accessed, Many, like this Turner, use a simple hole in the bottom bracket shell to allow access for a long 4mm Allen key.

 

How to replace a gear cable 11

13 Push the inner cable fully into the downtube You'll need to poke your fingers into the bottom bracket shell and into the bottom of the downtube.  There will most likely be a step edge stopping the inner cable from just poking into the BB shell. Feel around for the cable end and coax it through.

 

How to replace a gear cable 12

14 Thread the new inner cable through the appropriate slot in the guide, its usually the one on the right hand side (left in this picture), the centre slot is for the front derailleur cable, but as this bike is a 1x set up, there is no cable. Now the tricky bit: Pull the cable through and as you do slide the guide back up the cable and work it back inside the bottom bracket shell and into its normal position. As you do this you also need to slot the end of the inner cable up the inside of the right hand chainstay.  Secure the guide with the 4mm Allen key. It takes patience of a saint and the fingers of a child to manage it cleanly. Worry not, even the best mechanics find this tricky.

 

How to replace a gear cable 14

15 Thread the cable through the stay The end of the inner cable is inside the chainstay. On this bike the black panel unscrews and you can pick the end out. Thread the black housing on to the cable and re-screw the housing back into the chainstay. At this point we often pull the cable tight with our left hand and operate the shifter with our right, just to check the inner cable is running smoothly. 

 

How to replace a gear cable 03

16 Fit the last piece of outer Thread the last piece of outer housing onto the inner cable and ensure that the ferrule is seated into the stop in the chainstay. 

 

How to replace a gear cable 17

17 Fit the cable into the derailleur Pop the end of the inner cable through the rear derailleur's barrel adjuster. This is actually quite a skill. Take care not to damage the end of the cable and cause an ugly fray. If it does, you should have enough spare cable to make a trim and go again. 

 

How to replace a gear cable 17

18 Tighten the cable clamp Route the cable inner through the grooves and guides of the rear derailleur into the clamp. Pull the cable so that it is tight, but not so that it pulls the derailleur's parallelogram, then tighten the clamp bolt. You now need to check the indexing of the rear derailleur.

​>> Read more: The full archive of road.cc maintenance articles

 

13 comments

Avatar
bendertherobot [1541 posts] 3 years ago
3 likes

SRAM version.

Unthread old cable.

Get lever into correct position so that hole is visible.

Cut new cable with NASA level laser

Ensure end of cable bonded with nano particles

Grease cable with slickest substance known to alien kind

Insert cable

Wiggle

Stop

Have a vodka

Try again

Kick cat

Pray to your God

Achieve movement

Promise never to do it again

Avatar
Chris James [449 posts] 3 years ago
2 likes

What a faff. I'm glad I have Shimano shifters and external cabling. It makes changing cables a piece of cake.

Avatar
tritecommentbot [2266 posts] 3 years ago
0 likes

I had to change both brake and gear cables this week after getting new shifters and selling the old ones on. Thought it was going to be hell because of the internal routing and the fact that I've got no clue what I'm doing at all.

 

Was surprisingly simple! Frame has bits you can either unplug or unscrew to help guide the cable. No need to take cranks or bottom bracket off or anything like that, it's all cleverly designed (Infinito CV frame, but I'm guessing most modern frames now are designed similarly?).

 

The end of the bike shop for me.. nearly. Pretty much rebuilt the whole bike this week except the cranks which was done a week previously and the only thing that's tricky is getting the front derailleur and rear derailleur indexed/set up.

 

Still haven't got the hang of that, will have another shot later today but reckon I may need to suck it up and get a bit of help.

Avatar
LastBoyScout [621 posts] 3 years ago
0 likes

Section 5: The domed, Campag end will fit Shimano and SRAM as well as Campag, but the Shimano/SRAM end can catch inside a Campag shifter.

I have Shimano and Campag and just use use the Campag ones on everything - apparently, that's what my local bike shop does.

Avatar
Welsh boy [679 posts] 3 years ago
0 likes

Why do you say "Fully down shift the rear gears" when you clearly mean shift UP?

If you change down a gear you go onto a bigger sprocket.  A fairly basic concept and not too difficult.  Stupid mistakes like that make it difficult to take any of the article seriously.

Avatar
bendertherobot [1541 posts] 3 years ago
0 likes
Welsh boy wrote:

Why do you say "Fully down shift the rear gears" when you clearly mean shift UP?

If you change down a gear you go onto a bigger sprocket.  A fairly basic concept and not too difficult.  Stupid mistakes like that make it difficult to take any of the article seriously.

 

Down the cog. It might be contrary to what we understand by the terms but I'm sure that many use that phrase in this context.

Avatar
Dr_Lex [502 posts] 3 years ago
0 likes

If you've an internally-cabled bike, get some thin sleeving to use at step 2. Once the cable is released from the rear derailleur and the outer sleeve removed, put a length of this over the cable and slide into the frame. (You may need two pieces, one either side of the bottom bracket guide). This saves an awful lot of time fishing for the cable & swearing. You may, of course, still hit the vodka as per Bendertherobot's list. There's some good YouTube videos to watch that show this - https://m.youtube.com/watch?v=gQU5BNpnohU is one.

Oh, and if you're changing the gear cable on the LH ultegra 6700 (front mech.), do not take off any hatches from the side of the hood, as if changing that on the RH one. I now need a new shifter... 

Avatar
cyclisto [412 posts] 3 years ago
0 likes
LastBoyScout wrote:

Section 5: The domed, Campag end will fit Shimano and SRAM as well as Campag, but the Shimano/SRAM end can catch inside a Campag shifter.

I have Shimano and Campag and just use use the Campag ones on everything - apparently, that's what my local bike shop does.

 

Same for my LBS who gave me domed cables (for brakes not gears) and they told me that they are for Campy but they will be just fine for Shimano too. So far they work good.

Avatar
TypeVertigo [429 posts] 3 years ago
1 like
Welsh boy wrote:

Why do you say "Fully down shift the rear gears" when you clearly mean shift UP?

If you change down a gear you go onto a bigger sprocket.  A fairly basic concept and not too difficult.  Stupid mistakes like that make it difficult to take any of the article seriously.

The "stupid mistake" is referring to the direction of the chain's actual travel along the cassette.

Shifting DOWN is from a larger to a smaller cog.

Shifting UP is from a smaller to a larger cog.

You'll be surprised just how many people refer to shifts this way. It's not the same as shifting on a car.

Avatar
thereandbackagain [173 posts] 3 years ago
0 likes

"6 Cut off the 'wrong' nipple "

And this is where things have gone wrong.

It's no problem at all to thread a new inner through SRAM (or Shimano & Campag) shifters if you use a single-ended cable where the bare end has the strands welded together. There's no danger of the strands coming loose and causing issues.

Also, you can sometimes use part of the old cable to pull the new one through the frame, if you can find a length of thin plastic tube that just slips over the inner.

Cut the original inner at a convenient external point, and then either slide the plastic tube over the old inner until it pops out of the frame, or withdraw the inner with the outer attached (depends on how tight the temp outer is over the inner i.e. will it come loose) until the same thing happens. Then, insert your new cable into this temporary guide  until it makes its way through the frame, then remove the temporary guide.

It's always worth replacing the outer cable section that feeds into the rear mech when you do the inner, as that's the one most likely to get contaminated with road dirt and cause shifting issues.

 

 

 

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urbane [100 posts] 3 years ago
0 likes

I use Finish Line Teflon grease on the whole length of my cables to stop water/dirt damaging the cable or locking the cables in freezing weather. 

All that road bike faff makes me glad I have Shimano MTB parts with much less cable stressing.  My new Deore Hollowtech groupset looks even kinder to cables, because the front mech supports the cable like a pulley and the Shadow type rear mech needs little bend of the cable cover and no stupid distorting movement of it when changing gears.

I'm not impressed by anything SRAM except some old adjustable V-brake levers I have, I think KMC make better chains than both Shimano and SRAM.

Avatar
ch [188 posts] 3 years ago
0 likes

And lets not neglect to change it just before the old cable breaks.

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oldmixte [118 posts] 3 years ago
0 likes

With an alloy frame use a strong magnet to catch the cable, one from an old disk drive is usually good enough, even then it can take hours, at least it did on my Cannondale Synapse. What a stupid design! There’s no way you could do this on the side of the road unless you were very talented or a magician.