- Whilst the transmissions on most modern mountain bikes,
works incredibly well in a variety of conditions,
you still need to have smooth inner cables
for it to work properly.
Ideally, you wanna change your cables once a year,
perhaps more if you ride in really wet conditions.
So, here's how you replace your cables.
So, our tools for this job.
You need a four-millimeter Allen key or hex wrench,
a Phillips screwdriver, cable cutters,
Shimano inner cable, Shimano outer cable,
cable ferrules, cabling caps,
thin lube, and cable ties.
So first things first, let's remove
the old cables from the bike.
Ideally put your bike in a work stand.
If you haven't got one, get your friend to help you.
Then, you want to shift your chain
until it's in the smallest sprocket at the rear.
The reason for that is this is the position
with the least amount of cable tension.
This step is to remove the four-millimeter clamp
on the actual mech.
As you can see on Blake's bike here,
he hasn't got a cable end cap,
so you don't have to worry about snipping that off.
You wanna undo this,
and you wanna pull the cable away from the mech.
So with the cable released from
the rear mech end of the bike,
next step is to remove the whole inner cable
from the shifter.
There's a little cable port to cover
the Phillips screw head on that,
so you just need to remove that.
Pull the outer cable away, and then just gently
push the cable back through the shifter.
If you're doing a cable change halfway through the season,
you can often get away with keeping
the existing outer cabling in,
just flushing it through with lube,
and replacing the inner cable.
As you can see with the state of Blake's one,
he's got surface rust on it and all sorts of gunk.
So, we're gonna put a whole new system back in.
So our inner cable is out, time to
take the outer cable off the bike.
You gotta bear in mind on some bikes,
you're gonna have full external routing; sometimes you're
gonna have cable stops on the outside of the bike.
Some bikes you're gonna have full internal routing.
Or like Blake's got here, you're
gonna have like a variety of both.
So I'm gonna snip the cable ties on the chain stay,
and we're gonna keep this section of outer
so I can measure up the new piece I'm gonna put in place.
(electronic groove music)
If your bike has internal cable routing,
you need to consider this before you remove the outer cable.
If your bike has an outer cable length that
runs constantly all the way through
to the rear mech, don't remove it straightaway.
What you wanna do is get your new piece of outer cable,
attach it with a bit of tape to the old piece,
and you can use that to pull it through the frame.
There is another method for doing this.
You can have a dedicated internal cable routing tool.
But in this particular case, I don't need it.
On Blake's, it actually has a cable stop
at the front of the bike here.
If I just pull the cable out, then you'll see
it just has a single piece of outer that runs
to the frame, and the inner cable then runs
straight through the frame and out the BB shell.
So as you can see, the state of these outer cables
is pretty bad; they're quite corroded on the ends here.
So, just about cut these down to the same length
as the new sections we're gonna put in.
Make sure when you do this,
you only use a decent set of cable cutters.
This is something that a good cyclist should always own.
And when you do have a set,
don't use them for cutting anything else.
Don't be tempted to cut spokes
or anything 'cause you'll blunten these.
And the effect of that in the long term is
that when you go to cut an inner cable,
you'll just end up fraying it.
What I'll need to do with this is offer this
up against my new Shimano outer cable, and snip it.
An important thing to note when you cut the outer cable
is you can actually squash the cable slightly.
If this happens, it's gonna make it
a bit harder for the inner cable pass through it.
So make sure that you use these little jaws
on the inside of your set of cable cutters
just to make sure that it goes nice and round.
Even if you're replacing your outer cable
with brand new ones, like these Shimano units,
it's a good idea to give them a
flush through with some thin lube.
Although, if you do this near your bike,
make sure it goes nowhere near your brakes.
Now before you instal your inner cable into the shifter,
you just wanna give it a flush through with some thin lube
just to make sure that everything's good on the inside.
Note that I've got a rag here just
to catch any spray in case it goes near my brakes.
Cycle it through the gears a few times,
just to make sure the inside is running nice and smoothly.
And then finally, screw the barrel adjuster all the way in,
and then just come back a turn, just to make sure that
we've got a little room for error there.
Next up, simply feed the inner cable into the shifter.
Once you've located it, you can pull it through
from the barrel adjuster side.
And then just make sure the nipple
sits into its little holder there.
And then, finally, make sure that
you return the port cover screw.
That's just with the Philips screwdriver.
Now just make sure you can seal
the unit off and nothing bad can get inside there.
With the inner cable in place,
it's time to put the inner cable
into the outer and then get this into the bike.
Before you do that, it's a good idea
to take the ferrule off and feed
this onto the inner cable first.
Just makes it a bit easier.
What I need to do on Blake's particular bike here
is run the inner cable straight into the down tube.
The outer cable sits into the stop.
And I'll just need to pull the inner cable
out of the bottom bracket shell.
With the inner cable successfully routed
down through the down tube, now it's time
to connect the rest of the outer cable.
Make sure you follow your existing cable stops,
and trace that all the way through to the rear mech.
(electronic groove music)
Again, just making sure the outer cable
is following all the current stops
and the ones that it passed through before.
On Blake's bike, it's got four
little zip tie cable mounts here.
And I'm just gonna make sure that
these are all done up holding the cable in place.
And then I'm gonna insert the
outer cable into the mech itself.
With the outer cable successfully routed
all the way along the bike now,
secured in place with the cable ties,
all you need to do is clamp the inner cable at the mech.
To do that you wanna run the inner cable
into the mech itself through the stop,
and then just locate the outer cable in place here.
Okay, one of the last steps you need to do is,
just pull the inner cable through
and clamp it underneath this four-millimeter clamp bolt
that's got a little plate under it.
Now, you wanna pull it taut, but not too tight.
And it's important to not pull it tight;
otherwise you're gonna have problems
shifting down into the small sprocket.
You remember that you can take up the slack
with a barrel adjuster on the shifter after.
So, I'm just gonna pull this through and nip it up tight.
(electronic groove music)
With the inner cable secured,
you just wanna cut off the excess now.
You're not gonna need it to be too long.
And also you don't want it flapping around,
'cause it can get caught and fray.
Make sure that you cut it down,
and you fit one of these aluminium end caps.
'Cause they stop it fraying.
So the outer cabling is now reinstalled
on the bike, and the inner cable
runs all the way through to the rear mech.
It's now held in place with a pinch bolt,
and it's got a nice little end cap
crimped on the end to stop it fraying.
So your final step is just to make
sure that your gears are working.
So the final step of the indexing
is done up at the shifter end.
The shifter has got a barrel adjuster on it
and the job of the barrel adjuster
is just to take up the slack in the cable.
As I said to you before, when you
pull the inner cable through the whole system,
you don't wanna over tighten it.
The reason for that is you won't be
able to shift down into the smaller sprocket.
So you can always take that slack
back out using the barrel adjuster.
The other thing to say with the barrel adjuster is,
once you've got your gears set up and indexed perfectly,
after your first few rides, inner cables
do tend to stretch a little bit.
So you can wind it back out to compensate for that.
So what you're aiming for here is one click of the thumb
and the chain to jump up one sprocket.
If it doesn't go up the first time,
and you hear it just clicking on the next sprocket,
unwind your barrel adjuster of
the shifter until it does jump up.
Just get this pedalling slowly; one click.
And it actually jumps up well,
so I'm just gonna check it shifts back down again.
And it does successfully.
Now with indexing on Shimano gears,
you only really need to do it for three or four gears
to make sure it works for the whole
cassette 'cause they're evenly spaced.
A bit of a delay there, and there.
So, I'm just gonna unwind the barrel adjuster a tiny bit.
And now that seems to be working smoothly.
So that is it successfully done.
Inner and outer cable fitted to the bike.
Gears running nice and smoothly and ready for action.
If you wanna find out a bit more about
setting up and indexing your gears, click up here.
If you wanna know a bit more about
how to set your gears up and fix them
when you're out on the trail, click down here.
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