How To Adjust Your Front Derailleur

Do you have to listen to this noise when
you ride? Does your chain come off when

you try and shift into the big ring?
If so, you need to adjust your front

derailleur, which fortunately, is,
actually, a really simple thing to do.

All you need is a crosshead screwdriver
and a 5 millimeter allen key. Then follow

these simple steps. All you need… Oh,
[beep], screwdriver won’t come out. Sorry.

Front indexing in a nutshell, there’s
two things to remember. Firstly,

that the limit screws adjust how far
the derailer can move either out or in,

but to actually control the movement of
the derailleur, that’s all down to cable

tension. So limit screws limit the
derailleur, but they don’t adjust the

movement. That is down to cable tension.
Firstly, we’ve got the derailleur clamp

bolt here, and that sets the height
and the angle of the derailleur.

Once set, that should never move but it’s
always worth checking as part of the

indexing process to make sure it’s
in the right place. Then, we’ve got

two very important screws, the
high-low adjustment screws.

Now, essentially, these stop the chain
coming off or making noise whilst you

ride. This inboard one here, that’s the L
screw. That stops your chain coming off

when you shift into the little ring.
And then this outboard one here,

that’s the H screw, and that stops your
chain coming off when you shift into the

big ring. Then, this final thing here,
we’ve got the cable clamp bolt, and that

changes the cable tension in the system
which is how your shifter relates to the

derailleur. We’ve got quite a crude
adjustment here by loosening the bolt and

then putting the cable in,
but we can do finer tuning.

Up here, we’ve got a barrel adjuster
which means that we can dial in the

perfect amount of cable tension. As I
said, if your shifting’s already been set

up correctly, then the height and angle
of your derailleur should be already okay.

But to check, the derailleur should sit
about two millimeters above the outer

teeth of the outer ring when the chain
is on the little ring. So, in this case,

we need to drop it down a little bit, and
we do that just by loosening that screw a

touch there. Don’t forget, any adjustment
you make to the height of the mech will

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therefore have a knock-on effect on the
cable tension, so put your indexing even

further out. To get the angle of the mech,
the plates should be parallel to the outer

chainring. Unlike the height of the
derailleur, the angle actually can

sometimes move. If you ever jammed your
chain quite violently in there, then it

can shift, so it’s always worth having a
good look at that. So once you’re sure

of the height and angle, then it’s time
to turn our attention to the actual

indexing. I’m gonna start with this
low-limit adjustment screw here.

So, first things first, put the chain on
the little ring and then also on the

biggest cog at the back. Then, when the
chain’s in that gear, we need to turn the

L screw so that the derailleur is sitting
one millimeter away from the inboard edge

of the chain. So we need to screw it
anti-clockwise to move the derailleur

inboard and then clockwise to move it
outboard. Now, what this does is it stops

that really annoying noise when you’re in
the easiest gear, and you’re climbing and

also it prevents the chain from coming off
when you’re shifting into the little ring.

If, when you’re turning the L screw
here, and the derailleur stops moving,

that’s because, in all likelihood,
you’ve got too much cable tension.

So you can either slacken it off a little
bit here or, better still, undo that bolt

completely and let the derailleur rest
in its natural position, essentially,

starting from scratch. Next, we need to
look at the cable tension, which is, as

we’ve said already, what actually controls
the shifting part. So, while pedaling,

change down a couple of gears at the back
and then try and shift into the big ring.

Now, if it doesn’t go, that means you
don’t have enough tension in the cable,

so you can try and sort that out by
using the barrel adjuster up here.

So unscrew it until it does change, or, if
you don’t have enough barrel adjuster to

move the cable far enough, then, again,
loosen that bolt and pull the cable

tension in by hand. If it changes, or
indeed overshifts, then the next step is

to turn our attention to the H screw here
which limits how far out the derailleur

can move. So what we need to do
is, with your chain on the big ring,

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change down into your highest gear, and
then we need to adjust the outer plate of

the derailleur so it sits 1 millimeter
away from the outer edge of the chain.

There’s a bit of a theme going
on there that you can tell that.

We’ve now set our lower and upper
limits, and we need to test it out.

So shift back into the little ring and
then back into the big ring. If it won’t

shift back into the big ring, because,
don’t forget, we’ve limited the movement

now of the derailleur, then we have
too much cable tension in the system. So,

then it’s a case of backing off our barrel
adjuster here and allowing the derailleur

a little bit more leeway. Don’t forget
as well to test it out at different gears

at the back because that affects where
the chain sits. Now, you notice that

in our smallest cog at the back in our
little ring, there is still a little bit

of noise, because the chain is rubbing
on the derailleur. Now, on Shimano, that’s

just how it is, so they have added a
little trim function into the derailleur.

It’s like a half click that allows it to
silence it. But, if I’m being completely

honest, I would never ever, ever ride in
this gear, so it’s not really a problem.

To sum up, if your chain falls off when
you’re shifting into your little ring or

it rubs when you’re climbing on your
easiest gear, then you need to tighten the

L screw. If you can’t change into your big
ring, then you need to increase your cable

tension by adjusting the barrel adjuster
here or the cable clamp bolt there.

If, however, the chain comes off
when you’re shifting into your big ring,

then you need to back off the cable
tension a touch and then also tighten the

H screw. Unfortunately, it doesn’t always
go smoothly. There is an element of trial

and error in sorting out your front
indexing, but it also could quite likely

be something other than a problem with
your mechanicing skills. So, here are the

most likely causes of problems with
your front indexing. First things first,

sticky or gritty cables will ruin your
shifting. Now, you’ll feel it, because

your shifter will be really heavy, but
what it also means is that the little

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spring in the derailleur can’t
overcome all the grit in the cable.

So it struggles to move back down when
you shift down, so that will manifest

itself by struggling to shift into your
little ring. However, it could also be due

to corroded pivots in the mech itself, and
that is because they get sticky, and then

that stops the derailer moving freely
as well. If that’s the case, you could

try spraying on a solvent-based degreaser
and then a lube, but it’s quite likely

that you’ll actually just need to buy
a new front derailleur. Sorry about that.

Then, finally, if both those things are
working okay, and your shifting’s accurate

but just slow, then it might be a problem
with your chain and your chain rings.

Worn drive chain parts do mean that things
slow down in the shifting department so

have a look to see whether your chain
needs to be replaced and then also your

chainrings. We’ve got a video showing
you how to do that. You can get to it by

clicking up there. Finally, it’s worth
saying that even the very best-adjusted

gears do have their limits. It’s no
coincidence why just about every

pro cyclist has a little chain
catcher down there to stop the

chain coming off when they
shift into the little ring. So, to get

around this problem, you just need
to pre-select your gears before you

really need them. So, what I mean is don’t
wait until you’re grinding to a halt up a

climb before you try and shift from
your big ring to your little ring.

Think ahead, shift in advance, and just
take a bit of pressure off the pedals when

you do try and shift, and that will help
things no end. Now, your front indexing

is working perfectly. You also need to
make sure your rear indexing is dialed as

well. So, to do that, watch the video up
there explaining exactly how to do it.

But if you are in need of a change of
cables to get your front dialed then why

not watch the video down there
about how to change your cables?

Finally, so you don’t miss another
GCN video about maintaining your bike,

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