- So welcome to another GMBN maintenance video.
In this video we're talking about something
that you guys have been requesting.
It's how to adjust a front derailleur.
Now I'm gonna be totally open and honest
at the start of this video.
I don't really use a front mech that much.
This is my cross-country bike,
and I'm gonna try my very best
to teach you guys how to adjust it
and set it up so it's running smooth.
Okay, so with that front mech,
there are five points of adjustment.
The first one that I want to talk about
is height and also the angle at
rotation front mech is at.
Then I want to talk about the low and high limits
of the actual mech itself
and finally, the cable tension.
Now believe it or not,
you're only going to need two tools to do this.
In my case, it's a two mil allen key
and also a four mil allen key.
You might find that you need a Philips screwdriver,
so just check on the manufacturer's guidelines.
So to start off this process
you're gonna have to have that chain in the lowest,
smallest chain ring.
And then we're gonna thread that chain
through the front derailleur.
Once we've got that, it's all about attaching
the front derailleur onto the bike itself.
You're gonna clasp it onto the seat tube of the bike.
I've got a mount right here
which actually fixes
and only gives me up and down adjustment.
You might have actually angular adjustment
where you can rotate it round
and get that perfectly setup.
What you're looking for
is to almost be parallel above the chain ring.
So if you have it over-rotated either way,
you're gonna find that it's gonna rub in that front mech.
And it's just not gonna be as efficient
and it's gonna give you a horrible grinding noise
when you're peddling the bike.
Now it comes on to actually setting that height.
If you've got it too low,
when you go to shift up,
it's actually gonna catch on this chain ring right here.
If you've got it too high,
well, the problem is, that chain could actually come off
the chain ring and you're gonna drop a chain,
which you do not want.
The perfect scenario is to have it
just about two mil above that chain ring.
It's gonna be able to shift perfectly over it
and you're gonna hopefully keep
that chain in the correct position.
So let's use my four mil allen key
and attach that on.
Okay, so with the mech now set in adjustment position,
what we're gonna do is bring that cable through.
So you're just gonna have to thread that through
the little hole here.
Just get that all lined up.
Okay, so now it is all about
just getting that cable set through.
Just gonna pull it through
and you've got to get this all lined up
so it just sits into that grub screw.
Then I'm just gonna use my four mil
to tighten that back up.
Now later on we can actually finer adjust this
using the barrel adjuster up at the front shifter.
Let's move on to adjusting those high and low limit screws.
We'll start with the low one first of all
since we're in the lowest gear,
and you want to shift onto the rear derailleur.
You want to make sure that it's in the biggest
cog or first gear.
So let's have a look.
Okay, so put my allen key in.
I'm using a two mil,
you might be using your flathead
or your Philips screwdriver.
If you actually wind that in,
you're gonna see that that's gonna move that mech
up towards me.
But if you wind it back up,
that's gonna move it in towards the frame.
Where you want to have it,
is just so it's touching the chain
and then you can wind it off ever so slightly.
Because you don't want that rubbing,
because again, you're gonna get that horrible noise.
The kinda metallic chain against metal sound
that you just do not want.
So let's get that set up.
There we go, there's about a mil or two mil gap.
Just enough in there
that the chain is not gonna drop off
and it's gonna keep in place.
Right, so we've got the low setting now adjusted.
It's gonna be time to move it
into that big ring to adjust the higher setting,
or the H that is on that front derailleur.
Just gonna move up to the handle bars
and just get that front shifter
and move onto the big chain ring.
So you can hear there that click
of it going into the next cog,
and hopefully it's gonna shift up.
There we go, shifted right up.
Now if that hasn't happened for you,
there's two things that could have gone wrong here.
You could have adjusted the wrong angle
and the height,
or you could have the cable tension
at the wrong amount of tension already.
So just go back and have a think
about how your front mech is actually moving,
and watch it move when you use that trigger
on the front shifter.
Okay, so now that we've got that in position,
we're gonna go on to setting that.
I'm gonna use my two mil allen key again.
I'm gonna pop that into the little hole there.
I'm gonna show you how this one moves.
So that's just be taking off the tension.
So by winding it anti-clockwise.
It's just gonna move it further out towards me.
Then by putting more pressure,
it's gonna move it in towards the frame.
Now the cable tension at this point
does have quite a big effect on it.
Because it's at its maximum, sort of, rated tension already,
you're not gonna be able to push it in too much,
'cause the cable is actually gonna
try and stretch
and you could end up damaging that front mech
if you put too much tension on it.
So just have a look.
Let's have a see where this is at.
So I'm gonna pull this out a little bit more.
Again, because I'm in my biggest gear on the rear,
you can just pull that out
and you can look for that.
I mean, you're not really ever gonna have
ideally your big chain ring
and you're big cog on the rear,
'cause if you're on full suspension bike,
you'll probably find that it could extend
that chain a little bit too much
and you could end up damaging the chain itself.
So I've got that just about in the right position.
Where it's not actually gonna drop down
onto the lower cage
and it's not gonna skip over the chain ring
and gonna drop the chain.
So let's now shift down the gears
and we'll make sure that it all lines up
through the whole cassette.
Okay, so I've shifted down the cassette.
It's now in the lowest or the smallest cog
at the rear of the bike.
We're just gonna check that one final adjustment
to make sure that the chain itself
isn't actually rubbing.
That actually looks almost perfect.
The chain line is spot on.
This lowest cog is not rubbing on anything
and when I shifted it back up
it wasn't touching anything.
And of course, the most efficient point
is to be in the centre of that block
with the chain almost parallel,
completely the whole way through that chain ring
and also through the front mech.
Now we can talk about going on
to adust that barrel adjuster
to fine tune the cable tension,
to make sure that it's shifting up and down fast enough.
Okay so I'm gonna come up to the other side of the bike now
and work with that front shifter.
I've got everything dialled in down here
in terms of actual adjustment.
But it's all about that fine tuning
and adjusting the cable,
using this barrel adjuster.
Now if you wind that clockwise,
for you guys what that's actually gonna do
is really just push the cable
so you're gonna have more slack,
you're gonna have less tension.
Pulling out, which is anti-clockwise
is gonna give you more tension.
So this is gonna really effect
how fast it shifts up and down the front derailleur.
Let's have a look and see where we're at.
So again that's pretty good.
It's not too bad
but we could probably get a little bit faster going.
So what I'm gonna do is add some tension.
Just so it shifts up that little bit quicker.
So if I just go by pulling this out.
That's gonna give me more tension on the cable,
which should mean it'll actually pull that through faster.
We'll do that once more.
See the difference right there?
There's just a couple of teeth difference,
faster shifting and back down it's spot on.
Again guys, this is really trial and error.
You might have to play around with it
to get that absolutely perfect.
So there's two things left
that if your front mech is not shifting well
you could actually think about.
Number one is that if your cables are old and worn
then you could find that pushing that lever
might actually be quite hard.
So you could think about changing them.
And also, just make sure
that you keep that front mech lubricated
Because if you're getting grit,
sort of winter riding grime getting in there
then it can really corrode it
and it's not gonna shift up that smooth.
Now if you've got any more mechanicals
that you want to know about,
then leave them in the comments section below.
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Click right up there for how to adjust your rear derailleur
and click down there for how to clean your chain.
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