How To Set Up A Front Mech On A Mountain Bike | MTB Maintenance

How To Set Up A Front Mech On A Mountain Bike | MTB Maintenance


– 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. And if you want to watch
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to adjust your rear derailleur and click down there for
how to clean your chain. Don’t forget, if you’ve
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