- Hello everyone.
I'm Henry from the GMBN Tech channel.
So, today we're going to be looking at substandard shifting
and inexcusable indexing.
You guessed it, we're going to be looking at our rear mechs.
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Now, we adjust our rear mechs by changing two things.
Our cable tension, which affects how the chain moves
from one gear to another,
and our limit screws, which affect how a derailleur sits
at its outer extremities.
Now, before we even touch our cable tension,
I want us to look at our limit screws.
Now, we do this first so we don't potentially
damage our frame or spokes as the chain rides off,
and also it provides a great starting point for our setup.
We want to adjust these screws
so the center of the jockey wheels line up exactly
with the applicable gear on the outer reach of the cassette.
So, with these screws, the more you dial them in,
the more it limits the movement of the mech.
So, on some derailleurs, you have a H and a L to signify
your high and your low limit screws.
But not always.
Like this one, for instance, doesn't.
But a really easy way to do it,
is you dial it in,
and then back it off.
And you should be able to see movement,
but it's really important you dial it in first
because then you're not going to risk
losing the chain off the cassette.
And it could potentially damage your frame or your spokes.
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Now, when we put a new cable in, it's really important
to make sure we have some adjustment left
on the barrel adjuster, should we need it.
So, what I'd like to do is dial it all the way in,
and then turn it anti-clockwise
about two and a half, three, revolutions.
Now, this means is if I do the cable too tight,
I can then release tension from the system
with the barrel adjuster, here.
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So, once we've lined up our barrel adjuster
with that three turns,
we then set the cable at the other end.
So we pull through a nice moderate tension,
and then nip that bolt up to the appropriate torque.
Now a really simple way to index your gears,
is to move up through the cassette.
And you're going to go two gears at a time.
So two clicks.
And it's actually getting hung about in that middle gear.
So two clicks.
Yet again, it's getting hung about in this middle gear,
when it should have gone straight to that one.
So that would suggest there isn't enough tension
on the system.
So I'm going to add a bit of tension.
Now I'm going to work my way back down the cassette.
Now I'm going to shift two down,
so it should go to this gear immediately.
But if it gets hung up on this gear,
it means there's too much tension on the system.
Oh, that's okay it's hesitating a bit.
So just by going up and down.
Think it needs a bit more tension.
We're just going to do it until it never gets caught
in that middle gear.
Also, you can use your ears a bit,
if it's ticking a lot in one particular gear.
(gears ticking)
Yeah that looks pretty good now,
it's going straight into it.
Now, in an ideal world, we don't want to be using
all the adjustment on this barrel here.
Because we might need to make some quick adjustments
when we're out riding.
And if there's already maximum tension,
then you won't be able to add any more.
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As we move through our gears, up the cassette,
you may notice that on some of the larger cogs,
getting to those dinner plates,
the chain, or even the jockey wheel,
might foul a little as it goes along.
This is where B-tension comes in.
B-tension adjusts how far that top jockey wheel
sits away from the teeth of the cassette.
If it's too close you might even hear a prang
or a rubbing noise as it goes up into the larger gears.
And if it's too far away, you might even get a really
sloppy or inconsistent shift
down the smaller blocks of the cassette.
So what I like to do, is dial in the tension,
until on the biggest gear, the teeth of the jockey wheel
are just nearly kissing, are a few millimeters
away from kissing the teeth of the cassette.
Some companies even provide little tools,
such as Eagle, you get that little red tool,
but you don't really need it.
It shouldn't make a "vrr" noise,
if it does, it's too close.
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Now if you're really struggling
with getting the desired performance from your rear mech,
it's really worth thinking about factors
that might affect this.
So I would think about a worn chain, worn cassette.
Things like your inner cables,
are not only very cheap to replace,
but have a dramatic effect if they come across corrosion
or get any dirt in there and things like that.
So for a relatively cheap part,
it can really affect how your whole very expensive
and nice bike feels.
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I think sometimes companies label things e-bike specific
or e-bike this and e-bike that.
And sometimes I feel it's a bit of a gimmick,
however drivetrains is somewhere
that I would beg to differ.
E-bike drivetrains are stiffer, heavier
and more durable, and they allow for more torque
to be put through the system.
An example of this is just looking
at one of these chains.
You can see the bushings and the rollers
are just so much meatier and that provides
a stiffer interface for the derailleur to work.
As you can see, these rollers are so much bigger
than on a standard chain.
And it's actually not unheard of for downhill teams
to use e-bike specific chains,
just so when they're a load of the gears out
of the start gate that have a stiffer and sharper transfer.
So it's really as simple as that.
Changing and adjusting your gears
doesn't have to be this huge undertaking
that takes up hours, it can rather be a quick adjustment
before the start of a ride.
Now if you want to see how Jonesy got on,
testing the new Merida, click here.
And if you want to see those two pillocks
just falling off their bikes, click down here.