- This is the GMBN Tech Essential series.
It's our easy to follow guide to setting up your bike
and maintaining it yourself at home.
In this video we're showing you how to
replace your chain and cassette.
These are consumable parts of your transmission
that endure a lot of abuse from pedaling and shifting
and, of course, the conditions you actually ride in.
They wear out and will need replacing.
Which is actually a pretty simple thing to do.
So here's how you change them and
what you need to do that yourself.
To do this job at home you're gonna need a few tools.
First up you're gonna need a chain wear indicator.
It's a really useful tool for any mountain biker to have
cause you can monitor the wear of your chain
which in turn will tell you when you need to replace it
and of course that cassette as well.
You're gonna need a cassette removal tool.
There's various different types.
You're going to need one that's compatible
with your particular setup.
And then, to go with that, you're going to need a chain whip
and you're also going to need either an adjustable spanner
or a vise in which to hold that cassette tool.
You might also want to have some protective rubber gloves
cause it can be a bit of a greasy job.
Some chain lube for afterwards, some shop towels,
and, of course, a chain splitter.
Now, first up is the question, when do you actually need to
replace your chain and cassette.
Now there's no actual fixed rule or fixed mileage
especially with mountain bikes when you should be
replacing these items cause it totally depends
how often you ride, how hard you ride,
how hard you smash through those gears,
and of course those weather conditions that you ride in
and, of course. actually how well you maintain
or how well you don't maintain your bike.
Because mud and grime and all the other stuff
builds up and it makes this horrible grinding paste
which can wear things out quicker.
Which is why we always tell you to look after your bikes.
Now having a chain checker is a really good thing to have
because it's sometimes possible to get
two or three chains worth of use out of one cassette
if you make sure that you replace your chain
before it's completely worn out.
The reason for that is the chain will
minutely stretch over it's time on the bike.
Basically, all that means is, it will be contacting
different parts of your sprocket the way it's designed to
and, of course, that will make it wear out those sprockets.
So what you're looking for is using a chain checker
such as this there's a few different types on the market,
it indicates the amount of stretch on there.
If it's above .75 you basically got to
replace that chain immediately.
It's really really worn and, at the same time,
you're going to need to replace the cassette as well sadly.
If you've got 10 or fewer gears on your bike,
say seven, eight, nine, or 10 speed transmission,
you can go up to .75, that's your roof
of where you need to replace it.
If you've got 11 or more gears
it's .5 when you should replace it.
The simple way you would measure that is by
slotting the tool straight into the chain there
and simply adjusting until it's a firm fit
and then basically looking at the number,
reading what the inside there and that will
correlate to if you need to replace your chain,
if you need to replace your chain and cassette immediately,
or if you've got a bit more wear to go.
But, remember, you can always get more life
out of a cassette if you're quicker to replace the chain.
Which, of course, will save you money in the long run.
Now, the reason you want to make sure
you replace the chain sooner rather than later
is simply because as the chain stretches,
even though it's a minute amount,
you'll never be able to see the search of your eye.
Think how precise that initial components are
in the whole transmission.
Although the transmission of a bike is
quite mechanical in the way it operates,
it actually needs to be quite precise.
So any sort of stretch you're gonna get on the chain,
the chain's not going to sit correctly on those sprockets
and when you put a load through it,
it can actually put a load on the wrong part
of the actual teeth there, which over time,
will actually turn those into little sharp fins
and then the chain's never gonna grip on them.
So as a result of that you can get chain slipping.
You'll get problems with shifting.
A whole number of other issues.
I have seen people hold onto the same chain and cassette
combination for years but they've always been plagued by
terrible shifting, snapping chains, all that sort of stuff.
If you want your drive train to work well
and be as efficient as possible keep on top of this stuff.
So when it comes to replacing your chain and cassette
you've got a few options available to you.
If you're doing a straight swap it's nice and simple.
You pretty much want to replace like for like.
At this point you have the option of upgrading your chain
and/or cassette for something slightly higher quality.
Which might mean you either save weight
or you increase durability, or, better still, both.
So those options are available to you.
There are two main types of cassette out there.
There's the SRAM pattern and there's the Shimano pattern
which is a bit more classic.
So a Shimano pattern involves a hub with
splines on just like this one here.
Now the way the cassette works is the cassette literally
slides onto those splines and then the lock ring,
like this one in my hand, here slides onto the end
and squeezes the threads on the free hub body
of the hub itself to secure the cassette in place.
If you're using the SRAM system
it's a slightly different system.
The cassette still comes off in one piece
but the actual carrier system is slightly different.
So it pushes on and the whole cassette
threads onto the actual body itself
and the reason for that is the SRAM cassettes
tend to have this tiny little ten tooth sprocket.
To allow this they can't use a traditional locking system
because, simply put, the ten tooth is too small.
So they invented their own carry system
and it has it's own separate free hub body
known as the XD driver.
So if, at this point, you're gonna be replacing
a SRAM cassette onto a SRAM XD driver
it's quite a little simpler than
replacing the Shimano style equivalents
where you actually have to push on each part of the cassette
bit by bit onto those splines.
With the SRAM style cassette it's a one piece unit
so it's a lot more simple, and it's just a case of
literally sliding onto the body there.
In an ideal world you want to make sure
this is nice and clean and greased.
This is just to demonstrate how the system goes together.
You then simply insert your cassette tool
into the bottom of the cassette there.
Now using your adjustable spanner, or if you've got one
put the whole into a vise, and spin it around.
When it's getting all fine this way on
you can pretty much use it as a ratchet.
There we go.
Now there are various different models of chain
available in the market.
Now SRAM will always recommend using
a SRAM chain with a SRAM cassette.
And the same with Shimano and Shimano cassettes.
However, there are some other brands available
in the market that are compatible with both options.
So there are no issues there.
The most important thing is you choose
the correct speed chains to go with your cassette.
10 speed chain with a 10 speed cassette,
11 speed chain with an 11 speed cassette, and so on.
This particular one is a chain made by Box Components.
Comes in a box, nice and simple
and it has it's own joining master link.
Now most chains these days will come with
some kind of joining master link.
It simplifies the process of joining your chain.
You pretty much can't get this wrong.
It's a very simple process and we're just gonna
guide you through how you do that.
So before we go into taking the chain itself off the bike
in order to replace them, let's have a look at
a couple of the tools available to do this.
Now the obvious choice is to use a chain splitting tool.
This is a workshop sized option,
we still have the super size for easy use,
but you can get these on various different multi-tools
that we actually use ourselves as well.
Now on the multi-tools that you tend to get
you'll get ones that have single
and twin jaw options on there.
The first set of jaws will sit
nearest the outside of the tool.
That is your classic set for just holding the chain
in the correct position to drive the pin out of the tool.
You then flip the tool around to push the pin back in.
But, as a result of that, sometimes you'll actually
squash the outer links against the inner links
causing a stiff link.
If that happens you would then put the chain
into the secondary set of jaws.
While being held on the secondary set
the outside links can be pushed away fractionally.
We're talking the tiniest bit and all you need to do is
just adjust the tool up against that.
Of course that isn't a problem we have here.
All we need to do is split the chain.
And that's as simple as sitting the chain on the tool
and driving that pin out.
Use the driver to make sure it sits on their squarely.
Then you can tighten up, there's usually a click
as it unseats the pin from the other side.
And then you can simply pull the links apart.
The other option is you might be lucky enough to have
some of these or have access to some of these.
These are called chain splitting pliers.
Now, if your bike has got a master link of any kind on there
like this one has, you can use these pliers
to split that, bang, pops open, and you don't even
need to use the chain splitter.
You can identify the master link by the markings on it
and you can see in fact it's got an open section.
This is so when I split the link it can come apart.
The pliers simply go either side of this
and you literally pop them together
and you'll see that pin move just like so.
And the chain can literally be pulled apart.
You can take off those pieces of master link.
Now just before you split it you want to make sure
you're shifted into the smallest sprocket in the back
so the chain has the least amount of tension on it.
It makes the job a bit easier for you.
The next one, if you're lucky enough to have
a SRAM derailleur on your bike,
they have a lock on them so you definitely want to
make sure that lock is engaged.
Again it just takes all of the tension off the chain.
If you've got a Shimano derailleur on there
and it has clutch just make sure you turn that off.
Now just an additional safety point for later on,
as a mountain biker, if you need to split and rejoin a chain
at any point if possible rejoin them using a master link.
Now using a chain tool you can split and rejoin
as many times as you fancy but, on many modern chains,
the pin shape itself is slightly flanged at one end
when it sits onto the outer plate on the other side.
When you push it out and push it back in again
the fit will never quite be the same again
and it creates a weak link within the chain
and, of course, if it's gonna snap anywhere
that is exactly where it will snap.
So for that reason you should always try to
make sure you keep a relevant master link,
10, 11, 12 speed, whatever it is to suit your chain.
Keep one of those in your riding bag.
With the chain removed from the bike your next job is
simply to remove your rear wheel.
Because the chain is already removed
this makes it a lot easier.
The rear wheel will just slide straight
and you've for access to that cassette.
Now in order to remove your cassette
this is where the chain tool and the cassette tool come in.
Now the reason you need these specific tools is
cassette tool slides onto the lock ring here
and is used for undoing the lock ring.
But of course, because the whole system has
a freewheel on it, if you were just to undo that cassette
tool with it in place it would spin the cassette backwards.
So the chain whip's job is to hold the cassette still
in order for you to undo that lock ring.
So at this point you can decide if you want to
mount your tool into a vise and then you can use
the chain whip and then turn it in the direction to
undo it or, like I'm gonna show you,
using an adjustable spanner.
So there are various different patterns
of chain tool on the market.
This is the pretty standard one but it's actually got
a new feature on it just to slide on
the inside of though axles.
You don't actually need this one.
You can happily do it with
one of the original star ones as well.
It's a case of literally sliding this into the end
so that it mates with those splines nice and secure.
Next up, you put the chain whip around the cassette.
The higher up you go the more leverage you've got.
Now remember this is just to hold it steady.
You're actually doing the undoing motion with this.
Don't get drawn into trying to undo it with the chain whip,
like I've seen many people do,
and then the chain whip actually slips.
The obvious way to do this is having the wheel
between your legs using your weight advantage
to push it down and loosen that lock ring.
Once it comes loose you can remove the spanner
and chain link from it and just using the tool
with your fingers just undo it
and then remove the cassette in pieces.
I first need to note before installing your new cassette
is the orientation of the splines.
Now on the classic Shimano pattern
you'll see that one of these splines,
this one here at the middle of the top here,
is slightly bigger than the rest of them.
So you're gonna make sure, obviously,
that that correlates with the biggest spline on the hub
itself before you can slide them on successfully.
Now when you're installing these you pretty much have to
do them one by one, so again, make sure they
go on the spaces in between them and you've got them
in the correct orientation so the number,
this one's a 19 tooth, make sure it's facing out towards you
otherwise you're going to be sitting there
trying to get the thing on.
You're not gonna get it on.
Okay so literally just take the time
make sure they're lined up correctly
and it will slide on nicely.
Make sure you send them home.
Again, next one up, slides on.
Next one is a spacer so, again,
make sure the orientation is correct on there.
I've got the big slot facing me just so I can see that.
Nice and easy.
(down tempo music)
And then when you've got all of them on
and you check that it's all pushed down
and is seated correctly, then it's time to
get your lock ring and slide that on the end.
Now this particular hub has already
got a bit of grease on it but it's well worth
putting just a smidge of grease
just on your threads there to make sure
it can go in nice and tight.
You should be tightening the lock rings to 40 nutometers
as it specifies on the outside there.
If you haven't got the torque wrench at hand
you can just tighten these up fairly tight.
There we go.
And you're good to go.
Now just before going any further
I'm just gonna give the derailleur itself
a bit of a wipe down, make sure those guide wheels are
nice and clean because I'm putting a nice new chain on there
so I want to make sure it stays shifting.
As clean as possible for as long as possible.
And of course with that dirt and grime,
it can get in the way of that stuff.
So just before you install the new chain
you're just gonna make sure it's the correct length.
Now this is the easy bit because
you've actually removed the chain from your bike
so pretty much hold them up and like for like
you want to match the lengths
and then split the chain at the relevant part.
Now with some 12 speed chains there is an orientation
to where the chain has to sit against the extra sprockets
but with this 11 speed one it doesn't actually matter.
So I'm just gonna run the chain over the drive train itself,
get this in place, ready for rejoining.
Make sure that you correctly route the chain
around those guide wheels, it goes over the top one
under the bottom one there.
Then you'll be in a position to get those links together.
Now this is the fun bit.
You've got your two bits of the master link
so pass one through one end of the chain,
the other through the other end.
And, of course, you just want to simply join them up
by sitting them on each other.
So there you go they're sat in place.
I'm just gonna try to pull them tight, there we go.
Now just want to make sure that these are snapped in place
And the best way to check this is cycle this power link
or master link all the way until it's in the top end here
and in that way put your back brake on,
put some pressure on the cranes and it will pull against it.
They actually find with any new chain
it's got a very sticky sort of residue on it
and that's factory grease that's part of
the chain manufacturing process.
Now there's two schools of thought with this residue.
Some people like to degrease the chain
before they even get it onto the bike
and make sure they're starting fresh.
But I actually think that
that factory grease is pretty good stuff.
However, it is very sticky, so I like to
just put a bit of WD-40 on a rag,
not applying directly to the chain,
and just use it to wipe the outside links clean.
The reason for that is that sticky residue
does attract a lot of dust, grit, and all that.
So horrible stuff that does wear your chain out.
I'll then do my first few rides,
depending on weather conditions,
then when I next clean my bike,
then I will apply a decent chain lube.
And of course the last thing you want to do is
just cycle the bike through the gears,
make sure everything is lined up nicely,
and it's working and you're ready to hit the trails.
It's that simple.
But, of course, don't forget to
get yourself a chain checker tool.
They're really, really worth the money
cause it does mean for every cassette
you're likely to get a couple of chains out of it.
For a couple more useful videos
click down here on how to change all the gear cable housing,
the inner cable, the outer cable, the whole lot.
And click down here if you want to know
everything about the derailleur,
how it works and how to index your gears.
As always, if you like GMBN Tech give us a thumbs up
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