- Welcome to the next installment
of the GMBN Tech Essentials series
where we'll be providing you with some valuable know-how
and along with some basic tool advice
so that you can service and maintain your bike
to last a bit longer and save you
some pennies in the process.
Today, we'll be looking at how to replace your
disc brake pads and bed them in.
Now, in mountain biking speed and control are your friends
so it's certainly an area not to be neglected
for safety and performance purposes.
So, when should you change your disc brake pads and how?
(hip-hop beat music)
So, there's nothing more scary than hurdling down a trail
and losing confidence in your braking power.
Now, it could be that your brakes
are singing the song of their people
which is that really high-pitched screeching sound.
(high-pitched screeching)
It could be that your wrenching back on your levers
and they're just not biting
and you don't find yourself stopping.
Now, there are a number of reasons
why your brakes may be failing
but the most common one is just down to your brake pads
and they're pretty easy to sort out and replace
so here's how we're gonna do it today.
Now, you may think you need new brake pads
because they don't feel as responsive or grippy
when in actual fact they've done something called glazed.
Now, glazing happens when you're using
your brakes quite a lot, they get quite hot,
but they aren't given enough time to cool down.
So, maybe if you're a little bit like me
and you quite brake heavy and you do love your brakes,
this can happen so the best thing to do
is check your brake pads, see how much you have left on them
and if you have quite a lot left,
take them out, give them a sand-down
to remove that surface contamination,
pop 'em back in, and they should be good as new
but just remember to lay off the brakes.
However, if you do check your brake pads
and realize that there's not actually much left on them,
maybe a millimeter and a half,
then it is time to change them up.
Same goes if they're damaged
or if you're changing your riding style
by going somewhere new or racing,
then it's a good time to put in some fresh brake pads.
(hip-hop beat music)
Now there are many different types
of disc brake pads available
and if you go onto an online shop,
you'll be faced with pages and pages of them
so it can be quite confusing
but really there are only two things you need to know
and that's shape and compound.
There are a few different shapes
of disc brake pads out there
but only a few of them are specifically designed
to fit your brand and model of caliper.
So, be sure to check what braking system you are running
and make note of it so that
when you come to do some shopping,
you know which ones you're gonna buy.
So, once you know which brand and model
of disc brake pads you need,
you need to then consider compounds.
Now, there are three different compounds on the market.
There are sintered, semi-metallic, and organic
which is also known as resin.
Now, disc brake pads are a little bit like new tire choice
and so as long as you get the right shape and size
for your bike, they do work but like tire choice,
they each have different traits and properties
to suit different riding styles.
So, let's take a look at these compounds
in a little bit more detail.
First up, sintered brake pads.
Now, these are made with metal particles
like copper and bronze which are then fused
with other particles to make them quite robust
so they actually have quite a good lifespan.
Now, because of the way in which they are made,
they can withstand high temperatures
so perfect for downhill riding for example
and they tend not to glaze over
as easily as other compounds.
However, sintered pads have been known
to take a long time to bed in properly.
They can be quite noisy but then again,
on another plus side, sintered brake pads
do reduce brake fade over time
which means you get your braking power for longer.
Next up we have organic disc brake pads,
also known as resin.
Now, these are made with fibers and organic material
so that they're bonded together in order to give you
great initial bike feel, they're not as noisy,
and they're actually a lot easier to bed in
than the sintered pads.
However, organic disc brake pads have been known
to work less in wet conditions
and they also do actually wear out
a lot quicker under high temperatures.
Last but not least we have semi-metallic disc brake pads
and these are essentially the best of both worlds
when it comes to looking at the best of the sintered pads
and the best of the organic pads
so they're made with a blend of both.
Now, this means that they work really well
under high temperatures, that they bed in quite easily,
they're not as noisy, and they do last well over time.
However, they do tend to glaze which is a bit of a drawback
and the other problem with semi-metallic pads
is that the ratios of metal particles to organic
will vary between different manufacturers
so it may take some trial and error
before you find ones that you really like.
(hip-hop beat music)
Right, so you selected the right shape and compound
for your brake system as well as your riding style
so let's get them fitted.
First things first, whenever you go and carry out
any maintenance on your bike, it's really good
to just give it a proper clean first.
This just removes any grit, grime,
pieces of trail and debris
that might be sticking out of your bike
just so that you got a clean bike to work on
and especially when you're doing your brake pads,
you wanna make sure those calipers are clean
so that you can check alignment
and you can get a proper seat in for them.
Once your bike is secure in its bike stand,
it's time to remove the wheels
but be careful you don't want engage those brake levers
because that will cause pistons to close
and it can compromise the whole brake system.
So with your wheel out, it is time
to push those pistons back.
Now, ideally you'll have something like this
which is a piston press but you can use
plastic tire levers as well or most people will choose
a flat-blade screwdriver.
However, this can actually damage the pistons
and the caliper, so if you're gonna use a flat-blade,
make sure you keep your old brake pads in
when you're pushing the pistons back
so you don't damage anything.
So, with the pistons pushed back,
it's time to remove your old brake pads
by unclipping or unscrewing the retention system.
So, by unclipping these ones, I'm gonna use
these pliers here to take them out.
Now, at this point, it's a really great idea
to properly clean out those calipers as well.
So once your calipers have been cleaned out thoroughly,
it's time to pop in your new brake pads in.
(hip-hop beat music)
So, you've got your new brake pads in the calipers
so it's time now to pop the wheel back in
and check for the alignment.
Be careful to still lay off those brake levers,
you don't wanna activate the pistons just yet
because you really should check for the alignment.
Now what you want is you want your rotor
to sit in between the two brake pads quite parallel
and even so all you do, just spin the wheel,
making sure you look directly down into the caliper
to see where that rotor is sitting.
Now, if you find that your alignment is a little bit off,
then all you need to do is grab yourself an Allen key
and loosen off the mounting bolt
off the caliper to readjust.
So when the wheel is moving freely in the bike
and you're happy with its alignment,
it's time to squeeze on that brake lever.
Now, this will engage the pistons to push the pads
against the rotor and you might need to do it a few times
just to pump it through
but you should start feeling that bite pretty quickly.
Now, you might have to make some minor adjustments
and tweak the position just to get it really dialed in
but really you're looking for both of the pads
to meet the rotor at the same time evenly and flat.
So, once you're happy with that,
it's really now a time to bed them in.
Bedding in your brakes is extremely important
because this will rub off any surface glaze
or contamination which comes from
general production and handling.
The best way to bed in your brake pads
is to find a flat, smooth surface like a car park
or just outside your house, then pedal some sprints
and perform some hard and sudden stops, safely of course.
Do this a few times to get the pads hot and engaged.
Now, you should feel a huge improvement
in your stopping power with the
bite point on your brake levers being a lot further out
so it's good to tweak your levers and reach accordingly.
After all, if you've been running worn pads for awhile,
you've probably been wrenching back
on the levers pretty hard.
So once you bedded in your new brakes
and you've adjusted yourself accordingly,
it's time to hit the trails and open them up.
And that's it!
So, if you've enjoyed this essentials video
and you got some suggestions for things
that you would like to see in the future,
please put them in the comments below
so we can check them out
and if you would like to see more GMBN Tech Essentials,
then click over here to where Doddy will give you
a comprehensive run-down on wheel axles
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