- There might be times where you're getting
a little bit of disc brake rotor rub
and no matter how much tweaking of the
brake calliper alignment you do,
you just can't get rid of it.
Now if that is you, then look closely,
because you actually might find that it has nothing to do
with the calliper alignment, it's your disc brake rotor
has bent slightly out of true.
It's not easy to do,
discs are really well protected when it comes to crashes...
they really are.
But actually, where they might be susceptible is where
you're transporting your bike.
So if you're stacking wheels up in a car,
or you forget to take the rotors off when you're flying.
Now, however it happened doesn't matter.
And actually, it's not too bad anyway,
because you can true a disc brake rotor...
and here's how.
Assuming that the calliper hasn't moved,
it should still be aligned to when
the disc brake rotor was straight.
And so that means that we can then use it as a guide
to determine whether the rotor has bent
inwards, outwards, or in fact, both.
Now here's a little hack to make
life a bit easier on yourself.
Take something light coloured, so like a piece of paper,
and then pop it on the floor underneath your wheel.
And that is going to help you distinguish between
pad, rotor, and calliper so that you can actually see
the whole alignment process much, much clearer.
Okay, it's time to actually true things up now,
and I'll admit, there isn't a great deal of science to this.
Ideally, you would have one of these, which is a
rotor truing tool, and it fits over the end of the rotor
and then, you simply bend the rotor very
gently in the direction that you want to move it.
And you'll find that they are relatively resistant
to small tweaks, so you may need to spend a bit of time
actually moving it into the desired position.
You may not have one of these though,
in fact, you probably don't.
In which case, you can use an adjustable wrench instead,
but you do need to be a little bit careful,
because obviously, it's not quite as deep
as the rotor truing tool.
And so you may find that instead of actually moving
the whole rotor in the direction that you want to go,
you'll actually just kink the brake track.
So, proceed with caution if you do use an adjustable wrench.
Now you do need a little bit of patience for this.
It's a relative time consuming process,
but keep eyeballing the rotor, keep tweaking it,
and eventually, you are gonna get it straight.
Might take 15 minutes... 20 minutes... That's not that bad.
Now one thing I would say,
is that if you try and get perfection out of
a slightly bent disc brake then you may well go mad.
What we're looking for is for it to simply
not rub the pads anymore.
So, almost perfect is good enough.
Now when working on disc rotors,
you probably don't need to be careful
of this bit of the rotor, it's actually not that sharp.
But one that that we really, really need to be aware of
is getting fingers caught in there.
Now, it sounds stupid;
why would you put your finger in there?
But people do it, and then... that's really gonna hurt
when the disc starts to turn.
And the other thing to bear in mind with fingers
is actually, a lot of people are really concerned
about the oils that you have on the surface of your skin
actually contaminating the rotor and the pads.
And so, if you are gonna start touching disc brake rotors,
then make sure you stick some gloves on,
or really, really thoroughly clean your hands first.
There we go then.
A simple procedure, and trust me,
I'm quite glad that we've done it
because the geeks out there will notice
that that is a very old disc brake rotor.
And actually, it's one of mine, and I've been meaning
to do this job since 2006.
Literally, that rotor has been in the bottom
of my tool box... just cluttering it up.
So there we go. Job done. Oh Yeah.
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And if you want some more related topics,
related videos, then if you click up there
we've got a video on how to stop brake squeal,
so whether you're using rim brakes or disc brakes
that will help you out.
Or down there, a video about whether disc brakes
are ready for the pro peloton.
It's an old one, but it's still a good one.