Hello and welcome to PowerDrift, this is Simplified where we take complicated ideas
and break them down into small bite sized pieces that you can use in your life with motorcycles.
And today we're talking about anti-lock braking systems or ABS. Before we go ahead, I invite you
to do the little things for us, subscribe, bell notification icon, like and if you love this
video, please do also share it to your friends, I think it might be useful. So anti-lock braking
systems, what the system do is technically in its name, anti-lock braking system and lock refers to
a wheel that's no longer rotating. Why is that a problem? As long as your wheel is rotating, the
biggest thing that you gain from it is the ability to control what that wheel is doing in terms of,
if you hit the brakes, if you hit the accelerator or turn the wheel, that wheel is able to react to
your input and produce a predictable result. Once the wheel locks up, once you're skidding,
it's very very difficult to exert any kind of reasonable control on this tyre and that's what
anti-lock braking systems prevent. So let's bust the first myth. Anti-lock braking systems
do not always reduce the stopping distance, that is a positive side effect in most conditions, but
it's not true for all conditions. So if you were to have a bike with ABS on gravel or on ice or on
snow, chances are your stopping distances will be longer with ABS than without and the reason is,
for example, some of these surfaces will form a little bit of a wedge in front of the tyre and
the wedge produces a much stronger retardation force than a rolling tyre with ABS active.
Right? How does the system work? In most cases, the ABS system's work starts with sensors on the
wheels that report to the computer, the ABS computer, what the state of the wheels are in
terms of rotation, many ABS systems are able to use just one tyre, so for example, if I have a
single-channel ABS system, which means it only works on one wheel, usually the front wheel,
the system can monitor if the front wheel is rotating or not, and calculate whether there is
an acceleration going on or a deceleration going on. Sometimes some systems use both the wheels and
compare wheel speeds with each other, which is why you have a single-channel ABS system which
operates only on the front brake, but you'll see the slotted rings on both the wheels. The slotted
wheel essentially is a little metal ring that sits on your hub and basically there's a small magnet
placed very close to it, and the magnet is reading the arrival and passing of the spokes of the
slots. When a spoke comes close, you get a spike in the magnetic force, when the gap comes close,
you get a depression in the magnetic force and the difference in this amplitude is what is used to
calculate how fast the wheel is rotating. This is why they say that if you're going to make a
drastic change in the size of your tyre, you might upset the calibration of the ABS and traction
control systems because both of them rely on that slotted ring and the known circumference of
the tyre to tell the system how fast the wheel is rotating, the system actually starts to work only
once it detects an unusual amount of deceleration, or a wheel speed that is approaching zero.
In both those situations, the computer recognises that there is a hazard coming and it needs to do
something. To do this something, what a ABS system adds to a normal hydraulic disc brake system
is a set of valves. Now these valves are essentially three positions and a small
overflow circuit and what they basically do is they control the pressure in the system
no matter what you're doing with the lever to ensure that the wheel continues to rotate.
Let's take the example of a simple hydraulic system or non-ABS motorcycle for example, right?
When you hit the lever, what you're effectively doing is building pressure in the hydraulic
circuit which causes the pads to come against the disk and press hard on it. If I keep doing this,
eventually the wheel speed will become zero. When the wheel speed is zero, but the vehicle speed is
non-zero, you have a skid, right? What an ABS system adds to this is the set of valves that I
spoke about and what happens when this wheel speed approaches zero but the vehicle speed is not zero
is that a valve opens and now you get an overflow circuit which is effectively like a longer pipe,
because the hydraulic fluid now has more space, it reduces the pressure in the system,
which means that the pads which are pressing against your disk, remember, they open up a
little bit and the wheel can start rotating again. As soon as the wheel starts to rotate again,
the system can start reapplying pressure and trying to slow the wheel down further
and again just before the wheel locks, the pressure will release again and this pressure
being built up and built down by the valve is what you feel as pulsing on the lever, it's also what
stops the wheel from rotating entirely. That's basically what an anti-lock braking system does.
You can add more electronics and intelligence to this. So if you have cornering ABS, for example,
then this system's computer is able to gain data about the lean angle of the motorcycle and make
further calculations as to how much pressure needs to be released and at what point the
pressure intervention needs to actually happen. And pressure intervention is one of the reasons
why you'll love some ABS systems and you'll hate other ABS systems. A lot of work goes into
calibrating how an ABS system will come alive and how will it function, alright, so there are two
or three things that go into this, one is how fast can the system cycle. So if you have a 10
hertz ABS system, it means it can intervene 10 times a second, which is pretty quick.
But faster systems can hit 50 hertz or even 100 hertz, which means the system is able to recognise
a problem a 100 times a second and intervene if it needs to, so you almost never feel the fact that
you approach lockup and more importantly, the pulsing in your lever is so small that you may not
feel it as anything more than a slight vibration whereas if I were to give you a system with five
or 10 hertz, because it's vibrating at a much, much lower frequency, you will feel it as an
actual pulsing off the lever. So if you look at older ABS systems, the pulsing was very strong,
modern ABS systems don't really pulse the lever a lot, you'll feel it as a vibration. The next thing
that can happen if you're using an ABS system and braking really hard, is that your rear wheel can
start lifting off as the motorcycle pivots around the front axle because of the forces involved.
Advanced ABS systems are able to recognise that this event is about to occur and to
prevent the front axle from becoming a pivot point around which the motorcycle rotates into
what is called a stoppie. This is officially called lift off control or rear lift mitigation,
depends on the manufacturer, but a racer, for example, will switch into race ABS and one of
the first things race ABS does is switch off the control over when the motorcycle starts to lift,
should we reduce the pressure on the front brake. This is because a racer is presumed to have a lot
of skill and once the rear wheel is 2, 3, 4 inches off the ground, he can continue to operate the
motorcycle because this event which is a very very extreme event in terms of what forces are in play
and how you generate it, but this extreme event is something that a racer is prepared for,
and he doesn't need intervention from the ABS at that point. So a race ABS motorcycle will still
unlock the front wheel if it locks up, but if the rear wheel starts to lift, it will not intervene
assuming that the human in charge has the controls and he knows what he's doing, in a sense,
that is how ABS systems work. On motorcycles in India, because of the way the rule was created,
we do have single-channel ABS systems, they only work on the front wheel, we do have a Simplified
episode on how braking works and how you should use your brakes which explains why the front
wheel is the most critical braking part of your motorcycle, it's not the rear wheel, which is
why single-channel ABS systems tend to go to the front wheel. You also have dual-channel systems,
which operate on the front and the rear wheel and 99% of the time they operate independently
of each other, which means the rear ABS being activated has no effect on the front wheel,
front ABS being activated has no effect on the rear wheel. The biggest connection you will get
is if there is real lift off mitigation, in which case, if the rear wheel comes off the
ground and the system senses it, it will release pressure in the front even if the front wheel
is nowhere close to lockup. But the thing you need to understand about fundamental difference
between car ABS and motorcycle ABS is that on a car, it's designed for an idiot who's driving.
I was at a Audi training school where the ABS test was very, very simple. The instructor says,
I want to see your knee when I'm standing outside the driver's door, that's how high you
will lift your foot and you'll hit that pedal with everything you've got and then the ABS system in
the car will do all of the work. On a motorcycle, if you were to do the exact same thing, which
is grab the lever like this, is that the brakes will come on strong and lock-up the wheel very,
very early on before the weight transfer can generate more grip and that's why on a motorcycle,
using ABS does require a little bit more skill. Honestly, it is a negative in terms
of how much work you have to put in to get ABS to do the maximum possible job for you,
but to me, motorcycles are about skilled people doing skilled things and to me this is exactly how
it's supposed to be. So braking on motorcycles, it's not the simplest thing in the world.
Using ABS at maximum efficiency on a motorcycle is not also the simplest thing in the world but
the whole pleasure of motorcycling is that we get to learn new things every day.
The final thing I would submit is that a lot of people are worried that electronic
interventions like ABS can destroy your experience of motorcycling and I would say that's just not true.
ABS, traction control, all of these systems only appear on the scene as visible partners in crime
when you've reached the limit of something and if something is not done to prevent what happens
next, you will get hurt or your motorcycle will be broken or both. So if you ride an ABS motorcycle
normally and have an uneventful ride, you will not be aware that ABS is working, but, if you were
riding the motorcycle normally and hit a patch of sand, you're on the brakes, ABS will allow you to
get through the patch of sand without having a crash, without ABS you would have a crash. The
last thing, professional riders under controlled conditions like near perfect weather, clean roads,
great tyres, in those conditions can sometimes outperform ABS and that's a big statement to
make because it's sometimes outperformed which means for most of us, ABS will help us a lot
more than get in our way. Thank you so much for watching, this is Simplified, we take complicated
automotive ideas, break them down into small pieces that you can use in your motorcycle life.
If you'd like to discuss braking and ABS in more detail, all you have to do is leave us a comment.
If you'd like any other topic, just leave us a comment, we'll get right on it. Thank you so much
for watching. Please do hit subscribe and the bell notification icon, if you loved this video, hit
the like button and please do show this to your friends, I think they will find it useful.