Integrated Braking
If,
when you apply your rear brake, your motorcycle also applies front
braking for you, then you have some form of 'integrated braking.' In
the case of the Honda GoldWing, there are two front disc brakes and
one rear disc brake. One of the front brakes is independently
controlled by the front brake lever while the other front brake and
the rear brake are both activated by the rear brake pedal.
Some
people do not understand why integrated braking exists and are of the
opinion that they are unsafe. There are some who actually disable (or
want to) this function and tie the two front brakes together so that
they are both activated at the same time and exclusively by the front
brake lever.
The
reason they do this is NOT in order to increase the amount of braking
force they can employ on the front wheel, but in order to prevent
using any front brake force at all under certain braking conditions.
In other words, they want the ability to selectively use either their
front or rear brakes, or both. This, because they fear that integrated
braking increases the odds that on slippery roadways they will lock
the front wheel with the resulting dumping of their bike.
This is
a common concern by those that have had no experience with integrated
braking systems, but is, in my opinion, an exaggerated concern.
Let's
get something out of the way right up front - there is NEVER a time to
aggressively use your REAR brake. IT is the most dangerous control on
your motorcycle because it is so easy to abuse.
Under
severe braking weight transfer results in far more load on the front
tire than on the rear one. What that means is that it takes far less
braking force to lock the rear wheel. Let's say, for arguments sake,
that 70 percent of the bike's weight is on the front tire and 30
percent on the back one during a severe braking event,
and let's also assume that your bike weights 1,000 pounds with you on
it. In this case if you applied about 300 pounds of braking force to
the rear wheel it would be close to sliding.
Your
integrated braking system (at least in the case of a GoldWing) is
setup up such that when you apply 300 pounds to the rear brake
something between 200 and 250 pounds of braking force is applied to
one of your front brakes. (This is because the size of the piston in
the integrated front brake is smaller than the piston in either of the
other two brakes as well as the pistons in the master cylinders.)
Since there is 700 pounds of load on the front tire, it is clear that
the integrated braking system cannot cause the front wheel to lock by
itself. On the other hand, if you didn't use the front brake lever at
all in this condition, you have applied only a total of less than 550
pounds of braking force (300 + upto 250) and that is not enough to
have caused a weight shift resulting in 70% being on the front tire.
In other words, you had to use the front brake as well in order to be
in a 'severe braking' condition.
Let me
review for a second: Braking causes a weight transfer towards the
front. If you do not lock the rear brake, you CANNOT lock the front
brake unless you also aggressively use the front brake lever. So, if
you lock the front wheel you do so with the front brake lever, not the
rear one.
If you
agree that it is NEVER appropriate to aggressively use the rear brake,
it becomes only marginally important when stopping aggressively. (Though
that margin could be the difference between life and death.)
So,
integrated braking should be viewed as providing an added safety
margin when you need to stop aggressively. Whether the surface is dry
or wet, the relationship between the two integrated brakes is the same
and what has been said so far remains true.
What
if, however, you overuse the front brake while using less rear brake
than would cause the rear wheel to lock? Then it is entirely possible
to lock the front wheel. This possibility is apparently what concerns
inexperienced users the most.
I
assume, because virtually all motorcycle riders know better, that you
do not employ 'severe braking' while your bike is leaned over in a
curve. That is, you straighten the bike up before you grab the
binders. If that is the case, then what is the consequence of locking
the front brake? A slide that you can abort by simply releasing some
of the front brake pressure.
Since
your SPINNING rear wheel provides gyroscopic stability for the
majority of your motorcycle, (meaning you have not locked the rear
wheel, just the front one), then your sliding front tire will not
immediately dump you to the ground as it would if it were sliding in a
turn. In other words, you have time to release the front brake to
recover.
Most
people, once they learn that the rear brake must never be used
aggressively, are far better off having integrated braking than not
because of the marginal increase in stopping power it provides.
But
there is a time when they can get in the way. If you are driving at
slow speeds on slippery surfaces (such as on a gravel covered parking
lot), then the combination of both front brakes being used can cause
the front wheel to lock easily. That is, since we are not talking
about 'severe braking', then there is minimal weight on the front tire
at this time and it is easier to lock that wheel.
If
going in a straight line you can save the situation by simply
releasing the front brake, just as before. But when you are driving on
a parking lot it is not unthinkable that you are making a turn or two,
and if you lock that front wheel when it is not dead center, you will
dump the bike.
So,
should you disconnect the integrated brakes to prevent a parking lot
dump? NO! Just don't use your front brake lever in this case. As we
discussed, your rear brake lever always applies more braking force to
your rear brake than it does to the integrated front brake. If you do
not lock the rear wheel with it, you will not lock the front wheel
either.
Finally,
it is NOT true that just because you have integrated braking it is
impossible to apply rear-wheel braking without getting some
front-wheel braking. How so? Just use engine braking rather than your
rear-brake pedal.
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