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NEW BREMBO
19 RCS RADIAL
BRAKE MASTER CYLINDER
The Brembo radial master cylinder has
effectively revolutionized motorcycle braking systems over
the past ten years. Designed originally for use on Racing
machines, it has become more and more popular over time
for Super Sport, and even Naked bikes, while retaining the
identity of an out-and-out racing component, still used
today in MotoGP competition.
Today, bike enthusiasts everywhere can
upgrade the braking system on their machines at a stroke,
simply by replacing the production master cylinder with
a Brembo radial, confident of the top-flight performance
associated with many years experience acquired by the company
in designing and engineering braking systems.
Why "radial"? The definition
indicates a configuration whereby force can be transmitted
to the piston "in phase" with the force applied
by hand to the lever, eliminating the friction that would
be generated if these forces were separated. In other words,
the effort exerted by hand on the lever and the force applied
by the lever to the piston are both generated in the same
direction - radially - relative to the point where the cylinder
is anchored, i.e. the handlebar. With this type of construction,
the master cylinder can be designed with the focus on optimizing
hydraulic and mechanical ratios, and consequently on improving
its performance. This means that the force applied to the
lever can be converted entirely into powerful, dependable
and precise braking action.
For twin-disc systems; there are currently
two models of Brembo radial master cylinder available: 19x18
and 19x20. The choice between the two models will be based
essentially on the feel that the rider is able to get from
the two solutions.
The 19x18 cylinder has better modulation,
given its marginally longer operating travel when compared
to the 19x20, which on the other hand offers a slightly
quicker response.
As a general rule, the 19x18 is recommended for bikes with
4-piston calipers (diameters 32/36, 34/34 and 30/34), whereas
the 19x20 is more suitable for other calipers.
Brembo experience favours 19x18 for track,
and 19x20 for street.
Today, after 10 years as a brand leader,
this legendary product has been updated with a number of
significant new engineering features, all derived from MotoGP,
and is now marketed as the new Racing radial brake master
cylinder.
::::: TECHNICAL DATA SHEET
:::::
 The
new Brembo 19 RCS radial brake master cylinder retains the
familiar geometry, dimensions and functionality of the MotoGP
component, while introducing many engineering improvements.
 Adjustable
pivot distance: RCS system
With this new patented device, the rider
can set the brake lever pivot point at one of two distances,
18 or 20 mm, simply by turning a roller cam located on the
front of the lever clevis.
With the RCS - Ratio Click System - the
change from one setting to another is simplicity itself,
and the lever ratio can be adapted to the different characteristics
of the braking system, the ride or the conditions: for example,
dry or wet, road surfaces offering greater or lesser degrees
of grip, riding style, and so on…
The red colour of the cam indicates pivot
distance 18mm (FIG. C1), whereas the black colour indicates
the 20mm position (FIG. C2)
This is a feature that was until now
unavailable, but now provides the adjustment that will give
the optimum feel between rider, riding style, machine and
circuit.
MOTO GP piston assembly
The piston, seals and push-rod are the
same as those of master cylinders used by all riders in
MotoGP and Superbike competition.
In practice, MotoGP and Superbike provide
the ultimate test-bed for these components, given the enormous
stresses involved: late and hard braking, ultra-high disc
temperatures... under these conditions, the rider must be
able to rely on supreme dependability and unwavering efficiency
of the braking system.
The master cylinder plays a key role
in the braking action, and with a MotoGP piston assembly
fitted, top performance will be guaranteed whatever the
conditions, thanks to the extremely close machining tolerances
adopted, and a faultless sliding action within the cylinder
body.
Master cylinder body
The body of the master cylinder is an aluminium alloy forging*,
machined on CNC (Computer Numerical Control) equipment and
weight-relieved by milling. Machining tolerances are extremely
close - the same as adopted for MotoGP specification - so
as to guarantee a perfect match with the piston, and unparalleled
stroking precision.
The finish selected for the surface is hard anodization,
an electrochemical process by which the surface of the aluminium
and its alloys is converted into a layer of ultra-hard oxide.
This durable film affords especially high resistance to
abrasion and corrosion.
* The forging process involves preheating
a cylindrical metal billet to a high temperature - short
of melting point, so that it remains solid - then, using
a press of several tonnes capacity, driving the hot metal
into a die that presents the negative shape of the finished
item.
The main characteristic of a forged
piece derives from the way the fibres of the material are
oriented, and the influence this has on the mechanical properties
of the component. Forging has the effect of orienting the
fibres along lines parallel to the outer surfaces, a structural
attribute that improves resistance to fatigue. Accordingly,
the design of the die is fundamental, in that it must emulate
the finished item. The smaller the differences between blank
and finished part, the better the advantages of forging
will be exploited.
Brake lever
The brake lever is made up of two main components: the Racing
Lever Clevis, and the lever itself, forged and hinged to
the clevis.
The clevis incorporates a patent system
allowing angular movement only in the event that the bike
should happen to fall or crash. This prevents the lever
from rotating accidentally, and provides increased dynamic
safety.
The lever span adjustment control has
been repositioned and is now aligned with the lever, so
that the adjuster can also be located remotely.
 Operating
this control, the position of the lever contact face remains
unchanged relative to the cylinder body, so that the optimum
operating angle ß of the push rod can be maintained
(see fig E). This means that the lever can be drawn closer
to or distanced from the handlebar without any adverse effect
on the mechanism, guaranteeing minimal friction and zero
waste of energy. The technology is the same as adopted in
MotoGP.
In addition, the lever is hinged to the
cylinder body by way of a precision pin and bush assembly,
guaranteeing optimum rigidity, better feel and especially
high resistance to wear.
 Lever
return springs
Two high load springs are used to ensure that the contact
face and push-rod remain permanently engaged. This avoids
the eventuality of wear through chatter that could be induced
by vibrations from the machine, as well as introducing a
further element of safety during the transition from throttle
to brake, and generally prolonging the life of the various
components.
Brake light switch
A housing has been included specifically to accept the mechanical
switch of a brake light circuit, when the 19 RCS is set
up for street use.
Clutch master cylinder
The 16RCS clutch master cylinder makes up a set with the
19RCS.
The 16RCS is equipped similarly with
the Ratio Click System, allowing adjustment of the feel
on clutch control. Like the 19RCS brake master cylinder,
this component has a forged aluminium alloy body with hard-anodized
surface finish.
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