2008 PORSCHE CAYENNE brake pads

by a tandem booster and large
brake master cylinder. The foot-
operated parking brake uses a
duo-servo system mounted on
each of the rear discs.
Porsche Stability Management
(PSM) features two additional
brake functions: electronic brake
Porsche braking systems are
renowned worldwide as the
benchmark in performance and
stability. The Cayenne models
continue this tradition, offering
excellent deceleration – even
when fully laden with five adult
Porsche has always been synonymous with acceleration.
That’s only half the story.
Braking system.
All Cayenne models have internally
vented discs all round. This simple
yet highly effective design ensures
consistent brake performance.
The front disc dimensions
(diameter/thickness) are 330 mm /
32 mm on the Cayenne, 350 mm /
34 mm on the Cayenne S and
Cayenne GTS, and 380 mm /
38 mm on the Cayenne Turbo.
All models have six-piston monobloc
aluminium brake calipers at the
front and four-piston equivalents
at the rear. The Cayenne Turbo
has a new and more powerful
braking system to offset its higher
performance. The fixed calipers on
the Cayenne Turbo are noticeably
larger and have a striking red
paint finish. The calipers on the
Cayenne GTS are also red, while
the Cayenne S has silver and the
Cayenne black. Braking is assisted
Safety
occupants, a full complement of
luggage and a braked trailer load
of up to 3,500 kg (Cayenne GTS
with steel-sprung suspension:
3,080 kg).
prefill prior to an emergency stop
and all-wheel brake assist. See
page 98 for more information
on PSM.
All brake pads are fitted with
individual wear sensors. When new
pads are required, a warning light
is illuminated in the instrumentcluster. The brake lines serving
each of the rear calipers feature
special off-road protection
against rocks and other debris.
· 95 · · 94 · Cayenne: standard front brake
with 330-mm discCayenne S: standard front brake
with 350-mm disc
Cayenne GTS: standard front brake
with 350-mm discCayenne Turbo: new standard front brake
with 380-mm disc

piston units at the rear. The
resulting brake forces are not
only high, they are also extremely
Porsche Ceramic Composite Brake (PCCB).
Porsche Ceramic Composite Brake (PCCB),
front disc diameter: 410 mm
The pads are mounted in six-
piston monobloc aluminium fixed
calipers at the front, with four-
Safety
As an optional alternative, the
Cayenne S, Cayenne GTS and
Cayenne Turbo can all be
equipped with the race-proven
Porsche Ceramic Composite
Brake (PCCB)*.
The large disc diameter (410 mm
front and 370 mm rear) adds
significantly to brake performance.
The discs are made from a
specially treated carbon-fibre
compound that is silicated in a
high-vacuum process at 1,700 ºC.
The resulting material is not only
much harder than cast iron, it
is also more resistant to heat.
Even at high temperatures, the
thermal resistance of the PCCB
disc ensures excellent dimensional
stability. The ceramic material is
totally resistant to corrosion and
offers excellent acoustic damping
properties.consistent. The pedal response
is fast and precise with only
moderate input required.
PCCB enables shorter braking
distances in even the toughest
road and race conditions.
Excellent fade resistance ensures
greater balance when slowing
from high speed.
· 97 · · 96 ·
The Porsche Ceramic Composite
Brake (PCCB) is a visible
acknowledgement of Porsche race
engineering. The key advantage
is a total weight saving of
approximately 50 % compared
with equivalent cast-iron discs.
As well as enhancing performance,
the unsprung and rotating masses
are lightened. The results: greater
comfort and road-holding
on uneven road surfaces plus
better handling and agility.
* Compatible with 20-inch wheel diameter or greater as well as 19-inch collapsible spare wheel.

Oversteer with PSM
Understeer without PSM
Car steers
off line Car steers
off line PSM corrects
line and
stabilises car
PSM corrects
line and
stabilises car
Understeer with PSM Oversteer without PSM
All Cayenne models are
equipped with Porsche Stability
Management (PSM) as standard.
This electronic control system
uses a range of functions –
including anti-lock braking (ABS) –
to help stabilise the vehicle
(and trailer, if fitted) in hazardous
road scenarios. Throughout each
journey, PSM uses a range of
sensors to monitor the direction,
speed, yaw velocity (speed of
rotation around the vertical axis)
and lateral acceleration of the
car. The system then calculates
the actual direction of travel. If
the car begins to oversteer or
understeer, PSM applies selective
braking on individual wheels to
restore stability. If necessary,
PSM can also intervene in the
engine management system to
temporarily modify the amount
of drive to the wheels.PSM has two additional functions
that help reduce braking distances.
If the throttle pedal is released
suddenly, PSM automatically
readies the braking system. The
pressure in the brake lines is
marginally increased, bringing
each of the pads into light contact
with the corresponding disc. If the
driver goes on to apply the brakes,
the calipers respond more quickly.
In an emergency stop – i.e., when
the pressure on the brake pedal
exceeds a certain threshold –
the brake assist function uses
the PSM hydraulics to apply
maximum braking force at all
four wheels.
PSM makes a significant contribu-
tion to car and trailer safety –
within the laws of physics. It
compensates for load transfer
caused by throttle and brake
inputs up to the maximum degree
of lateral acceleration. It also
enhances the car’s driving dynam-
ics and directional stability when
accelerating on variable road
surfaces. PSM can also intervene
through the locking centre and
axle differentials as part of
Porsche Traction Management
(PTM).
Other features include a
special control strategy in
the PSM-integrated ABS for braking on loose surfaces such
as gravel or snow. By briefly
locking the wheels, a wedge is
formed ahead of each tyre which
provides additional purchase
to help slow the car.
For a more active driving experi-
ence, PSM can also be disabled.
For safety reasons, it remains
active in the background, ready
to intervene in critical scenarios.
Expecting the best means preparing for the worst.
Porsche Stability Management (PSM).
Safety
· 99 · · 98 ·