2008 MERCEDES-BENZ CLK550 weight

358 Operation
Tires and wheels
Tire and loading terminology
Accessory weight
The combined weight (in excess of those
standard items which may be replaced) of
automatic transmission, power steering,
power brakes, power windows, power
seats, radio, and heater, to the extent that
these items are available as
factory-installed equipment (whether
installed or not).
Air pressure
The amount of air inside the tire pressing
outward on each square inch of the tire.
Air pressure is expressed in pounds per
square inch (psi), or kilopascal (kPa) or
bars.
Aspect ratio
Dimensional relationship between tire
section height and section width
expressed in percentage.Bar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi)
to 1 bar; there are 100 kilopascals (kPa)
to 1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least 3 hours or
driven no more than 1 mile (1.6 km).
Curb weight
The weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if so
equipped, air conditioning and additional
optional equipment, but without passen-
gers and cargo.DOT (Department of Transportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross Axle Weight Rating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
certification label located on the driver’s
door B-pillar.
GVW (G
ross Vehicle Weight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GVW must never exceed the
GVWR indicated on the certification label
located on the driver’s door B-pillar.

359 Operation
Tires and wheels
GVWR (Gross Vehicle Weight Rating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
certification label located on the driver’s
door B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are 100 kilopascals
(kPa) to 1 bar.
Maximum load rating
The maximum load in kilograms and
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
total load limit and production options
weight.Maximum tire inflation pressure
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lbs).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.
Production options weight
The combined weight of those installed
regular production options weighing over
5 lbs (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.PSI (Pounds per square inch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
The recommended tire inflation pressure is
listed on Tire and Loading Information
placard located on driver’s door B-pillar for
normal driving conditions and provides
best handling, tread life and riding com-
fort. If so equipped, supplemental informa-
tion pertaining to special driving situations
can be found on the tire inflation pressure
label on the inside of the fuel filler flap.
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated.
Sidewall
The portion of a tire between the tread and
the bead.

360 Operation
Tires and wheels
TIN (Tire Identification Number)
Unique identifier which facilitates efforts
by tire manufacturers to notify purchasers
in recall situations or other safety matters
concerning tires and gives purchases the
means to easily identify such tires. The TIN
is comprised of “Manufacturer’s identifica-
tion mark”, “Tire size”, “Tire type code”
and “Date of manufacture”.
Tire load rating
Numerical code associated with the
maximum load a tire can support.
Tire ply composition and material used
This indicates the number of plies or the
number of layers of rubber-coated fabric in
the tire tread and sidewall. Tire manufac-
turers also must indicate the ply materials
in the tire and sidewall, which include
steel, nylon, polyester, and others.Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is approved.
Total load limit
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle’s
designated seating capacity.
Traction
Force exerted by the vehicle on the road
via the tires. The amount of grip provided.
Tread
The portion of a tire that comes into
contact with the road.
Treadwear indicators
Narrow bands, sometimes called
“wear bars” that show across the tread of
a tire when only
1/16in (1.6 mm) of tread
remains.Uniform Tire Quality Grading Standards
A tire information system that provides
consumers with ratings for a tire's traction,
temperature and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The
ratings are molded into the sidewall of the
tire.
Vehicle maximum load on the tire
Load on an individual tire that is
determined by distributing to each axle its
share of the maximum loaded vehicle
weight and dividing it by two.

390 Practical hints
What to do if …?
Lamp in center console
ProblemPossible cause/consequenceSuggested solution
56The front passenger front air bag
off indicator lamp illuminates
and remains illuminated with the
weight of a typical adult or some-
one larger than a small individual
on the front passenger seat.The system is malfunctioning.Have the system checked as soon as
possible at an authorized
Mercedes-Benz Center.
Read and observe messages in the
multifunction display and follow cor-
rective steps (
page 396).
Warning!G
If the 56 indicator lamp illuminates
and remains illuminated with the weight of a
typical adult or someone larger than a small
individual on the front passenger seat, do
not have any passenger use the front
passenger seat until the system has been
repaired.

391 Practical hints
What to do if …?
ProblemPossible cause/consequenceSuggested solution
56The front passenger front air bag
off indicator lamp does not illu-
minate and/or does not remain
illuminated with the weight of a
typical 12-month-old child in a
standard child restraint or less
on the front passenger seat.The system is malfunctioning.Make sure there is nothing between
seat cushion and child seat and check
installation of the child seat.
Make sure no objects applying sup-
plemental weight onto the seat are
present.
If the front passenger front air bag off
indicator lamp remains out, have the
system checked as soon as possible
at an authorized Mercedes-Benz
Center. Do not transport a child on
the front passenger seat until the sys-
tem has been repaired.
Read and observe messages in the
multifunction display and follow cor-
rective steps (
page 396).
Warning!G
If the 56 indicator lamp does not
illuminate or remains out with the
weight of a typical 12-month-old child in a
standard child restraint or less on the front
passenger seat, do not transport a child on
the front passenger seat until the system
has been repaired.

396 Practical hints
What to do if …?
Display messagePossible cause/consequencePossible solution
Front Passenger
Airbag Enabled
See Operator’s ManualFront passenger front air bag is
activated while driving even though
a child, small individual, or object
below the system’s weight
threshold is on the front passenger
seat, or the front passenger seat is
empty. Objects on the seat or
forces acting on the seat may
make the system sense supple-
mental weight.Stop the vehicle in a safe location as soon as possible and check the
front passenger seat for the following:
Switch off the ignition (page 38).
Remove child and child restraint from front passenger seat and
properly secure the child in rear seat employing the child restraint
if necessary.
Make sure no objects applying supplemental weight onto the seat
are present. The system may recognize such supplemental weight
and sense that an occupant on the front passenger seat is of a
greater weight than actually present.
Keep the seat unoccupied, close the front passenger door and
switch on the ignition (
page 38).
(Continued on next page)

398 Practical hints
What to do if …?
Display messagePossible cause/consequencePossible solution
Front Passenger
Airbag Disabled
See Operator’s ManualFront passenger front air bag is
deactivated while driving even
though an adult or someone larger
than a small individual is
occupying the front passenger
seat. Forces acting on the seat
may make the system sense a
decrease in weight.Stop the vehicle in a safe location as soon as possible and check the
front passenger seat for the following:
Switch off the ignition (page 38).
Have the front passenger vacate the seat and exit the vehicle.
Keep the seat unoccupied, close the front passenger door and
switch on the ignition (
page 38).
(Continued on next page)

431 Practical hints
Opening/closing in an emergency (Cabriolet)
Insert long side of hex wrench2 into
opening.
Using hex wrench 2, press release
catch down in direction of arrow.
The roll bar extends with a loud sound.
Repeat this step for the second roll bar.
Have the systems checked at an autho-
rized Mercedes-Benz Center as soon as
possible.
Lowering roll bars manually
With the soft top open, you can lower the
roll bars manually after they have been re-
leased.
1Orientation seam
2Hex wrench
3Press wrench down
4Press head restraint down
Take hex wrench out of its storage
location in the storage well casing
(
page 422).
Align hex wrench so that its long side is
parallel to orientation seam1 and in-
sert hex wrench2 into gap on left side
of respective head restraint.
Press hex wrench down firmly in direc-
tion of arrow3 and hold.
Press head restraint down in direction
of arrow4.
Pull hex wrench 2 out and take weight
off head restraint.
Repeat this procedure on roll bar for
second head restraint.
iWith the roll bars released, the soft top can-
not be operated using the soft top switch and the
rear head restraints cannot be lowered using the
rear head restraint lowering switch.
Warning!G
Never lower the roll bars manually unless
the soft top is open. Otherwise, the roll bars
function could be impaired, no longer reduc-
ing your risk of injury in an optimal manner.
Contact an authorized Mercedes-Benz Cen-
ter to have the roll bar lowered when the
soft top is closed.