325 Operation
Tires and wheels
Always follow the recommended tire
inflation pressure (
page 312) for proper
tire inflation. Uniform Tire Quality Grading Standards (U.S. vehicles)
Tire manufacturers are required to grade
tires based on three performance
factors: treadwear, traction and
temperature resistance.
1Treadwear
2Traction
3Temperature resistanceQuality grades can be found, where appli-
cable, on the tire sidewall between tread
shoulder and maximum section width. For
example:
All passenger car tires must conform to
federal safety requirements in addition to
these grades.
Warning!G
Never exceed the max. tire inflation
pressure. Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly,
adversely affect handling and fuel economy,
and are more likely to fail from being over-
heated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride
comfort, wear unevenly, increase stopping
distance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road
debris, potholes etc.
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.
TreadwearTractionTemperature
200AAA
328 Operation
Tires and wheels
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 three 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 GWV must never exceed the
GWVR indicated on the certification label
located on the driver’s door B-pillar.GVWR (G
ross 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.
329 Operation
Tires and wheels
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
Recommended tire inflation pressure for
normal driving conditions is listed on the
Tire and Loading Information placard locat-
ed on the driver’s door B-pillar. 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.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.
331 Operation
Tires and wheels
If applicable to your vehicle’s tire configu-
ration, tires can be rotated according to
the tire manufacturer’s recommended in-
tervals in the tire manufacturer’s warranty
pamphlet located in your vehicle literature
portfolio. If none is available, tires should
be rotated every 3 000 to 6 000 miles
(5 000 to 10 000 km), or sooner if neces-
sary, according to the degree of tire wear.
The same rotation (spinning) direction
must be maintained (
page 307).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
Thoroughly clean the mounting face of
wheels and brake discs, i.e. the inner side
of the wheels/tires, during each rotation.
Check for and ensure proper tire inflation
pressure.For information on wheel change, see the
“Practical hints” section (
page 385) and
(
page 401).
Warning!G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
80 lb-ft (110 Nm).
Only use genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.
365 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Run Flat
IndicatorinoperativeThe Run Flat Indicator* is malfunc-
tioning.Have the Run Flat Indicator* checked by an
authorized Mercedes-Benz Center.
The Run Flat Indicator* has been
switched off due to a malfunction.
Tire pressureCheck tiresThe Run Flat Indicator* indicates
that the pressure is too low in one or
more tires.Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers. Observe
the traffic situation around you.
Check and adjust the tire inflation pressure as
required (
page 314).
If necessary, change the wheel (page 401).
Restart the Run Flat Indicator* after adjusting the
tire inflation pressure values (
page 314).
Check tiresThen restart
Run Flat IndicatorThere was a warning message about
a loss in tire inflation pressure and
the Run Flat Indicator* has not been
restarted yet.Make sure that the correct tire inflation pressure
is set for each tire.
Then restart the Run Flat Indicator*
(
page 316).
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause exces-
sive heat build-up and possibly a fire.
401 Practical hints
Flat tire
Flat tire
The SLK 55 AMG with Performance
Package* is equipped with a TIREFIT kit.
Preparing the vehicle
Park the vehicle in a safe distance from
moving traffic on a hard, flat surface
when possible.
Turn on the hazard warning flashers.
Turn the steering wheel so that the
front wheels are in a straight ahead
position.
Set the parking brake (page 53).
Move the gear selector lever* toP
(manual transmission to first or reverse
gear).
Turn off the engine (page 61).
Remove the SmartKey from the starter
switch.
Have any passenger exit the vehicle at
a safe distance from the roadway.
Sealing tires with TIREFIT
Small tire punctures, particularly those in
the tread, can be sealed with TIREFIT.
TIREFIT can be used in ambient tempera-
tures down to -4°F (-20°C).
Foreign objects (e.g. screws or nails)
should not be removed from the tire.
Take TIREFIT, the sticker, and the
electric air pump out of the trunk
(
page 382).
iOpen door only when conditions are safe to
do so.
iSLK 55 AMG with Performance Package*
only.
Warning!G
Keep TIREFIT away from sparks, open flame
or heat source.
Do not smoke.
Warning!G
TIREFIT is a limited repair device. TIREFIT
cannot be used for cuts or punctures larger
than approximately 0.16 in (4 mm) and tire
damage caused by driving with extremely
low tire inflation pressure, or on a flat tire, or
a damaged wheel.
Do not drive the vehicle under such circum-
stances.
Contact the nearest Mercedes-Benz Center
for assistance or call Roadside Assistance.
404 Practical hints
Flat tire
Version 1
aVent screw
bPressure gauge
Close vent screwa on pressure
gaugeb (version 1 only).
Screw filler hose8 onto tire valve9
(
page 403).
Insert electrical plug4 (page 403)
into the cigarette lighter (
page 256).
Turn the SmartKey in the starter switch
to position1 (
page 37).
PressI on electric air pump switch3
(
page 403).
The electric air pump is switched on
and inflates the tire.
Let the electric air pump inflate the tire
for approximately 5 minutes.
The pressure gauge must display at
least 26 psi (1.8 bar). The air hose can
become hot during inflation.
Please exercise appropriate caution.
If the tire inflation pressure of at least
26 psi (1.8 bar) is not attained, turn off
the electric air pump by pressing0 on
electric air pump switch3
(
page 403).
Detach filler hose8 f r o m t i r e v a l v e9
(
page 403).
Drive vehicle back and forth very slowly
approximately 30 ft (10 m).
This serves to better distribute the
TIREFIT sealant material inside the tire.
Unscrew the air pump’s air hose5
from flange6 of TIREFIT container1
(
page 403).
Screw air hose5onto tire valve9.
Inflate the tire again.
iFirst, the sealing is pumped into the tire. The
pressure may briefly rise to up to 73 psi (5 bar).
This is normal and not an indication of a malfunc-
tion. Do not switch off the electric air pump.
!Do not operate the electric air pump longer
than 6 minutes without interruption. Otherwise it
may overheat.
You may operate the air pump again after it has
cooled off.
405 Practical hints
Flat tire
After attaining a tire inflation pressure
of 26 psi (1.8 bar), press0 on electric
air pump switch8 (
page 403).
The electric air pump is switched off.
Turn the SmartKey in the starter switch
to position0 (
page 37).
Detach the electric air pump.
The air hose may still be hot. Please
exercise appropriate caution.
Place the electrical air pump back in
the trunk.
Close the trunk lid.
Drive off immediately.
The TIREFIT sealant will distribute itself
evenly inside the tire.
After driving the vehicle for an initial
10 minutes, check the tire inflation
pressure using pressure gauge 9 on
the air pump.
Warning!G
If a tire inflation pressure of 26 psi (1.8 bar)
is not attained, the tire is too severely
damaged for TIREFIT to provide a reliable
tire repair.
In this case, TIREFIT cannot properly seal
the tire.
Do not drive the vehicle.
Contact the nearest Mercedes-Benz Center
or call Roadside Assistance.
Warning!G
Do not exceed vehicle speed of
50 mph (80 km/h). A TIREFIT repair is not
designed to operate at higher speeds.
The sticker must be attached on the instru-
ment cluster where it will be easily seen by
the driver.
Vehicle handling characteristics may
change. Adapt your driving accordingly.
Warning!G
If tire inflation pressure has fallen below
20 psi (1.3 bar) do not continue to drive the
vehicle.
Park your vehicle safely away from the road-
way and contact the nearest authorized
Mercedes-Benz Center or Roadside
Assistance.
Have the damaged tire replaced.