2018 MERCEDES-BENZ SL ROADSTER Owner's Manual

MOExtended tires (tires with run-flat
characteristics)
With MOExtended tires (tires with run flat char-
acteristics), you can continue to drive your vehi-
cle even if there is a total loss of pressure in one
or more tires.
MOExtended tires may only be used in conjunc-
tion with an active tire pressure monitor and
only on wheels specifically tested by Mercedes- Benz.
Notes on driving with MOExtended tires with a
flat tire (
Ypage 271).
Vehicles equipped with MOExtended tires are
not equipped with a TIREFIT kit at the factory. It
is therefore recommended that you additionally
equip your vehicle with a TIREFIT kit if you mount
tires that do not feature run-flat characteristics,
e.g. winter tires. A TIREFIT kit can be obtained
from a qualified specialist workshop.
Winter operation
General notes
Have your vehicle winter-proofed at a qualified
specialist workshop at the onset of winter.
Observe the notes in the "Changing a wheel"
section (
Ypage 304).
Driving with summer tires
At temperatures below 45 ‡ (+7 †), summer
tires lose elasticity and therefore traction and
braking power. Change the tires on your vehicle
to M+S tires. Using summer tires at very cold
temperatures could cause cracks to form,
thereby damaging the tires permanently.
Mercedes-Benz cannot accept responsibility for
this type of damage.
GWARNING
Damaged tires can cause tire inflation pres-
sure loss. As a result, you could lose control of
your vehicle. There is a risk of accident.
Check the tires regularly for signs of damage
and replace any damaged tires immediately.
M+S tires
GWARNING
M+S tires with a tire tread depth of less than
ã in (4 mm) are not suitable for use in winter
and do not provide sufficient traction. There is
a risk of an accident.
M+S tires with a tread depth of less than ãin
(4 mm) must be replaced immediately.
At temperatures below 45 ‡(+7 †), use winter
tires or all-season tires. Both types of tire are
identified by the M+S marking.
Only winter tires bearing the isnowflake
symbol in addition to the M+S marking provide
the best possible grip in wintry road conditions.
Only these tires will allow driving safety systems
such as ABS and ESP
®to function optimally in
winter. These tires have been developed specif-
ically for driving in snow.
Use M+S tires of the same make and tread on all
wheels to maintain safe handling characteris-
tics.
Always observe the maximum permissible
speed specified for the M+S tires you have
mounted.
When you have mounted the M+S tires:
XCheck the tire pressures (Ypage 291).
XRestart the tire pressure monitor
(Ypage 293).
Snow chains
GWARNING
If snow chains are installed to the front
wheels, they may drag against the vehicle
body or chassis components. This could
cause damage to the vehicle or the tires.
There is a risk of an accident.
To avoid hazardous situations:
Rnever install snow chains to the front
wheels
Ralways install snow chains in pairs to the
rear wheels.
For safety reasons, Mercedes-Benz recom-
mends that you only use snow chains that have
been specially approved for your vehicle by
Winter operation287
Wheels and tires
Z

Mercedes-Benz, or are of a corresponding
standard of quality. For more information,
please contact a qualified specialist workshop.
If you intend to mount snow chains, please bear
the following points in mind:
RSnow chains may not be mounted on all
wheel/tire combinations. Permissible wheel-
tire combinations (
Ypage 308).
ROnly use snow chains when driving on roads
completely covered by snow. Remove the
snow chains as soon as possible when you
come to a road that is not snow-covered.
RLocal regulations may restrict the use of snow
chains. Observe the appropriate regulations if
you wish to mount snow chains.
RDo not exceed the maximum permissible
speed of 30 mph (50 km/h).
ROn vehicles with Active Body Control (ABC), if
snow chains have been installed, you must
drive at a raised vehicle level (
Ypage 163).
You may wish to deactivate ESP®when pulling
away with snow chains installed (Ypage 65).
You can thereby allow the wheels to spin in a
controlled manner, achieving an increased driv- ing force (cutting action).
Tire pressure
Tire pressure specifications
Important safety notes
GWARNING
Underinflated or overinflated tires pose the
following risks:
Rthe tires may burst, especially as the load
and vehicle speed increase.
Rthe tires may wear excessively and/or
unevenly, which may greatly impair tire
traction.
Rthe driving characteristics, as well as steer-
ing and braking, may be greatly impaired.
There is a risk of an accident.
Follow recommended tire inflation pressures
and check the pressure of all the tires includ-
ing the spare wheel:
Rmonthly, at least
Rif the load changes
Rbefore beginning a long journey
Runder different operating conditions, e.g.
off-road driving
If necessary, correct the tire pressure.
The data on the Tire and Loading Information
placard and tire pressure table shown here are
examples. Tire pressure specifications are vehi-
cle-specific and may deviate from the data
shown here. The tire pressure specifications
that are valid for your vehicle can be found on
the Tire and Loading Information placard and
tire pressure table on the vehicle.
General notes
The recommended tire pressures for the tires
mounted at the factory can be found on the
labels described here.
Further information on tire pressures can be
obtained at a qualified specialist workshop.
Tire and Loading Information placard
:Recommended tire pressures
The Tire and Loading Information placard is on
the B-pillar on the driver's side (
Ypage 295).
The Tire and Loading Information placard con-
tains the recommended tire pressures for cold
tires. The recommended tire pressures are valid
for the maximum permissible load and up to the
maximum permissible vehicle speed.
288Tire pressure
Wheels and tires

Tire pressure table
The tire pressure table is on the inside of the fuelfiller flap. It shows the tire pressure for all tires
permitted at the factory for this vehicle; see
illustration (example).
The tire pressure table contains the recommen-
ded pressures for cold tires for various operat-
ing conditions, i.e. differing load and speed con-
ditions.
If a tire size precedes a tire pressure, the fol-
lowing tire pressure information is only valid forthat tire size; see illustration (example).
The load conditions "partially laden" and "fully
laden" are defined in the table for different num-
bers of occupants and amounts of luggage. The
actual number of seats may differ.
Some tire pressure tables show only the rim
diameters instead of the full tire size, e.g. R18.
Rim diameter is part of the tire size and can be
found on the tire sidewall (
Ypage 298).
If the tire pressures have been set to the lower
values for lighter loads and/or lower road
speeds, the pressures should be reset to the
higher values:
Rif you want to drive with an increased load
and/or
Rif you want to drive at higher road speeds
The tire pressures for increased loads and/or
higher road speeds, shown in the tire pressure
table, may have a negative effect on driving
comfort.
If the tire pressure is not set correctly, this can
lead to an excessive build-up of heat and a sud-
den loss of pressure.
For more information, contact a qualified spe-
cialist workshop.
Important notes on tire pressure
GWARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
RCheck the tire for foreign objects.
RCheck whether the wheel is losing air or the valve is leaking.
If you are unable to rectify the damage, con-
tact a qualified specialist workshop.
GWARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded and
malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire pres- sure monitors keep the tire valve open. This
can also result in tire pressure loss. There is a
risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check the tire
pressure. The outer appearance of a tire does
Tire pressure289
Wheels and tires
Z

not permit any reliable conclusion about the tire
pressure. On vehicles equipped with the elec-
tronic tire pressure monitor, the tire pressure
can be checked in the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is dependent
on the driving speed and the load.
Therefore, you should only correct tire pres-
sures when the tires are cold.
The tires are cold:
Rif the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and
Rif the vehicle has not been driven further than
1 mile (1.6 km)
The tire temperature changes depending on the outside temperature, the vehicle speed and the
tire load. If the tire temperature changes by
18 ‡ (10 †), the tire pressure changes by
approximately 10 kPa (0.1 bar/1.5 psi). Take
this into account when checking the pressure of
warm tires. Only correct the tire pressure if it is
too low for the current operating conditions. If
you check the tire pressure when the tires are
warm, the resulting value will be higher than if
the tires were cold. This is normal. Do not
reduce the tire pressure to the value specified
for cold tires. The tire pressure would otherwise
be too low.
Observe the recommended tire pressures for
cold tires:
Ron the Tire and Loading Information placard
on the B-pillar on the driver's side
Rin the tire pressure table on the inside of the
fuel filler flap
Underinflated or overinflated tires
Underinflated tires
GWARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addition, they also suffer from excessive and/or irreg-
ular wear, which can severely impair the brak-
ing properties and the driving characteristics.
There is a risk of an accident.
Avoid tire pressures that are too low in all the
tires, including the spare wheel. Underinflated tires may:
Roverheat, leading to tire defects
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on fuel consumption
Overinflated tires
GWARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and the driving characteristics. There is a risk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may:
Rincrease the braking distance
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on ride comfort
Rbe more susceptible to damage
Maximum tire pressures
:Example: maximum permissible tire pres-
sure
Never exceed the maximum permissible tire
inflation pressure. Always observe the recom-
mended tire pressure for your vehicle when
adjusting the tire pressure (
Ypage 288).
iThe actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
290Tire pressure
Wheels and tires

Checking the tire pressures
Important safety notes
The tire pressure monitor does not warn you of:
Rincorrectly set tire pressure
Rsudden loss of tire pressure, e.g. from a for-
eign object that has penetrated the tire
Observe the notes on tire pressure
(
Ypage 288).
Information on air pressure for the tires on your
vehicle can be found:
Ron the vehicle's Tire and Loading Information placard on the B-pillar
Ron the tire pressure table in the fuel filler flap
Rin the "Tire pressure" section
Checking tire pressures manually
To determine and set the correct tire pressure,
proceed as follows:
XRemove the valve cap of the tire that is to be
checked.
XPress the tire pressure gauge securely onto
the valve.
XRead the tire pressure and compare it to the
recommended value on the Tire and Loading
Information placard or the tire pressure table(
Ypage 288).
XIf the tire pressure is too low, increase the tire
pressure to the recommended value.
XIf the tire pressure is too high, release air. To
do so, press down the metal pin in the valve,
using the tip of a pen for example. Then check
the tire pressure again using the tire pressure
checker.
XScrew the valve cap onto the valve.
XRepeat these steps for the other tires.
Tire pressure monitor
General notes
If a tire pressure monitor is installed, the vehi-
cle's wheels have sensors that monitor the tire
pressures in all four tires. The tire pressure mon-
itor warns you if the pressure drops in one or
more of the tires. The tire pressure monitor only
functions if the corresponding sensors are
installed in all wheels. Information on tire pressures is displayed in the
multifunction display. After a few minutes of
driving, the current tire pressure of each tire is
shown in the
Serv.
menu of the multifunction
display.
Example: current tire pressure display
For information on the message display, refer to
the "Checking the tire pressure electronically"
section (
Ypage 292).
Important safety notes
GWARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure rec-
ommended by the vehicle manufacturer on
the Tire and Loading Information placard on
the driver's door B-pillar or the tire pressure
label on the inside of the fuel filler flap. If your
vehicle has tires of a different size than the
size indicated on the Tire and Loading Infor-
mation placard or the tire pressure label, you
should determine the proper tire pressure for
those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale illuminates,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can lead to tire failure. Underinflation also
reduces fuel efficiency and tire tread life, and
may affect the vehicle's handling and stop-
ping ability.
Please note that the TPMS is not a substitute
for proper tire maintenance, and it is the driv-
Tire pressure291
Wheels and tires
Z

er's responsibility to maintain correct tire
pressure, even if underinflation has not
reached the level to trigger illumination of theTPMS low tire pressure telltale.
USA only:
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
detects a malfunction, the warning lamp will
flash for approximately a minute and then
remain continuously illuminated. This
sequence will be repeated every time the vehi-
cle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,
the system may not be able to detect or signal
low tire pressure as intended. TPMS malfunc-
tions may occur for a variety of reasons,
including the mounting of incompatible
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from func-
tioning properly. Always check the TPMS mal-
function telltale after replacing one or more
tires or wheels on your vehicle to ensure that
the replacement or alternate tires and wheels
allow the TPMS to continue to function prop-
erly.
It is the driver's responsibility to set the tire
pressure to that recommended for cold tires
which is suitable for the operating situation
(
Ypage 288). Note that the correct tire pressure
for the current operating situation must first be
taught-in to the tire pressure monitor. If a sub-
stantial loss of pressure occurs, the warning
threshold for the warning message is aligned to
the taught-in reference values. Restart the tire
pressure monitor after adjusting the pressure of
the cold tires (
Ypage 293). The current pres-
sures are saved as new reference values. As a
result, a warning message will appear if the tire
pressure drops significantly.
The tire pressure monitor does not warn you of
an incorrectly set tire pressure. Observe the
notes on the recommended tire pressure
(
Ypage 288).
The tire pressure monitor is not able to warn you
of a sudden loss of pressure, e.g. if the tire ispenetrat
ed by a foreign object. In the event of a
sudden loss of pressure, bring the vehicle to a
halt by braking carefully. Avoid abrupt steering
movements.
The tire pressure monitor has a yellow warning
lamp in the instrument cluster for indicating
pressure loss or a malfunction. Whether the
warning lamp flashes or lights up indicates
whether a tire pressure is too low or the tire
pressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, the tire
pressure on one or more tires is significantly
too low. The tire pressure monitor is not mal- functioning.
Rif the warning lamp flashes for approximately
a minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(
Ypage 221).
It may take up to ten minutes for a malfunction
of the tire pressure monitor to be indicated. A
malfunction will be indicated by the tire pres-
sure warning lamp flashing for approximately
one minute and then remaining lit. When the
malfunction has been rectified, the tire pressure
warning lamp goes out after a few minutes of
driving.
The tire pressure values indicated by the on-
board computer may differ from those meas-
ured at a gas station with a pressure gage. The
tire pressures shown by the on-board computer
refer to those measured at sea level. At high
altitudes, the tire pressure values indicated by a
pressure gage are higher than those shown by
the on-board computer. In this case, do not
reduce the tire pressures.
The operation of the tire pressure monitor can
be affected by interference from radio transmit-
ting equipment (e.g. radio headphones, two-way
radios) that may be being operated in or near the
vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in position 2
(Ypage 122) in the ignition lock.
XPress the =or; button on the steering
wheel to select the Serv.menu.
292Tire pressure
Wheels and tires

XPress the9or: button to select
Tire Pressure.
XPress a.
The current tire pressure of each tire is shown
in the multifunction display.
If the vehicle has been parked for over
20 minutes, the Tire pressure will be
displayed after driving a few minutesmessage appears.
After a teach-in process, the tire pressure mon-
itor automatically detects new wheels or new
sensors. As long as a clear allocation of the tire
pressure value to the individual wheels is not
possible, theTire
PressureMonitorActivedisplay message is shown instead of the tire
pressure display. The tire pressures are already
being monitored.
Tire pressure monitor warning mes-
sages
The tire pressure monitor detects a pressure
loss in one or more tires:
RIf the tire pressure monitor detects a pressure
loss in one or more tires, a warning message
is shown in the multifunction display. The yel-
low tire pressure warning lamp then lights up.
RIf thePlease Correct Tire Pressuremessage appears in the multifunction display,
the tire pressure in at least one tire is too low.
The tire pressure must be corrected when the
opportunity arises.
RIf theCheck Tiresmessage appears in the
multifunction display, the tire pressure in at
least one tire has dropped significantly. The
tires must be checked.
RIf the WarningTireMalfunctionmessage
appears in the multifunction display, the tire
pressure in at least one tire has dropped sud-
denly. The tires must be checked.
Observe the instructions and safety notes in the
display messages in the "Tires" section
(
Ypage 221).
If the wheel positions on the vehicle are rotated,
the tire pressures may be displayed for the
wrong positions for a short time. This is rectified after a few minutes of driving, and the tire pres-
sures are displayed for the correct positions.
Restarting the tire pressure monitor
When you restart the tire pressure monitor, all
existing warning messages are deleted and the
warning lamps go out. The monitor uses the cur-
rently set tire pressures as the reference valuesfor monitoring. In most cases, the tire pressure
monitor will automatically detect the new refer-
ence values after you have changed the tire
pressure. However, you can also set reference
values manually as described here. The tire
pressure monitor then monitors the new tire
pressure values.
XSet the tire pressure to the value recommen- ded for the corresponding driving situation on
the Tire and Loading Information placard on
the driver's side B-pillar (
Ypage 288).
Additional tire pressure values for different
loads can also be found on the tire pressure
table on the inside of the fuel filler flap
(
Ypage 288).
XMake sure that the tire pressure is correct on
all four wheels.
XEnsure that the SmartKey is in position 2in
the ignition lock.
XPress the =or; button on the steering
wheel to select the Serv.menu.
XPress the9or: button to select
Tire Pressure.
XPress a.
The multifunction display shows the current
tire pressure for the individual tires or the
Tire pressure will be displayed
after driving a few minutesmessage.
XPress the :button.
The UseCurrentPressuresasNewRef‐erenceValuesmessage appears in the mul-
tifunction display.
If you wish to confirm the restart:
XPress a.
The TirePress.MonitorRestartedmes-
sage appears in the multifunction display.
After driving for a few minutes, the system
checks whether the current tire pressures are
within the specified range. The new tire pres-
sures are then accepted as reference values
and monitored.
If you wish to cancel the restart:
XPress %.
The tire pressure values stored at the last
restart will continue to be monitored.
Tire pressure293
Wheels and tires
Z

Radio type approval for the tire pres-
sure monitor
CountryRadio type approval number
USAFCC ID: MRXMW2433A
FCCIC ID:MRXGG4 This device
complies with part 15 of the FCC
rules and with license exempt
RSS standards of Industry Can-
ada. Operation is subject to the
following conditions. (1) This
device may not cause harmful
interference, and (2) This device
must accept any interference
received, including interference
that may cause undesired oper-
ation. Le present appareil est
conforme d'industrie Canada
applicables aux appareils radio
exempts de licence. L'exploita-
tion est authorisee aux deux con-
ditions suivantes. (1) L'appareil
ne doit pas produire de brouil-
lage, et (2) L'autisatuer de l'ap-
pareil doit accepter tout brouil-
lage radioelectrique subi, meme
si le brouillage est susceptible
d'en compromettre le fonc-
tionnement. WARNING: Changes
or modifications not expressly
approved by the party responsi-
ble for compliance could void the
user's authority to operate the
equipment. The term "IC:" before the radio certification number
only signifies Canada technical
specifications were met.
FCC ID:MRXMC34MA4 This
device complies with part 15 of
the FCC rules and with license
exempt RSS standards of Indus-
try Canada. Operation is subject
to the following conditions. (1)
This device may not cause harm-
ful interference, and (2) This
device must accept any interfer-
ence rece ived
, including interfer-
ence that may cause undesired
operation. Le present appareil
est conforme d'industrie Canada
applicables aux appareils radio
exempts de licence. L'exploita-
tion est authorisee aux deux con- ditions suivantes. (1) L'appareil
CountryRadio type approval number
ne doit pas produire de brouil-
lage, et (2) L'autisatuer de l'ap-
pareil doit accepter tout brouil-
lage radioelectrique subi, meme
si le brouillage est susceptible
d'en compromettre le fonc-
tionnement. WARNING: Changes
or modifications not expressly
approved by the party responsi-
ble for compliance could void the
user's authority to operate the
equipment. The term "IC:" before the radio certification number
only signifies Canada technical
specifications were met.
CanadaIC: 2546A-MW2433A
IC:2546A-GG4 This device com-
plies with part 15 of the FCC
rules and with license exempt
RSS standards of Industry Can-
ada. Operation is subject to the
following conditions. (1) This
device may not cause harmful
interference, and (2) This device
must accept any interference
received, including interference
that may cause undesired oper-
ation. Le present appareil est
conforme d'industrie Canada
applicables aux appareils radio
exempts de licence. L'exploita-
tion est authorisee aux deux con-
ditions suivantes. (1) L'appareil
ne doit pas produire de brouil-
lage, et (2) L'autisatuer de l'ap-
pareil doit accepter tout brouil-
lage radioelectrique subi, meme
si le brouillage est susceptible
d'en compromettre le fonc-
tionnement. WARNING: Changes
or modifications not expressly
approved by the party responsi-
ble for compliance could void the
user's authority to operate the
equipment. The term "IC:" before
the radio certification number
only signifies Canada technical
specifications were met.
IC: 2546A-MC34MA4
294Tire pressure
Wheels and tires