MERCEDES-BENZ C-CLASS CABRIOLET 2018 Owner's Manual

Maximum tire load:is the maximum permis-
sible weight for which the tire is approved.
Do not overload the tires by exceeding the
specified load limit. The maximum permissible
load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side (
Ypage 322).
iThe actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
DOT, Tire Identification Number (TIN)
US tire regulations stipulate that every tire man-
ufacturer or retreader must imprint a TIN in or on
the sidewall of each tire produced.
The TIN is a unique identification number. The
TIN enables the tire manufacturers or retreaders
to inform purchasers of recalls and other safety-
relevant matters. It makes it possible for the
purchaser to easily identify the affected tires.
The TIN is made up of manufacturer identifica-
tion code ;, tire size =, tire type code ?and
manufacturing date A.
DOT (Department of Transportation): tire
symbol :marks that the tire complies with the
requirements of the U.S. Department of Trans-
portation.
Manufacturer identification code: manufac-
turer identification code ;provides details on
the tire manufacturer. New tires have a code
with two symbols. Retreaded tires have a code
with four symbols.
For further information about retreaded tires,
see (
Ypage 336).
Tire size: identifier=describes the tire size.
Tire type code: tire type code?can be used by
the manufacturer as a code to describe specific
characteristics of the tire. Date of manufacture:
date of manufactureA
provides information about the age of a tire. The
first and second positions represent the week of
manufacture, starting with "01" for the first cal-
endar week. Positions three and four represent
the year of manufacture. For example, a tire that
is marked "3214" was manufactured in week 32
in 2014.
iTire data is vehicle-specific and may deviate
from the data in the example.
Tire characteristics
This information describes the type of tire cord
and the number of layers in sidewall :and
under tire tread ;.
iTire data is vehicle-specific and may deviate
from the data in the example.
Definition of terms for tires and loading
Tire ply composition and material used
Describes the number of plies or the number of
layers of rubber-coated fabric in the tire tread
and sidewall. These are made of steel, nylon,
polyester and other materials.
Bar
Metric unit for tire pressure. 14.5038 pounds
per square inch (psi) and 100 kilopascals (kPa)
are the equivalent of 1 bar.
DOT (Department of Transportation)
DOT-marked tires fulfill the requirements of the
U S Department of Transportation.
Normal occupant weight
The number of occupants for which the vehicle
is designed multiplied by 68 kilograms (150 lbs).
All about wheels and tires329
Wheels and tires
Z

Uniform Tire Quality Grading Standards
A uniform standard to grade the quality of tires
with regards to tread quality, tire traction and
temperature characteristics. The quality grad-
ing assessment is made by the manufacturer
following specifications from the U.S. govern-
ment. The ratings are molded into the sidewall ofthe tire.
Recommended tire pressures
The recommended tire pressure applies to the
tires mounted at the factory.
The Tire and Loading Information placard con-
tains the recommended tire pressures for cold
tires on a fully loaded vehicle and for the maxi-
mum permissible vehicle speed.
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.
Increased vehicle weight due to optional
equipment
The combined weight of all standard and
optional equipment available for the vehicle,
regardless of whether it is actually installed on
the vehicle or not.
Rim
This is the part of the wheel on which the tire is
mounted.
GAWR (Gross Axle Weight Rating)
The GAWR is the maximum gross axle weight
rating. The actual load on an axle must never
exceed the gross axle weight rating. The gross
axle weight rating can be found on the vehicle
identification plate on the B-pillar on the driver's
side.
Speed rating
The speed rating is part of the tire identification.
It specifies the speed range for which the tire is
approved.
GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight of
the vehicle including fuel, tools, the spare wheel,
accessories installed, occupants, luggage and
the drawbar noseweight, if applicable. The gross
vehicle weight must not exceed the gross vehi-
cle weight rating GVWR as specified on the vehi-
cle identification plate on the B-pillar on the
driver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible gross
weight of a fully loaded vehicle (the weight of the
vehicle including all accessories, occupants,
fuel, luggage and the drawbar n
oseweight, if
applicable). The gross vehicle weight rating is
specified on the vehicle identification plate on
the B-pillar on the driver's side.
Maximum loaded vehicle weight
The maximum weight is the sum of:
Rthe curb weight of the vehicle
Rthe weight of the accessories
Rthe load limit
Rthe weight of the factory installed optional
equipment
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure is
bar. 100 kilopascals (kPa) are the equivalent of
1 bar.
Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall of
the tire. This specifies the load-bearing capacity
more precisely.
Curb weight
The weight of a vehicle with standard equipment
including the maximum capacity of fuel, oil and
coolant. It also includes the air-conditioning sys-
tem and optional equipment if these are instal-
led in the vehicle, but does not include passen-
gers or luggage.
Maximum load rating
The maximum tire load is the maximum permis-
sible weight in kilograms or lbs for which a tire is
approved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one tire.
Maximum load on one tire
Maximum load on one tire. This is calculated by dividing the maximum axle load of one axle by
two.
330All about wheels and tires
Wheels and tires

PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire width
in percent.
Tire pressure
This is pressure inside the tire applying an out-
ward force to each square inch of the tire's sur-
face. The tire pressure is specified in pounds per
square inch (psi), in kilopascal (kPa) or in bar.
The tire pressure should only be corrected when
the tires are cold.
Cold tire pressure
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)
Tread
The part of the tire that comes into contact with
the road.
Bead
The tire bead ensures that the tire sits securely
on the wheel. There are several steel wires in the
bead to prevent the tire from coming loose fromthe wheel rim.
Sidewall
The part of the tire between the tread and the
bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
parts and more than 5 lbs (2.3 kg). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-per-
formance battery, are not included in the curb
weight and the weight of the accessories.
TIN (Tire Identification Number)
This is a unique identifier which can be used by
a tire manufacturer to identify tires, for example
for a product recall, and thus identify the pur-
chasers. The TIN is made up of the manufactur-
er's identity code, tire size, tire type code and
the manufacturing date.
Load bearing index
The load bearing index (also load index) is a code
that contains the maximum load bearing capa-
city of a tire.
Traction
Traction is the result of friction between the tires
and the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are distrib-
uted over the tire tread. If the tire tread is level
with the bars, the wear limit of áin (1.6 mm)
has been reached.
Occupant distribution
The distribution of occupants in a vehicle at their
designated seating positions.
Total load limit
Nominal load and luggage load plus 68 kg
(150 lbs) multiplied by the number of seats in
the vehicle.
Changing a wheel
Flat tire
The "Breakdown assistance" section
(Ypage 296) contains information and notes on
how to deal with a flat tire. Information on driv-
ing with MOExtended tires in the event of a flat
tire can be found under "MOExtended tires (tires
with run-flat characteristics" (
Ypage 297).
Rotating the wheels
GWARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or tires have different dimensions. The wheel brakes or suspension components
may also be damaged. There is a risk of acci-
dent.
Rotate front and rear wheels only if the wheels and tires are of the same dimensions.
!On vehicles equipped with a tire pressure
monitor, electronic components are located
in the wheel.
Changing a wheel331
Wheels and tires
Z

Tire-mounting tools should not be used near
the valve. This could damage the electronic
components.
Only have tires changed at a qualified spe-
cialist workshop.
Always observe the instructions and safety
notes in the "Mounting a wheel" section
(
Ypage 332).
The wear patterns on the front and rear tires
differ, depending on the operating conditions.
Rotate the wheels before a clear wear pattern
has formed on the tires. Front tires typically
wear more on the shoulders and the rear tires in the center.
On vehicles that have the same size front and
rear wheels, you can rotate the wheels accord-
ing to the intervals in the tire manufacturer's
warranty book in your vehicle documents. If no
warranty book is available, the tires should be
rotated every 3,000 to 6,000 miles (5,000 to
10,000 km). Depending on tire wear, this may
be required earlier. Do not change the direction
of wheel rotation.
Clean the contact surfaces of the wheel and the
brake disc thoroughly every time a wheel is rota-
ted. Check the tire pressure and, if necessary,
restart the tire pressure loss warning system
(
Ypage 319) or the tire pressure monitor
(Ypage 321).
Direction of rotation
Tires with a specified direction of rotation have
additional benefits, e.g. if there is a risk of hydro- planing. These advantages can only be gained if
the tires are installed corresponding to the
direction of rotation.
An arrow on the sidewall of the tire indicates its
correct direction of rotation.
Storing wheels
Store wheels that are not being used in a cool,
dry and preferably dark place. Protect the tires
from oil, grease, gasoline and diesel.
Mounting a wheel
Preparing the vehicle
XStop the vehicle on solid, non-slippery and
level ground.
XApply the electric parking brake manually.
XBring the front wheels into the straight-ahead position.
XShift the transmission to position j.
XMake sure that the vehicle level is set to "Nor-
mal" on vehicles with AIRMATIC (Ypage 164).
XSwitch off the engine.
XVehicles without KEYLESS-GO:remove the
SmartKey from the ignition lock.
XVehicles with KEYLESS-GO start-function
or KEYLESS-GO: open the driver's door.
The vehicle electronics are now in key posi-
tion u. This is the same as the key having
been removed.
XVehicles with KEYLESS-GO start-function
or KEYLESS-GO: remove the Start/Stop but-
ton from the ignition lock (
Ypage 124).
XMake sure that the engine cannot be started
via your smartphone (Ypage 126).
XIf included in the vehicle equipment, remove
the tire-change tool kit from the vehicle.
XSafeguard the vehicle against rolling away.
Securing the vehicle to prevent it from
rolling away
If your vehicle is equipped with a wheel chock, it
can be found in the tire-change tool kit
(
Ypage 296).
The folding wheel chock is an additional safety
measure to prevent the vehicle from rolling
away, for example when changing a wheel.
332Changing a wheel
Wheels and tires

XFold both plates upwards:.
XFold out lower plate;.
XGuide the lugs on the lower plate fully into the
openings in base plate =.
XPlace chocks or other suitable items under
the front and rear of the wheel that is diago-
nally opposite the wheel you wish to change.
Raising the vehicle
GWARNING
If you do not position the jack correctly at the
appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
!Only position the jack at the appropriate
jacking point of the vehicle. Otherwise, you
could damage the vehicle.
Observe the following when raising the vehi-
cle:
RTo raise the vehicle, only use the vehicle-spe-
cific jack that has been tested and approved
by Mercedes-Benz. If used incorrectly, the
jack could tip over with the vehicle raised.
RThe jack is designed only to raise and hold the
vehicle for a short time while a wheel is being
changed. It must not be used for performing
maintenance work under the vehicle.
RAvoid changing the wheel on uphill and down- hill slopes.
RBefore raising the vehicle, secure it from roll-
ing away by applying the parking brake and inserting wheel chocks. Do not disengage the
parking brake while the vehicle is raised.
RThe jack must be placed on a firm, flat and
non-slip surface. On a loose surface, a large,
flat, load-bearing underlay must be used. On a
slippery surface, a non-slip underlay must be
used, e.g. rubber mats.
RDo not use wooden blocks or similar objects
as a
jack underlay. Otherwise, the jack will not
be able to achieve its load-bearing capacity
due to the restricted height.
RMake sure that the distance between the
underside of the tires and the ground does not
exceed 1.2 in (3 cm).
RDo not place your hands or feet under the
raised vehicle.
RDo not lie under the vehicle.
RDo not start the engine when the vehicle is
raised.
RDo not open or close a door or the trunk lid
when the vehicle is raised.
RMake sure that no persons are present in the
vehicle when the vehicle is raised.
Vehicles with alloy wheels and hub caps: the
wheel bolts are covered by a hub cap. Before you
can unscrew the wheel bolts, you must remove
the hub cap. Two different variants can be instal- led.
Vehicles with plastic hub cap:
XTo remove: turn the center cover of hub
cap :counter-clockwise and remove.
XTo install: before installing, ensure that hub
cap :is in the open position. To do this, turn
the center cover counter-clockwise.
XPosition hub cap :and turn the center cover
clockwise until hub cap :engages physically
and audibly.
XMake sure that hub cap :is installed
securely.
Changing a wheel333
Wheels and tires
Z

Vehicles with aluminum hub cap:
XTo remove:take socket;and wheel wrench
= from the vehicle tool kit (Ypage 296).
XPosition socket ;on hub cap :.
XPosition lug wrench =on socket ;.
XUsing lug wrench =, turn hub cap:coun-
ter-clockwise and remove it.
XTo install: before installing, check hub cap :
and the wheel area for soiling and clean if
necessary.
XPut hub cap :in position and turn until it is in
the right position.
XPosition socket ;on hub cap :.
XAttach lug wrench =to socket ;and
tighten hub cap :.
The tightening torque must be
18 lb-ft (25 Nm) .
iNotethat the hub cap should be tightened
to the specified torque of 18 lb-ft (25 Nm).
Mercedes-Benz recommends that you have
the hub cap installed at a qualified specialist
workshop.
XUsing lug wrench =, loosen the bolts on the
wheel you wish to change by about one full
turn. Do not unscrew the bolts completely.
The jacking points are located just behind the
front wheel housings and just in front of the rear
wheel housings (arrows).
Mercedes-AMG vehicles and vehicles with
AMG equipment: to protect the vehicle body,
the vehicle has covers installed next to the jack-
ing points on the outer sills.
XPosition jack Bat jacking point A.
XMake sure the foot of the jack is directly
beneath the jacking point.
XTurn crankCclockwise until jack Bsits
completely on jacking point A. The base of
the jack must lie evenly on the ground.
XTurn crank Cuntil the tire is raised a maxi-
mum of 1.2 in (3 cm) from the ground.
334Changing a wheel
Wheels and tires

Removing a wheel
!Mercedes-AMG vehicles with ceramic-
brake disc: during removal and repositioning
of the wheel, the wheel rim can strike the
ceramic-brake disc and damage it. Therefore,
you should proceed carefully and get a sec-
ond person assist to you. Alternatively, you
can use a second alignment bolt.
!Do not place wheel bolts in sand or on a dirty
surface. The bolt and wheel hub threads could
otherwise be damaged when you screw them
in.
When mounting/removing wheels, and for as
long as the wheels are removed, avoid applying
any external force on the brake disks. This could
impair the level of comfort when braking.
XUnscrew the uppermost wheel bolt com-
pletely.
XScrew alignment bolt :into the thread
instead of the wheel bolt.
XUnscrew the remaining wheel bolts fully.
XRemove the wheel.
Mounting a new wheel
GWARNING
Oiled or greased wheel bolts or damaged
wheel bolts/hub threads can cause the wheel bolts to come loose. As a result, you could
lose a wheel while driving. There is a risk of
accident.
Never oil or grease wheel bolts. In the event of
damage to the threads, contact a qualified
specialist workshop immediately. Have the
damaged wheel bolts or hub threads
replaced/renewed. Do not continue driving.
GWARNING
If you tighten the wheel bolts or wheel nuts
when the vehicle is raised, the jack could tip
over. There is a risk of injury.
Only tighten the wheel bolts or wheel nuts
when the vehicle is on the ground.
Always pay attention to the instructions and
safety notes in the "Changing a wheel" section
(
Ypage 331).
Only use wheel bolts that have been designed
for the wheel and the vehicle. For safety rea-
sons, Mercedes-Benz recommends that you
only use wheel bolts which have been approved for Mercedes-Benz vehicles and the respective
wheel.
!Mercedes-AMG vehicles with ceramic-
brake disc: during removal and repositioning
of the wheel, the wheel rim can strike the
ceramic-brake disc and damage it. Therefore,
you should proceed carefully and get a sec-
ond person assist to you. Alternatively, you
can use a second alignment bolt.
!To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt.
XClean the wheel and wheel hub contact sur-
faces.
XSlide the wheel to be mounted onto the align-
ment bolt and push it on.
XTighten the wheel bolts until they are finger-
tight.
XUnscrew the alignment bolt.
XTighten the last wheel bolt until it is finger-
tight.
Changing a wheel335
Wheels and tires
Z

Lowering the vehicle
GWARNING
The wheels could work loose if the wheel nuts and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed.
XTurn the crank of the jack counter-clockwise
until the vehicle is once again standing firmly
on the ground.
XPlace the jack to one side.
XTighten the wheel bolts evenly in a crosswisepattern in the sequence indicated (: toA).
The tightening torque must be 111 lb-ft
(150 Nm) .
XTurn the jack back to its initial position.
XStow the jack and the rest of the vehicle tools
in the trunk again.
XMercedes-AMG vehicles and vehicles
with AMG equipment: insert the cover into
the outer sill.
XCheck the tire pressure of the newly mounted
wheel and adjust it if necessary.
Observe the recommended tire pressure
(
Ypage 315).
When you are driving with the collapsible spare
wheel mounted, the tire pressure loss warning
system or the tire pressure monitor cannot func-
tion reliably. Only restart the tire pressure loss
warning system or tire pressure monitor when
the defective wheel has been replaced with a
new wheel.
Vehicles with a tire pressure control sys-
tem: all installed wheels must be equipped with
functioning sensors.
Wheel/tire combination
You can ask for information regarding permitted wheel/tire combinations at an authorized
Mercedes-Benz Center.
!For safety reasons, Mercedes-Benz recom-
mends that you only use tires and wheels
which have been approved by Mercedes-Benz
specifically for your vehicle.
These tires have been specially adapted for
use with the control systems, such as ABS or
ESP
®, and are marked as follows:
RMO = Mercedes-Benz Original
RMOE = Mercedes-Benz Original Extended
(tires featuring run-flat characteristics)
RMO1 = Mercedes-Benz Original (only cer-
tain AMG tires)
Mercedes-Benz Original Extended tires may
only be used on wheels that have been spe-
cifically approved by Mercedes-Benz.
Only use tires, wheels or accessories tested
and approved by Mercedes-Benz. Certain
characteristics, e.g. handling, vehicle noise
emissions or fuel consumption, may other-
wise be adversely affected. In addition, when
driving with a load, tire dimension variations
could cause the tires to come into contact
with the bodywork and axle components. This
could result in damage to the tires or the vehi- cle.
Mercedes-Benz accepts no liability for dam-
age resulting from the use of tires, wheels or
accessories other than those tested and
approved.
Information on tires, wheels and approved
combinations can be obtained from any quali-
fied specialist workshop.
!Retreaded tires are neither tested nor rec-
ommended by Mercedes-Benz, since previ-
ous damage cannot always be detected on
retreaded tires. As a result, Mercedes-Benz
cannot guarantee vehicle safety if retreaded
tires are mounted. Do not mount used tires if
you have no information about their previous
usage.
The recommended pressures for various oper-
ating conditions can be found:
Ron the Tire and Loading Information placard
on the B-pillar on the driver's side
Rin the tire pressure table in the fuel filler flap
336Wheel/tire combination
Wheels and tires

Observe the notes on recommended tire pres-
sures under various operating conditions
(
Ypage 315).
Check tire pressures regularly, and only when
the tires are cold. Comply with the maintenance
recommendations of the tire manufacturer in
the vehicle document wallet.
Notes on the vehicle equipment – always equip
the vehicle:
Rwith tires of the same size on a given axle (left
and right)
Rwith the same type of tires at a given time
(summer tires, winter tires, MOExtended
tires)
Exception: it is permissible to install a differ-
ent type or make in the event of a flat tire.
Observe the "MOExtended tires (tires with
run-flat characteristics" section (
Ypage 297).
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 properties, e.g.
winter tires. A TIREFIT kit may be obtained from
a qualified specialist workshop.
Wheel/tire combination337
Wheels and tires
Z

Information regarding technical data
i
The dat astate dher especifically refers to a
vehicl ewit hstandard equipment. Consult an
authorize dMercedes-Ben zCente rfor th e
dat afor all vehicl evariants and trim levels.
Vehicle electronics
Installing two-way radios and mobile
phones
GWARNIN G
The electromagneti cradiation from two-way
radios can interfere wit hth evehicl eelectron -
ics if two-way radios are manipulated or ret -
rofitte dincorrectly. This could jeopardiz eth e
operating safet yof th evehicle. Ther eis aris k
of an accident.
You should hav eall wor kon electrical and
electronic component scarried out at aquali-
fie dspecialist workshop.
GWARNIN G
If you incorrectl yoperate two-way radios in
th evehicle, th eelectromagneti cradiation
may interfere wit hth evehicl eelectronics ,for
exampl eif:
Rth etwo-way radi ois no tconnecte dto an
exterio rantenna
Rth eexterio rantenna is no tcorrectl ymoun -
te dor is no tlow-reflection
This could jeopardiz eth eoperating safet yof
th evehicle. Ther eis aris kof an accident.
Hav eth elow-reflection exterio rantenna
installed at aqualified specialist workshop.
Always connec ttwo-way radios to th elow-
reflection exterio rantenna when operating in
th evehicle.
!The operating permit may be invalidated if
th einstruction sfor installation and use of
two-way radios are no tobserved. In particular, th
efollowin gcondition smust be
complied with:
Ronly approve dwavebands may be used.
Robserv eth emaximum permissible output
in these wavebands.
Ronly approve dantenna position smay be
used.
Excessiv elevels of electromagneti cradiation
may caus edamag eto your healt hand th ehealt h
of others. Using an exterio rantenna takes int o
accoun tcurren tscientific discussion srelating
to th epossible healt hhazards that may result
from electromagneti cfields.
Approved antenna position s
:Rear fender
On th erear fenders, it is recommended to posi-
tion th eantenna on th eside of th evehicl eclos-
est to th ecenter of th eroad .
Use Technical Specification ISO/TS 2160 9
(Road Vehicles –"EM Cguidelines for installa-
tion of aftermarket radi ofrequency transmitting
equipment") when retrofitting two-way radios.
Observ eth elegal requirements for accessory
parts.
If your vehicl ehas installation sfor two-way radi o
equipment, use th epower suppl yor antenna
connection sintended for use wit hth ebasic wir-
ing .Be sur eto observ eth emanufacturer' sSup -
plemen twhen installing.
Deviation swit hrespec tto frequency bands,
maximum transmission output sor antenna
position smust be approve dby Mercedes-Benz.
338Vehicle electronics
Technical data