2018 MERCEDES-BENZ SLC ROADSTER wheel size

Tire and LoadingInfor matio nplacard
:Recommended tire pressures
The Tire and Loading Informatio nplacard is on
the B-pillar on the driver's side (
Ypage 271).
The Tire and Loading Informatio nplacard con-
tains the recommende dtire pressures for cold
tires. The recommende dtire pressures ar evalid
for the maximum permissibl eloa da nd up to the
maximum permissibl evehicl espeed.
Tire pressure table
The tire pressure table is on the insid eofthe fuel
fille rflap. It shows the tire pressure for al ltires
permitted at the factory for thisv ehicle; see
illustratio n(example).
The tire pressure table contains the recommen-
de dp ressures for col dtiresfor various operat-
ing conditions, i.e .differin gloa da nd spee dcon-
ditions.
If at ire size precedes atire pressure, the fol-
lowing tire pressure informatio niso nlyv alid for
thatt ire size; see illustratio n(example).
The load conditions "partiall yladen "and "fully
laden" ar edefine dint he table for different num-
bers of occupants and amounts of luggage.T he
actual numbe rofseats mayd iffer.
Some tire pressure table sshowo nlyt he rim
diameters instea dofthe full tire size, e.g. R18.
Ri md iame terisp artoft he tire size and can be
found on the tire sidewall (
Ypage 275).
If the tire pressures have been set to the lower
values for lighte rloads and/or lowe rroad
speeds ,the pressures shoul dbereset to the
highe rvalues :
Rif youwanttod rive with an increased load
and/or
Rif yo uwanttod rive at highe rroa ds peeds
The tire pressures for increased load sand/or
highe rroa ds peeds, shown in the tire pressure
table ,mayhave anegative effect on driving
comfort.
If the tire pressure is not set correctly, thisc an
lead to an excessive build-u pofheata nd asud-
de nlossofp ressure.
For mor einformation, contact aquali fied spe-
cialist workshop.
264Tire pressure
Wheel sand tires

Example: current tire pressure display
For informationonthe message display, refer to
the "Checking the tire pressure electronically"
sectio n(
Ypage 269).
Important safety notes
GWARNING
Each tire ,including the spar e(ifprovided),
shoul dbec hecked at leas tonce amonth
when col dand inflate dtothe pressure rec-
ommended by the vehicl emanufacturer on
the Tire and Loading Informatio nplacard on
the driver's door B-pillar or the tire pressure
labe lont he insid eofthe fuel fille rflap. If your
vehicl ehastire sofad ifferent size thant he
size indicated on the Tire and Loading Infor-
matio nplacard or the tire pressure label, you
shoul ddetermine the prope rtire pressure for
thos etires.
As an adde dsafety feature, your vehicl ehas
been equipped with atire pressure monitoring
system (TPMS )thati llum inate salowtire pres-
sure telltale when one or mor eofyourtires
ar es ignificantl yunderinflated .Accordingly,
when the lo wtire pressure telltale illuminates,
yo us houl dstop and check your tire sassoon
as possible, and inflate themtot he proper
pressure. Driving on asignificantl yunderin-
flated tire causes the tire to overheat and can lead to tire failure. Underinflatio nalso
reduce sfue lefficiency and tire trea dlife, and
maya ffect the vehicle's handling and stop-
ping ability.
Please note thatt he TPMS is notasubst itute
for prope rt
ire ma
intenance ,and it is the driv-
er' sresponsibility to maintain correct tire
pressure, eve nifunderinflatio nhasnot
reachedt he level to triggeri llumination of the
TPMS lo wtire pressure telltale.
Your vehicl ehasalso been equipped with a
TPMS malfunctio nindicator to indicate if the
system is not operating properly .The TPMS
malfunctio nindicator is combine dwitht he
lo wt ire pressure telltale .Whent he system
detects amalfunction, the warning lamp will
flash for approximately aminute and then
remai ncontinuously illuminated. This
sequence will be repeated every time the vehi-
cle is started as long as the malfunction
exists.
When the malfunctio nindicator is illuminated,
the system mayn ot be able to detect or signal
lo wt ire pressure as intended. TPMS malfunc-
tions mayo ccurfor av ariety of reasons,
including the installatio nofincompatible
replacement or alternate tire sorwheelson
the vehicl ethatp revent the TPMS fromf unc-
tioning properly .Alway scheck the TPMS mal-
functio ntelltale after replacing one or more
tire sorw heelsony ourvehicl etoe nsurethat
the replacement or alternate tire sand wheels
allo wthe TPMS to continue to functio nprop-
erly.
It is the driver's responsibility to set the tire
pressure to thatr ecommendedfor col dtires
which is suitabl efor the operating situation
(
Ypage 263).N ote thatthe correct tire pressure
for the current operating situatio nmustfirst be
taught-i ntothe tire pressure monitor. If asub-
stantia llos sofp ressure occurs, the warning
threshold for the warning message is aligned to
the taught-i nreference values. Restart the tire
pressure monitor after adjusting the pressure of
the col dtires(
Ypage 270). The current pres-
sures ar esaved as new reference values. As a
result, awarning message will appear if the tire
pressure drops significantly.
The tire pressure monitor does not warn yo uof
an incorrectly set tire pressure. Observe the
note sont he recommende dtire pressure
(
Ypage 263).
The tire pressure monitor is not able to warn you
of as udde nlossofp ressure, e.g .ifthe tire is
penetrated by aforeign object. In the event of a
sudden loss of pressure, bring the vehicl etoa
halt by braking carefully. Avoi dabrup tsteering
movements.
268Tire pressure
Wheel sand tires

Maximum permissible gross vehicle
weight rating
XSpecification for maximumgross vehicle
weight :is listed in the Tire and Loading
Informatio nplacard: "The combined weight of
occupants and cargo should never exceed
XXX kilograms or XXX lbs."
The gross weight of all vehicleo ccupants, load
and luggage must not exceed the specified
value.
iThe specifications shownont he Tire and
Loading Informatio nplacard in the illustration
are examples. The maximu mpermissible
gross vehiclew eight rating is vehicle-specific
and may differf rom that in the illustration.
You can find the vali dmaximu mpermissible
gross vehiclew eight rating for you rvehicleo n
the Tire and Loading Informatio nplacard.
Number of seats
Maximu mnumber of seats :indicates the
maximu mnumber of occupants allowedt o
travel in the vehicle. This information can be
found on the Tire and Loading Informatio nplac-
ard.
iThe specifications shownont he Tire and
Loading Informatio nplacard in the illustration
are examples. The number of seats is vehicle-
specific and can differf rom the details shown.
The number of seats in you rvehiclec an be
found on the Tire and Loading Information
placard.
Determiningt he correct load limit
Step-by-ste pinstructions
The following steps have been developed as
required of all manufacturers under Title 49,
Cod eofU .S. FederalR egulations, Part 575 pur-
suant to the "National Traffi cand Motor Vehicle
Safety Act of 1966".
XStep 1: Locate the statement "The combined
weight of occupants and cargo should never
exceed XXX kg or XXX lbs." on you rvehicle’s
Tire and Loading Informatio nplacard.
XStep 2: Determine the combined weight of
the drivera nd passengers that wil lberiding in
you rvehicle.
XStep 3: Subtract the combined weight of the
drivera nd passengers from XXX kilograms or
XXX lbs.
XStep 4: The resulting figure equals the avail-
abl eamount of cargo and luggage loadc apa-
city. For example, if the "XXX "amount equals
1400 lbs and there wil lbefive 150-lb pas-
sengers in you rvehicle, the amount of avail-
abl ecargo and luggage loadc apacity is
650 lbs (1400 -750 (5 x150) = 650 lbs).
XStep 5: Determine the combined weight of
luggage and cargo being loaded on the vehi-
cle. That weight may not safel yexceed the
available cargo and luggage loadc apacity cal-
culated in step 4.
Example:s teps1to3
The following table showse xamples on how to
calculate total and cargo loadc apacities with
varying seating configurations and number and
size of occupants. The following examples use a
loadl imitof1 500 lbs (680 kg). This is for illus-
tration purposes only. Make sure you are
using the actua lloadl imitf or you rvehicles tated
on you rvehicle's Tire and Loading Information
placard (
Ypage2 71).
272Loading the vehicle
Wheels and tires

Tire labeling
Overview
:Unifor mTireQ ualit yGradin gStandard
(Ypage 278)
;DOT, Tire Identification Number
(Ypage 277)
=Maximum tire load (Ypage 277)
?Maximum tire pressure (Ypage 266)
AManufacturer
BTire material (Ypage 278)
CTire size designation, load-bearing capacity
and spee drating (Ypage 275)
DLoadi ndex (Ypage 277)
ETire name
The markings describe dabove ar eont he tire in
additio ntothe tire nam e(sales designation) and
the manufacturer's name.
iTire data is vehicle-specific and mayd eviate
fromt he data in the example.
Tire size designation ,loa d-bearing
capacity and speed rating
GWARNING
Exceeding the stated tire load-bearing capa-
city and the approved maximum spee dcould
lead to tire damage or the tire bursting. There is ar iskofa ccident.
Therefore ,onlyu setire types and sizes
approved for your vehicl emodel .Observe the
tire load rating and spee drating required for
your vehicle.
:Tire width
;Nomina laspec tratio in %
=Tire code
?Rimd iame ter
ALoadb earing index
BSpeed rating
General: depending on the manufacturer's
standards ,the size imprinted in the tire wall may
not contain any letters or mayc ontain one letter
thatp recedes the size description.
If there is no letter preceding the size descrip-
tio n(as shown above): these ar epassenger
vehicl etiresa ccording to Europea nmanufac-
turing standards.
If "P "precedes the size description: these are
passenge rvehicl etiresa ccording to U.S. man-
ufacturin gstandards.
If "LT" precedes the size description: these are
light truck tire saccording to U.S. manufacturing
standards.
If "T "precedes the size description: compact
emergency wheels with high tire pressure that
ar eo nlyd esig nedf or temporary us einanemer-
gency.
Tire width: tire width:shows the nominal tire
width in millimeters.
Height-width ratio: aspect ratio;is the size
ratio between the tire height and tire width and
is shown in percent. The aspect ratio is calcula-
ted by dividing the tire width by the tire height.
Tire code: tire code=specifie sthe tire type.
"R "r epresents radial tires; "D" represents diag-
ona ltire s; "
B" represents diagona
lradial tires.
Optionally ,tire sw itham aximum spee dofover
149 mph (24 0km/h )mayhave "ZR" in the size
Alla bout wheels an dtires275
Wheel sand tires
Z

description, dependingonthe manufacturer
(e.g. 245/40 ZR 18).
Rim diameter: rim diameter?is the diameter
of the bead seat, not the diameter of the rim
flange. The rim diameter is specified in
inches (in).
Load-bearing index: load-bearing indexAis a
numerical code that specifies the maximum
load-bearing capacityofat ire.
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'ss ide (
Ypage 271).
Example:
Load-bearin gindex 91 indicates amaximum
load of 1,356lb( 615 kg) that the tires can bear.
For further information on the maximum tire
load in kilograms and lbs, see (
Ypage 277).
For further information on the load bearing
index ,see "Load index "(
Ypage 277).
Speed rating: speed ratingBspecifies the
approved maximum speed of the tire.
iTire data is vehicle-specific and may deviate
from the data in the example.
Regardless of the speed rating, always observe
the speed limits. Driv ecarefully and adapt your
driving style to the traffic conditions.
Summer
tires
IndexSpeed rating
Qup to 100 mph (160 km/h)
Rup to 106 mph (170 km/h)
Sup to 112 mph (180 km/h)
Tup to 118 mph (190 km/h)
Hup to 130 mph (210 km/h)
Vup to 149 mph (240 km/h)
Wup to 168 mph (270 km/h)
Yup to 186 mph (300 km/h)
ZR...Yup to 186 mph (300 km/h)
ZR...(..Y)over 186 mph (300 km/ h)
ZRover 149 mph (240 km/h)
ROptionally, tires withamaximum speed of
over 149 mph (240k m/h) may have "ZR" in
the sized escription, depending on the man-
ufacturer (e.g .245/4 0ZR18).
The service specification is made up of load-
bearingi ndexAand speed rating B.
RIf the sizedescription of your tir eincludes
"ZR" and there are no service specifications,
ask the tir emanufacturer in order to findo ut
the maximum speed.
If as ervice specification is available, the max-
imum speed is limited accordingtot he speed
rating in the service specification .Example:
245/4 0ZR18 97 Y. In this example, "97 Y" is
the service specification .The letter "Y" rep-
resent sthe speed rating. The maximum
speed of the tir eislimited to 186 mph
(300k m/h).
RThe sized escription for all tires with maxi-
mum speeds of over 186 mph (300k m/h)
must include "ZR", andthe service specifica-
tion must be given in parentheses. Example:
275/4 0ZR18( 99 Y). Spee drating "(Y)" indi-
cates that the maximum speed of the tir eis
over 186 mph (300k m/h).A sk the tir eman-
ufacturer about the maximum speed.
All-
weather
tires and
winter
tires
IndexSpeed rating
QM +S1up to 100 mph (160k m/h)
TM +S1up to 118 mph (190k m/h)
HM +S1up to 130 mph (210k m/h)
VM +S1up to 149 mph (240k m/h)
iNot all tires with the M+S marking provide
the driving characteristics of winter tires. In
additio ntothe M+S marking, winter tires also
have the isnowflakes ymbol on the tire
wall. Tires with this marking fulfill the require-
ments of the Rubber Manufacturers Associa-
tion (RMA) and the Rubber Association of
Canada (RAC) regarding the tir etraction on
snow. They have been especially developed
for driving on snow.
1Or M+S ifor winter tires.
276All about wheels and tires
Wheels and tires

An electronic speed limiterprevents your vehi-
cle from exceeding aspeed of 130 mph
(21 0km/h).
The speed rating of tire smounted at the factory
maybeh ighe rthant he maximu mspeed thatt he
electronic speed limite rpermits.
Make sure thaty ourtire sh avet he required
speed rating ,e.g.w henb uyin gnew tires. The
required speed rating for your vehicl ecan be
found in the "tires "sectio n(
Ypage 284).
Further informatio nabout reading tire data can
be obtained from any qualified specialist work-
shop.
Load index
In additio ntothe load-bearing index, load
index :maya lsobei mprinte donthe sidewall
of the tire .You will find thisa fterthe letter that
identifie sthe speed rating (
Ypage 275).
RIf no specification is given: no text (a sinthe
exampl eabove), represents astandard load
(SL) tire
RXL or Extra Load: represents areinforced tire
RLight Load: represents alight load tire
RC, D, E: represents aloa dr ange thatd epends
on the maximu mloadt hatt he tire can carry at
ac ertain pressure
iTire data is vehicle-specific and mayd eviate
from the data in the example.
Maximum load rating
Maximu mtire load :is the maximu mpermis-
sibl ew eigh tfor which the tire is approved.
Do not overload the tire sbyexceeding the
specified load limit. The maximu mpermissible
load can be found on the vehicle's Tire and
Loading Informatio nplacard on the B-pillar on
the driver's side (
Ypage 271).
iThe actual values for tire sarevehicle-spe-
cifi cand mayd eviate from the values in the
illustration.
DOT, Tire Identificatio nNumbe r(TIN)
US tire regulations stipulate thate very tire man-
ufacturer or retreader must imprint aTIN in or on
the sidewall of each tire produced.
The TIN is auniqu eide ntificatio nnumber. The
TIN enables the tire manufacturer sorretreaders
to inform purchaser sofrecallsand othe rsafety-
relevant matters .Itmakes it possibl efor the
purchaser to easily identify the affecte dtires.
The TIN is made up of manufacturer identifica-
tio nc ode ;,t ire size =,tire typ ecode ?and
manufacturing date A.
DO T(De partment of Transportation): tire
symbol :marks thatt he tire complies with the
Alla bout wheels and tires277
Wheel sand tires
Z

requirements of the U.S. Department of Trans-
portation.
Manufacturer identificationcode: manufac-
turer identification code ;provides details on
the tire manufacturer. New tires have acode
with two symbols. Retreaded tires have acode
with four symbols.
For further informatio nabout retreaded tires,
see (
Ypag e284).
Tire size: identifier=describes the tire size.
Tire type code: tire type code?can be used by
the manufacturer as acode to describes pecific
characteristics of the tire.
Date of manufacture: date of manufactureA
provides informatio nabout the age of atire. The
first and second positions represent the weeko f
manufacture, starting with "01" for the first cal-
endar week. Positions three and four represent
the yea rofmanufacture. For example, atire that
is marked "3214" was manufactured in week3 2
in 2014.
iTire data is vehicle-specific and may deviate
from the data in the example.
Tire characteristics
This informatio ndescribes 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 compositio nand material used
Describes the number of plies or the number of
layers of rubber-coated fabricint he 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)a nd 100 kilopascals(kPa)
are the equivalent of 1bar.
DOT (Department of Transportation)
DOT-marked tires fulfill the requirements of the
USD epartment of Transportation.
Normal occupant weight
The number of occupants for which the vehicle
is designed multiplied by 68 kilograms (150 lbs).
Uniform Tire Quality Grading Standards
Auniform standard to grad ethe quality of tires
with regards to tread quality,t ire 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 moldedi nto the sidewallof
the tire.
Recommended tire pressures
The recommended tire pressure appliestot he
tires mounted at the factory.
The Tire and Loading Information placard con-
tains the recommended tire pressures for cold
tires on afullyloaded vehiclea nd for the maxi-
mum permissiblev ehiclespeed.
The tire pressure table contains the recommen-
ded pressures for cold tires for various operat-
ing conditions, i.e. differing loada nd speedcon-
ditions.
Increased vehicle weight due to optional
equipment
The combined weight of all standard and
optionale quipment available for the vehicle,
regardless of whetheritisa ctually installed on
the vehicleorn ot.
Rim
This is the part of the wheelonw hich the tire is
mounted.
GAWR (Gross Axl eWeight Rating)
The GAWR is the maximu mgross axle weight
rating. The actua lloadonana xle 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 dri
ver's
side.
278Alla bout wheels and tires
Wheels and tires

Weight of optional extras
The combined weight of those optionalextras
that weigh more than the replaced standard
parts and more than 2.3 kg (5 lbs).T hese
optionale xtras, such as high-performance
brakes ,levelc ontrol, aroof rack or ahigh-per-
formance battery,a re not included in the curb
weight and the weight of the accessories.
TIN (Tire Identification Number)
This is aunique identifier which can be use dby
at ire manufacturer to identify tires, for example
for aproduct 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 bearin gindex
The loadb earing index (also loadi ndex) isacode
that contains the maximu mloadb earing capa-
city of atire.
Traction
Tractio nisthe result of friction between the tires
and the road surface.
Treadwear indicators
Narrow bars (tread wearb ars)that are distrib-
uted over the tire tread. If the tire tread is level
with the bars ,the wearl imitofá in (1.6 mm)
has been reached.
Occupant distribution
The distribution of occupants in avehicleatt heir
designated seating positions.
Total load limit
Nominall oadand luggagel oadplus68kg
(150 lbs) multiplied by the number of seats in
the vehicle.
Changing awheel
Flat tire
The "Breakdown assistance" section
(Ypage2 46) contains information and notes on
how to dealw ithaflat tire. Informatio nondriv-
ing with MOExtended tires in the event of aflat
tire can be found under "MOExtended tires (tires
with run-fla tcharacteristics" (
Ypage2 47).
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 wheelb rakes or suspension components
may als obedamaged. There is arisk of acci-
dent.
Rotate front and rear wheels only if the wheels and tires are of the same dimensions.
!On vehicles equipped with atire pressure
monitor, electronic components are located
in the wheel.
Tire-mounting tools should not be use dnear
the valve .This coul ddamage the electronic
components.
Only have tires changed at aqualified spe-
cialist workshop.
Always pay attention to the instructions and
safety notes when changing awheel
(
Ypage2 81).
The wearp atterns on the front and rear tires
differ, depending on the operating conditions.
Rotate the wheels before aclearw earp attern
has formed on the tires. Front tires typically
wearm ore 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 interval sinthe tire manufacturer's
warranty book in you rvehicled ocuments. If no
warranty book is available,t he tires should be
rotated every 3,000 to 6,000 mile s(5,000 to
10,000 km) .Depending on tire wear, this may
be required earlier. Do not change the direction
of wheelr otation.
Clean the contact surfaces of the wheela nd the
brake disc thoroughly every time awhee lisr ota-
ted. Check the tire pressure and, if necessary,
restart the tire pressure loss warning system or
the tire pressure monitor.
Directio nofrotation
Tires with aspecified direction of rotation have
additionalb enefits, e.g. if there is arisk of hydro-
planing. These advantages can only be gained if
the tires are installed corresponding to the
direction of rotation.
280Changing awheel
Wheels and tires