wheels MERCEDES-BENZ E-Class CABRIOLET 2017 A207 Service Manual

Important notes on tire pressure
GWARNING
If th etire pressur edrops repeatedly, th e
wheel, valv eor tire may be damaged. Tir e
pressur ethat is to olow may result in atire
blow-out .Ther eis aris kof an accident.
RChec kth etire for foreign objects .
RCheckwhether th ewhee lis losing air or th e
valv eis leaking .
If you are unable to rectify th edamage, con-
tac t a qualified specialist workshop.
GWARNIN G
If you fit unsuitable accessories onto tire
valves, th etire valves may be overloaded and
malfunction ,whic hcan caus etire pressur e
loss .Due to their design ,retrofitte dtire pres-
sur emonitors keep th etire valv eopen .This
can also result in tire pressur eloss .Ther eis a
ris kof an accident.
Only screw th estandard valv ecap or other
valv ecap sapprove dby Mercedes-Ben zfor
your vehicl eonto th etire valve.
Use asuitable pressur egauge to chec kth etire
pressure. The outer appearanc eof atire does
no tpermit any reliable conclusio nabout th etire
pressure. On vehicles equipped wit hth eelec -
tronic tire pressur emonitor, th etire pressur e
can be checke din th eon-board computer.
The tire temperature and pressur eincreas e
when th evehicl eis in motion .This is dependen t
on th edriving spee dand th eload.
Therefore, you should only correc ttire pres-
sures when th etires are cold.
The tires are cold:
Rif th evehicl ehas been parked wit hth etires
out of direct sunligh tfor at least three hour s
and
Rif th evehicl ehas no tbeen driven further than
1 mile (1. 6km)
The tire temperature changes depending on th e
outside temperature, th evehicl espee dand th e
tire l
oad. If th etire temperature changes by
18 ‡(10 †), th etire pressur echanges by
approximately 10 kP a(0. 1bar/1.5 psi) .Tak e
this int oaccoun twhen checkin gth epressur eof
warm tires .Only correc tth etire pressur eif it is to
olow for th ecurren toperating conditions. If
you chec kth etire pressur ewhen th etires are
warm ,th eresulting value will be higher than if
th etires were cold. This is normal. Do no t
reduce th etire pressur eto th evalue specifie d
for cold tires .The tire pressur ewould otherwise
be to olow.
Observ eth erecommended tire pressures for
cold tires :
Ron theTir eand Loading Information placard
on th eB-pillar on th edriver' sside
Rin th etire pressur etable on th efuel filler flap
(Ypage 142)
Underinflated or overinflated tires
Underinflated tires
GWARNIN G
Tires wit hpressur ethat is to olow can over-
heat and burs tas aconsequence .In addition ,
they also suffer from excessiv eand/o rirreg-
ular wear ,whic hcan severely impair th ebrak -
ing properties and th edriving characteristics .
Ther eis aris kof an accident.
Avoid tire pressures that are to olow in all th e
tires ,includin gth espar ewheel.
Underinflated tires may:
Roverheat, leadin gto tire defects
Radversely affec thandlin g
Rwear excessively and/o runevenly
Rhav ean adverse effec ton fuel consumption
Overinflated tires
GWARNIN G
Tires wit hexcessively high pressur ecan burs t
because they are damaged mor eeasil yby
road debris, pothole setc. In addition ,they
also suffer from irregular wear ,whic hcan
severely impair th ebraking properties and th e
driving characteristics .Ther eis aris kof an
accident.
Avoid tire pressures that are to ohigh in all th e
tires ,includin gth espar ewheel.
290Tire pressure
Wheels and tires

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.
Checking the tire pressures
Important safety notes
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
Rin the tire pressure table in the fuel filler flap
(Ypage 142)
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 Service
menu of the multifunction
display, see illustration (example).
For information on the message display, refer to
the "Checking the tire pressure electronically"
section (
Ypage 293).
Tire pressure291
Wheels and tires
Z

Important safety notes
GWARNING
Eac htire, includin gth espar e(if provided),
should be checke dat least once amonth
when cold and inflated to th epressur erec -
ommended by th evehicl emanufacturer on
th eTir eand Loading Information placard on
th edriver' sdoor B-pillar or th etire pressur e
label on th einside of th efuel filler flap .If your
vehicl ehas tires of adifferen tsiz ethan th e
siz eindicated on th eTir eand Loading Infor -
mation placard or th etire pressur elabel, you
should determine th eproper tire pressur efor
those tires .
As an added safet yfeature, your vehicl ehas
been equipped wit h atire pressur emonitoring
system (TPMS) that illuminate s alow tire pres-
sur etelltale when on eor mor eof your tires
are significantly underinflated. Accordingly,
when th elow tire pressur etelltale illuminates,
you should stop and chec kyour tires as soo n
as possible ,and inflat ethem to th eproper
pressure. Drivin gon asignificantly underin-
flated tire causes th etire to overheat and can
lead to tire failure. Underinflation also
reduce sfuel efficiency and tire tread life ,and
may affec tth evehicle's handlin gand stop-
pin gability.
Pleas enote that th eTPM Sis no t asubstitut e
for proper tire maintenance ,a
nd it is th edriv -
er' sresponsibilit yto maintai ncorrec ttire
pressure, eve nif underinflation has no t
reached th elevel to trigge rillumination of th e
TPM Slow tire pressur etelltale.
Your vehicl ehas also been equipped wit h a
TPM Smalfunction indicator to indicat eif th e
system is no toperating properly. The TPM S
malfunction indicator is combined wit hth e
low tire pressur etelltale. When th esystem
detects amalfunction ,th ewarning lamp will
flas hfor approximately aminute and then
remain continuously illuminated. This
sequenc ewill be repeated every time th evehi-
cle is started as lon gas th emalfunction
exists.
When th emalfunction indicator is illuminated,
th esystem may no tbe able to detec tor signal
low tire pressur eas intended. TPM Smalfunc -
tion smay occur for avariet yof reasons,
includin gth einstallation of incompatible
replacemen tor alternate tires or wheels on
th evehicl ethat preven tth eTPM Sfrom func-
tioning properly. Always chec kth eTPM Smal-
function telltale after replacing on eor mor e
tires or wheels on your vehicl eto ensur ethat
th ereplacemen tor alternate tires and wheels
allow th eTPM Sto continue to function prop-
erly.
It is th edriver' sresponsibilit yto set th etire
pressur eto that recommended for cold tires
whic his suitable for th eoperating situation
(
Ypage 288). Not ethat th ecorrec ttire pressur e
for th ecurren toperating situation must first be
taught-in to th etire pressur emonitor. If there is
a substantial loss of pressure, th ewarning
threshold for th ewarning message is aligned to
th ereferenc evalue staught-in .Restart th etire
pressur emonitor after adjusting th epressur eof
th ecold tires (
Ypage 293). The curren tpres-
sures are saved as ne wreferenc evalues. As a
result , awarning message will appear if th etire
pre ssur
ed
rops significantly.
The tire pressur emonitor does no twarn you of
an incorrectl yset tire pressure. Observ eth e
note son th erecommended tire pressur e
(
Ypage 288).
The tire pressur emonitor is no table to warn you
of asudde nloss of pressure, e.g. if th etire is
penetrated by aforeign object. In th eevent of a
sudde nloss of pressure, brin gth evehicl eto a
halt by braking carefully. Avoid abrup tsteering
movements.
The tire pressur emonitor has ayellow warning
lamp in th einstrumen tcluste rfor indicating
pressur eloss or amalfunction .Whether th e
warning lamp flashes or lights up indicates
whether atire pressur eis to olow or th etire
pressur emonitor is malfunctioning :
Rif thewarning lamp is lit continuously, th etire
pressur eon on eor mor etires is significantly
to olow. The tire pressur emonitor is no tmal-
functioning .
Rif thewarning lamp flashes for aroun d a
minute and then remain slit constantly, th e
tire pressur emonitor is malfunctioning .
292Tire pressure
Wheels and tires

In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(
Ypage 219).
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 gauge. 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 gauge 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
in the ignition lock (Ypage 128).
XPress the =or; button on the steering
wheel to select the Servicemenu.
XPress the9or: button to select
Tire Pressure.
XPress the abutton.
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 pressures 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.
If an emergency spare wheel is mounted, the
system may continue to show the tire pressure of the wheel that has been removed for a few
minutes. If this occurs, note that the value dis-
played for the position where the spare wheel is
mounted is not the same as the current tire
pressure of the emergency spare wheel.
Tire pressure monitor warning mes-
sages
If the tire pressure monitor detects a pressure
loss in one or more tires, a warning message is
shown in the multifunction display. The yellow
tire pressure warning lamp then lights up.
RIf the 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 oppor-
tunity arises.
RIf the Check Tiresmessage appears in the
multifunction display, the tire pressure in one
or more tires has dropped significantly. The
tires must be checked.
RIf the WarningTireMalfunctionmessage
appears in the multifunction display, the tire
pressure in one or more tires is dropping sud-
denly. The tires must be checked.
Observe the instructions and safety notes in the
display messages in the "Tires" section
(
Ypage 219).
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 define refer-
ence 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).
Tire pressure293
Wheels and tires
Z

You can find more tire pressure values for
various operating conditions in the tire pres-
sure table inside the fuel filler flap
(
Ypage 288).
XMake sure that the tire pressure is correct on
all four wheels.
XMake sure that the SmartKey is in position2
in the ignition lock.
XPress the =or; button on the steering
wheel to select the Servicemenu.
XPress the9or: button to select
Tire Pressure.
XPress the abutton.
The multifunction display shows the current
tire pressure for the individual tires or the
Tire pressures 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 the abutton.
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 %button.
The tire pressure values stored at the last
restart will continue to be monitored.
Loading the vehicle
Instruction labels for tires and loads
GWARNING
Overloaded tires can overheat, causing a
blowout. Overloaded tires can also impair the steering and driving characteristics and lead
to brake failure. There is a risk of accident.
Observe the load rating of the tires. The load
rating must be at least half of the GAWR of
your vehicle. Never overload the tires by
exceeding the maximum load. Two instruction labels on your vehicle show the
maximum possible load.
(1) The Tire and Loading Information placard is on the B-pillar on the driver's side. The Tire
and Loading Information placard shows the
maximum permissible number of occu-
pants and the maximum permissible vehicle
load. It also contains details of the tire sizes
and corresponding pressures for tires
mounted at the factory.
(2) The vehicle identification plate is on the B- pillar on the driver's side. The vehicle iden-
tification plate informs you of the gross
vehicle weight rating. It is made up of the
vehicle weight, all vehicle occupants, the
fuel and the cargo. You can also find infor-
mation about the maximum gross axle
weight rating on the front and rear axle.
The maximum gross axle weight rating is
the maximum weight that can be carried by
one axle (front or rear axle). Never exceed
the maximum load or the maximum gross
axle weight rating for the front or rear axle.
:B-pillar, driver's side
Maximum permissible gross vehicle
weight rating
294Loading the vehicle
Wheels and tires

XSpecification for maximum gross vehicle
weight:is listed in the Tire and Loading
Information placard: "The combined weight of occupants and cargo should never exceed
XXX kilograms or XXX lbs."
The gross weight of all vehicle occupants, load
and luggage must not exceed the specified
value.
iThe specifications shown on the Tire and
Loading Information placard in the illustration are examples. The maximum permissible
gross vehicle weight rating is vehicle-specific
and may differ from that in the illustration.
You can find the valid maximum permissible
gross vehicle weight rating for your vehicle on
the Tire and Loading Information placard.
Number of seats
Maximum number of seats :indicates the
maximum number of occupants allowed to
travel in the vehicle. This information can be
found on the Tire and Loading Information plac-
ard.
iThe specifications shown on the Tire and
Loading Information placard in the illustration
are examples. The number of seats is vehicle-
specific and can differ from the details shown.
The number of seats in your vehicle can be
found on the Tire and Loading Information
placard.
Determining the correct load limit
Step-by-step instructions
The following steps have been developed as
required of all manufacturers under Title 49,
Code of U.S. Federal Regulations, Part 575 pur- suant to the "National Traffic and 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 your vehicle’s
Tire and Loading Information placard.
XStep 2: Determine the combined weight of
the driver and passengers that will be riding in your vehicle.
XStep 3: Subtract the combined weight of the
driver and passengers from XXX kilograms or
XXX lbs.
XStep 4: The resulting figure equals the avail-
able amount of cargo and luggage load capa-
city. For example, if the "XXX" amount equals
1400 lbs and there will be five 150-lb pas-
sengers in your vehicle, the amount of avail-
able cargo and luggage load capacity is
650 lbs (1400 - 750 (5 x 150) = 650 lbs).
XStep 5: Determine the combined weight of
luggage and cargo being loaded on the vehi-
cle. That weight may not safely exceed the
available cargo and luggage load capacity cal- culated in step 4.
Loading the vehicle295
Wheels and tires
Z

Example: steps 1 to 3
The following table shows examples on how to calculate total and cargo load capacities with varying
seating configurations and number and size of occupants. The following examples use a load limit of
1500 lbs (680 kg).This is for illustration purposes only. Make sure you are using the actual load
limit for your vehicle stated on your vehicle's Tire and Loading Information placard (
Ypage 294).
The greater the combined weight of the occupants, the lower the maximum luggage load.
Step 1
Example 1Example 2Example 3
Combined maximum
weight of occupants
and cargo (data from
the Tire and Loading
Information placard)1500 lbs (680 kg)1500 lbs (680 kg)1500 lbs (680 kg)
Step 2
Example 1Example 2Example 3
Number of people in
the vehicle (driver and
occupants)531
Distribution of the
occupantsFront: 2
Rear: 3Front: 1
Rear: 2Front: 1
Weight of the occu-
pantsOccupant 1: 150 lbs
(68 kg)
Occupant 2: 180 lbs
(82 kg)
Occupant 3: 160 lbs
(73 kg)
Occupant 4: 140 lbs
(63 kg)
Occupant 5: 120 lbs
(54 kg)Occupant 1: 200 lbs
(91 kg)
Occupant 2: 190 lbs
(86 kg)
Occupant 3: 150 lbs
(68 kg)Occupant 1: 150 lbs
(68 kg)
Gross weight of all
occupants750 lbs (340 kg)540 lbs (245 kg)150 lbs (68 kg)
Step 3
Example 1Example 2Example 3
Permissible load (maxi-
mum gross vehicle
weight rating from the
Tire and Loading Infor-
mation placard minus
the gross weight of all
occupants)1500 lbs (680 kg) Ò
750 lbs (340 kg) =
750 lbs (340 kg)1500 lbs (680 kg) Ò
540 lbs (245 kg)
=960 lbs (435 kg)1500 lbs (680 kg) Ò
150 lbs (68 kg) =
1350 lbs (612 kg)
296Loading the vehicle
Wheels and tires

Vehicle identification plate
Even if you have calculated the total cargo care-
fully, you should still make sure that the gross
vehicle weight rating and the gross axle weight
rating are not exceeded. Details can be found on
the vehicle identification plate on the B-pillar on
the driver's side of the vehicle (
Ypage 294).
Permissible Gross Vehicle Weight Rating
(GVWR): the gross weight of the vehicle, all pas-
sengers, load and trailer load/noseweight (if
applicable) must not exceed the permissible
gross vehicle weight.
Gross Axle Weight Rating (GAWR): the maxi-
mum permissible weight that can be carried by
one axle (front or rear axle).
To ensure that your vehicle does not exceed the
maximum permissible values (gross vehicle
weight and maximum gross axle weight rating),
have your loaded vehicle (including driver, occu-
pants, cargo, and full trailer load if applicable)
weighed on a suitable vehicle weighbridge.
All about wheels and tires
Uniform Tire Quality Grading Stand-
ards
Overview of Tire Quality Grading Stand-
ards
Uniform Tire Quality Grading Standards are U.S.
government specifications. Their purpose is to
provide drivers with uniform reliable information
on tire performance data. Tire manufacturers
have to grade tires using three performance fac- tors: :tread wear grade, ;traction grade and
= temperature grade. These regulations do not
apply to Canada. Nevertheless, all tires sold in
North America are provided with the corre- sponding quality grading markings on the side-
wall of the tire.
Quality grades can be found, where applicable,
on the tire sidewall between tread shoulder and
maximum section width.
Example:
RTreadwear grade:
200
RTraction grade:AA
RTemperature grade: A
All passenger car tires must conform to the stat-
utory safety requirements in addition to these
grades.
iThe actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified U.S.
government course. For example, a tire graded
150 would wear one and one-half times as well
on the government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, however, and
may depart significantly from the norm due to
variations in driving habits, service practices
and differences in road characteristics and cli-
mate.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
!Avoid wheelspin. This can lead to damage to
the drive train.
The traction grades – from highest to lowest –
are AA, A, B and C. Those grades represent the
tire's ability to stop on wet pavement as meas-
ured under controlled conditions on specified
government test surfaces of asphalt and con-
crete. A tire marked C may have poor traction
performance.
The safe speed on a wet, snow covered or icy
road is always lower than on dry road surfaces.
All about wheels and tires297
Wheels and tires
Z

You should pay special attention to road condi-
tions when temperatures are around freezing
point.
Mercedes-Benz recommends a minimum tread
depth ofãin (4 mm) on all four winter tires.
Observe the legally required minimum tire tread
depth (
Ypage 286). Winter tires can reduce the
braking distance on snow-covered surfaces in
comparison with summer tires. The braking dis-
tance is still much further than on surfaces that
are not icy or covered with snow. Take appro-
priate care when driving.
Further information on winter tires (M+S tires)
(
Ypage 287).
Temperature
GWARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, underinfla-
tion, or excessive loading, either separately or
in combination, can cause excessive heat
build-up and possible tire failure.
The temperature grades are A (the highest), B,
and C, representing the tire's resistance to the
generation of heat and its ability to dissipate
heat when tested under controlled conditions
on a specified indoor laboratory test wheel. Sus-
tained high temperature can cause the material
of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of
performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A represent
higher levels of performance on the laboratory
test wheel than the minimum required by law.
Tire labeling
Overview
:Uniform Tire Quality Grading Standards
(Ypage 301)
;Department of Transportation, Tire Identifi-
cation Number (Ypage 301)
=Maximum load rating (Ypage 300)
?Maximum tire pressures (Ypage 291)
AManufacturer
BTire material (Ypage 301)
CTire size designation, load-bearing capacity
and speed rating (Ypage 298)
DLoad index (Ypage 300)
ETire name
The markings described above are on the tire in
addition to the tire name (sales designation) and
the manufacturer's name.
iTire data is vehicle-specific and may deviate
from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
GWARNING
Exceeding the stated tire load-bearing capa-
city and the approved maximum speed could
lead to tire damage or the tire bursting. There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
298All about wheels and tires
Wheels and tires

tire load rating and speed rating required for
your vehicle.
:Tire width
;Nominal aspect ratio in %
=Tire code
?Rim diameter
ALoad bearing index
BSpeed rating
General: depending on the manufacturer's
standards, the size imprinted in the tire wall may
not contain any letters or may contain one letter
that precedes the size description.
If there is no letter preceding the size descrip-
tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S. man-
ufacturing standards.
If "LT" precedes the size description: these are
light truck tires according to U.S. manufacturing
standards.
If "T" precedes the size description: compact
emergency wheels with high tire pressure that
are only designed for temporary use in an emer-
gency.
Tire width: tire width:shows the nominal tire
width in millimeters.
Aspect ratio: aspect ratio;is the size ratio
between the tire height and tire width and is
shown in percent. The aspect ratio is calculated
by dividing the tire width by the tire height.
Tire code: tire code=specifies the tire type.
"R" represents radial tires; "D" represents diag-
onal tires
; "B" represents diagonal radial tires.
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 capacity of a tire.
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 294).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can bear.
For further information on the maximum tire
load in kilograms and lbs, see (
Ypage 300).
For further information on the load bearing
index, see "Load index" (
Ypage 300).
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. Drive carefully 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 with a maximum speed of
over 149 mph (240 km/h) may have "ZR" in
the size description, depending on the man-
ufacturer (e.g. 245/40 ZR 18).
RIf a service specification is available, the max-
imum speed is limited according to the speed
All about wheels an d tires299
Wheels and tires
Z