2007 MERCEDES-BENZ S CLASS tire size

519 Operation
Tires and wheels
General:
Depending on the design standards used,
the tire size molded into the sidewall may
have no letter or a letter preceding the tire
size designation.
No letter preceding the size designation
(as illustrated above): Passenger car tire
based on European design standards.
Letter “P” preceding the size designation:
Passenger car tire based on U.S. design
standards.
Letter “LT” preceding the size designation:
Light Truck tire based on U.S. design
standards.
Letter “T” preceding the size designation:
Temporary spare tires which are high
pressure compact spares designed for
temporary emergency use only. Tire width
The tire width1 (
page 518) indicates
the nominal tire width in mm.
Aspect ratio
The aspect ratio2 (page 518) is the
dimensional relationship between tire
section height and section width and is
expressed in percentage. The aspect ratio
is arrived at by dividing section height by
section width.
Tire code
The tire code3 (
page 518) indicates
the tire construction type. The “R” stands
for radial tire type. Letter “D” means diag-
onal or bias ply construction; letter “B”
means belted-bias ply construction.
At the tire manufacturer’s option, any tire
with a speed capability above 149 mph
(240 km/h) can include a “ZR” in the size
designation (for example: 245/40 ZR 18).
For additional information, see “Tire speed
rating” (
page 520).Rim diameter
The rim diameter4 (
page 518) is the
diameter of the bead seat, not the
diameter of the rim edge. Rim diameter is
indicated in inches (in).
Tire load rating
The tire load rating5 (page 518) is a
numerical code associated with the
maximum load a tire can support.
For example, a load rating of 91 corre-
sponds to a maximum load of 1 356 lbs
(615 kg) the tire is designed to support.
See also “Maximum tire load”
(
page 523) where the maximum load as-
sociated with the load index is indicated in
kilograms and lbs.

520 OperationTires and wheels
For additional information on tire load
rating, see “Load identification”
(page 521).
Tire speed rating
The tire speed rating6 (
page 518)
indicates the approved maximum speed
for the tire.Summer tires


At the tire manufacturer’s option, any
tire with a speed capability above
149 mph (240 km/h) can include a
“ZR” in the size designation (for exam-
ple: 245/40 ZR18). To determine the
maximum speed capability of the tire,
Warning!
G
The tire load rating must always be at least
half of the GAWR (
page 526) of your vehi-
cle. Otherwise, tire failure may be the result
which may cause an accident and/or seri-
ous personal injury to you or others.
Always replace rims and tires with the same
designation, manufacturer and type as
shown on the original part.
Warning!
G
Do not overload the tires by exceeding the
specified load limit or vehicle capacity
weight as indicated on the placard located
on the driver’s door B-pillar (
page 503).
Overloading the tires can overheat them,
possibly causing a blowout. Overloading the
tires can also result in handling or steering
problems, or brake failure.
i
Tire load rating5 (
page 518) and tire
speed rating6 (
page 518) are also referred
to as “service description”.
Warning!
G
Even when permitted by law, never operate
a vehicle at speeds greater than the
maximum speed rating of the tires.
Exceeding the maximum speed for which
tires are rated can lead to sudden tire
failure, causing loss of vehicle control and
possibly resulting in an accident and/or
personal injury and possible death, for you
and for others.
i
Tire load rating5 (
page 518) and tire
speed rating6 (
page 518) are also referred
to as “service description”.
Index
Speed rating
Q
up to 100 mph (160 km/h)
R
up to 106 mph (170 km/h)
S
up to 112 mph (180 km/h)
T
up to 118 mph (190 km/h)
H
up to 130 mph (210 km/h)
V
up to 149 mph (240 km/h)
W
up to 168 mph (270 km/h)
Y
up to 186 mph (300 km/h)
(Y)
above 186 mph (300 km/h)
ZR
above 149 mph (240 km/h)

521 Operation
Tires and wheels
the service description for the tire must
be referred to. The service description
is comprised of the tire load rating5
(page 518) and the tire speed
rating6 (
page 518).
If your tire includes “ZR” in the size
designation and no service
description5 and6 (
page 518) is
given, the tire manufacturer must be
consulted for the maximum speed ca-
pability.
If a service description5 and6
(
page 518) is given, the speed capa-
bility is limited by the speed symbol in
the service description.
Example: 245/40 ZR18 97Y.
In this example, “97Y” is the service
description. The letter “Y” designates
the speed rating and the speed capabil-
ity of the tire is limited to 186 mph
(300 km/h).


Any tire with a speed capability above
186 mph (300 km/h) must include a
“ZR” in the size designation AND the
service description must be placed in
parenthesis.
Example: 275/40 ZR 18 (99Y).
The “(Y)” speed rating in parenthesis
designates the maximum speed capa-
bility of the tire as being above
186 mph (300 km/h). Consult the tire
manufacturer for the actual maximum
permissible speed of the tire.
All-season and winter tires
Load identification
1Load identification
Index
Speed rating
QM+S
1
1or M+S.for winter tires
up to 100 mph (160 km/h)
TM+S
1
up to 118 mph (190 km/h)
HM+S
1
up to 130 mph (210 km/h)
VM+S
1
up to 149 mph (240 km/h)
i
Not all M+S rated tires provide special win-
ter performance. Make sure the tires you use
show M+S and the mountain/snow-
flake.
marking on the tire sidewall. These
tires meet specific snow traction performance
requirements of the Rubber Manufacturers As-
sociation (RMA) and the Rubber Association of
Canada (RAC) and have been designed specifi-
cally for use in snow conditions.
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

522 OperationTires and wheelsIn addition to tire load rating, special load
information may be molded into the tire
sidewall following the letter designating
the tire speed rating6 (
page 518).
No specification given: absence of any text
(like in above example) indicates a
standard load (SL) tire.
XL (Extra Load): designates an extra load
(or reinforced) tire.
Light Load: designates a light load tire.
C, D, E: designates load range associated
with the maximum load a tire can carry at
a specified pressure.
DOT, Tire Identification Number (TIN)
U.S. tire regulations require each new tire
manufacturer or tire retreader to mold a
TIN into or onto a sidewall of each tire
produced.
The TIN is a unique identifier which facili-
tates efforts by tire manufactures to notify
purchasers in recall situations or other safety matters concerning tires and gives
purchasers the means to easily identify
such tires.
The TIN is comprised of “Manufacturer’s
identification mark”, “Tire size”, “Tire type
code” and “Date of manufacture”.
1DOT
2Manufacturer’s identification mark
3Tire size
4Tire type code (at the option of the tire
manufacturer)
5Date of manufactureDOT (D
epartment o
f T
ransportation)
A tire branding symbol1 (
page 522)
which denotes the tire meets require-
ments of the U.S. Department of Transpor-
tation.
Manufacturer’s identification mark
The manufacturer’s identification mark2
(
page 522) denotes the tire
manufacturer.
New tires have a mark with two symbols.
Retreaded tires have a mark with four sym-
bols. For more information on retreaded
tires (
page 500).
Tire size
The code3 (
page 522) indicates the
tire size.
Tire type code
The code4 (page 522) may, at the
option of the manufacturer, be used as a
descriptive code for identifying significant
characteristics of the tire.
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

528 OperationTires and wheelsconcerning tires and gives purchases the
means to easily identify such tires. The TIN
is comprised of “Manufacturer’s identifica-
tion mark”, “Tire size”, “Tire type code”
and “Date of manufacture”.
Tire load rating
Numerical code associated with the
maximum load a tire can support.
Tire ply composition and material used
This indicates the number of plies or the
number of layers of rubber-coated fabric in
the tire tread and sidewall. Tire manufac-
turers also must indicate the ply materials
in the tire and sidewall, which include
steel, nylon, polyester, and others.
Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is approved.Traction
Force exerted by the vehicle on the road
via the tires. The amount of grip provided.
Tread
The portion of a tire that comes into
contact with the road.
Treadwear indicators
Narrow bands, sometimes called
“wear bars” that show across the tread of
a tire when only
1/16
in (1.6 mm) of tread
remains.
Uniform Tire Quality Grading Standards
A tire information system that provides
consumers with ratings for a tire’s traction,
temperature and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The
ratings are molded into the sidewall of the
tire.Vehicle capacity weight
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle’s
designated seating capacity.
Vehicle maximum load on the tire
Load on an individual tire that is
determined by distributing to each axle its
share of the maximum loaded vehicle
weight and dividing it by two.

529 Operation
Tires and wheels
Rotating tires
Tire rotation can be performed on vehicles
with tires of the same dimension all
around. If your vehicle is equipped with
tires of the same dimension all around,
tires can be rotated, observing a
front-to-rear rotation pattern that will
maintain the intended rotation (spinning)
direction of the tire (
page 503).
In some cases, such as when your vehicle
is equipped with mixed-size tires (different
tire dimension front vs. rear), tire rotation
is not possible.If applicable to your vehicle’s tire configu-
ration, tires can be rotated according to
the tire manufacturer’s recommended in-
tervals in the tire manufacturer’s warranty
pamphlet located in your vehicle literature
portfolio. If none is available, tires should
be rotated every 3 000 to 6 000 miles
(5 000 to 10 000 km), or sooner if neces-
sary, according to the degree of tire wear.
The same rotation (spinning) direction
must be maintained (
page 503).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
Thoroughly clean the mounting face of
wheels and brake disks, i.e. the inner side
of the wheels/tires, during each rotation.
Check for and ensure proper tire inflation
pressure.For information on wheel change, see the
“Practical hints” section (
page 629).
Warning!
G
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs.
rear), tire rotation is not possible.
Warning!
G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
110 lb-ft (150 Nm).
Only use Genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.

531 Operation
Winter driving
Snow chains
Snow chains should only be driven on
snow-covered roads at speeds not to
exceed 30 mph (50 km/h). Remove chains
as soon as possible when driving on roads
without snow.Please observe the following guidelines
when using snow chains:


Use of snow chains is not permissible
with all wheel/tire combinations.


Snow chains should only be used on
the rear wheels. Follow the manufac-
turer’s mounting instructions.


Only use snow chains that are
approved by Mercedes-Benz. Your
authorized Mercedes-Benz Center will
be glad to advise you on this subject.


Use of snow chains may be prohibited
depending on location. Always check
local and state laws before installing
snow chains.
!
When driving with snow chains, always se-
lect the raised level of the level control system
Airmatic* (
page 401). Other settings may re-
sult in damage to your vehicle.
i
When driving with snow chains, you may
wish to deactivate the ESP
® (page 73) before
setting the vehicle in motion. This will improve
the vehicle’s traction.
!
Some tire sizes do not leave adequate clear-
ance for snow chains. To help avoid serious dam-
age to your vehicle or tires, use of snow chains is
not permissible with the spare wheel.
For use of snow chains on tire size
255/45 R18 99H M+S
.
, contact an autho-
rized Mercedes-Benz Center.

554 Practical hintsWhat to do if …?Warning!
G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
vehicle placard or the tire inflation pressure
label. (If your vehicle has tires of a different
size than the size indicated on the vehicle
placard or the tire inflation pressure label,
you should determine the proper tire infla-
tion pressure for those tires).
As an added safety feature, your vehicle has
been equipped with a tire pressure monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires is significantly under-inflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a significant-
ly under-inflated tire causes the tire to over-
heat and can lead to tire failure.
Under-inflation also reduces fuel efficiency
and tire tread life, and may affect the vehi-
cle’s handling and stopping ability. Please
note that the TPMS is not a substitute for
proper tire maintenance, and it is the driv-
er’s responsibility to maintain correct tire
pressure, even if under-inflation has not
reached the level to trigger illumination of
the TPMS low tire pressure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate
when the system is not operating properly.
The TPMS malfunction indicator is com-
bined with the low tire pressure telltale.
When the system detects a malfunction, the
telltale will flash for approximately
one minute and then remain continuously
illuminated. This sequence will continue
upon subsequent vehicle start-ups as long
as the malfunction exists. When the mal-
function indicator is illuminated, the system
may not be able to detect or signal low tire
pressure as intended.
TPMS malfunctions may occur for a variety
of reasons, including the installation of
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from
functioning properly. Always check the
TPMS malfunction 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 properly.