2008 SMART FORTWO COUPE tires
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Tires and wheels
196
>> Operation
Tire labelingBesides tire name (sales designation) and
manufacturer name, a number of markings can
be found on a tire.
Following are some explanations for the mark
ings on your vehicle’s tires:
1
Uniform Quality Grading Standards
(page 202)
2
DOT, Tire Identification Number (TIN)
(page 200)
3
Maximum tire load (
page 201)
4
Maximum tire inflation pressure
(page 202)
5
Manufacturer
6
Tire ply material (
page 204)
7
Tire size designation, load and speed
rating (
page 196)
8
Load identification (
page 200)
9
Tire name
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
For more information, see "Rims and
tires"(
page 299).Tire size designation, load and speed rating
1
Tire width
2
Aspect ratio in %
3
Radial tire code
4
Rim diameter
5
Tire load rating
6
Tire speed rating
i
For information purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
Page 198 of 314
Tires and wheels
>> Operation
197
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 des
ignation.
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
Tire width1
(page 196) indicates the
nominal tire width in mm.Aspect ratio
Aspect ratio2
(page 196) is the dimen
sional 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
Tire code3 (
page 196) indicates the tire
construction type. The "R" stands for radial
tire type. Letter "D" means diagonal 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 198)
.
Rim diameter
Rim diameter4 (
page 196) is the diameter
of the bead seat, not the diameter of the rim
edge. Rim diameter is indicated in inches (in).Tire load rating
Tire load rating5 (
page 196) is a numeri
cal code associated with the maximum load a
tire can support.
For example, a load rating of 91 corresponds
to a maximum load of 1 356 lbs (615 kg) the
tire is designed to support.
See also "Maximum tire load" (
page 201)
where the maximum load associated with the
load index is indicated in kilograms and lbs.
G
Warning!
The tire load rating must always be at
least half of the GAWR (
page 205) of
your vehicle. Otherwise, tire failure may
result and 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.
Page 199 of 314
Tires and wheels
198
>> Operation
i
Tire load rating5 (
page 196) and
Tire speed rating6 (
page 196) are also
referred to as "service description".
For additional information on tire load rating,
see "Load identification" (page 200).Tire speed rating
Tire speed rating6 (
page 196) indicates
the approved maximum speed for the tire.
i
Tire load rating5 (
page 196) and
Tire speed rating6 (
page 196) are also
referred to as "service description".Summer tires
G
Warning!
Do not overload the tires by exceeding
the specified load limit as indicated on
the Tire and Loading Information placard
located on the driver’s door Bpillar.
Overloading the tires can overheat them,
possibly causing a blowout. Overloading
the tires can also result in handling or
steering problems, or brake failure.
G
Warning!
Even when permitted by law, never oper
ate 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.
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)
Page 200 of 314
Tires and wheels
>> Operation
199
• 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 ZR18). To
determine the maximum speed capability of
the tire, the service description for the tire
must be referred to. The service descrip
tion is comprised of tire load rating5
(
page 196) and tire speed rating6
(page 196).
If your tire includes "ZR" in the size
designation and no service description5
and6 (
page 196) is given, the tire
manufacturer must be consulted for the
maximum speed capability.
If a service description5 and6
(
page 196) is given, the speed capability
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 capability 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 capability of the tire as be
ing above 186 mph (300 km/h). Consult the
tire manufacturer for the actual maximum
permissible speed of the tire.Allseason and winter tires
i
Not all M+S rated tires provide special
winter performance. Make sure the tires you
use show M+S and the mountain/snowflake
marking.on the tire sidewall. These tires
meet specific snow traction performance
requirements of the Rubber Manufacturers
Association (RMA) and the Rubber Association
of Canada (RAC) and have been designed
specifically for use in snow conditions.Index
Speed rating
Q M+S
1
1 or M+S.for winter tires
up to 100 mph (160 km/h)
T M+S
1
up to 118 mph (190 km/h)
H M+S
1
up to 130 mph (210 km/h)
V M+S
1
up to 149 mph (240 km/h)
Page 201 of 314
Tires and wheels
200
>> Operation Load identification
1
Load identification
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
In addition to the tire load rating, special load
identification1 may be molded into the tire
sidewall following the letter designating the
tire speed rating (
page 196).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 speci
fied 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 facilitates
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".
1
DOT
2
Manufacturer’s identification mark
3
Tire size
4
Tire type code (at the option of the tire
manufacturer)
5
Date of manufacture
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
Page 202 of 314
Tires and wheels
>> Operation
201
DOT (D
epartment o
f T
ransportation)
Tire branding symbol1 (
page 200) which
denotes the tire meets requirements of the
U.S. Department of Transportation.
Manufacturer’s identification mark
Manufacturer’s identification mark2
(
page 200) denotes the tire manufacturer.
New tires have a mark with two symbols.
Retreaded tires have a mark with four
symbols. For more information on retreaded
tires (
page 182).
Tire size
Code3 (page 200) indicates the tire size.
Tire type code
Code4 (page 200) may, at the option of
the manufacturer, be used as a descriptive
code for identifying significant characteris
tics of the tire.
Date of manufacture
Date of manufacture5 (
page 200)
identifies the week and year of manufacture.The first two figures identify the week, start
ing with "01" to represent the first full week of
the calendar year. The second two figures
represent the year.
For example, "3202" represents the 32nd
week of 2002.
Maximum tire load
1
Maximum tire load rating
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.The maximum tire load is the maximum weight
the tires are designed to support.
For more information on tire load rating
(
page 197).
For information on calculating total and cargo
load capacities (
page 187).
G
Warning!
Do not overload the tires by exceeding
the specified load limit as indicated on
the Tire and Loading Information placard
located on the driver’s door Bpillar.
Overloading the tires can overheat them,
possibly causing a blowout. Overloading
the tires can also result in handling or
steering problems, or brake failure.
Page 203 of 314
Tires and wheels
202
>> Operation Maximum tire inflation pressure
1
Maximum permissible tire inflation
pressure
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
This is the maximum permissible tire inflation
pressure for the tire.Always follow the recommended tire inflation
pressure (
page 189) for proper tire infla
tion.Uniform Tire Quality Grading Standards
(U.S. vehicles)
Tire manufacturers are required to grade
tires based on three performance factors:
treadwear, traction and temperature resis
tance.
1
Treadwear
2
Traction
3
Temperature resistance
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.
G
Warning!
Never exceed the max. tire inflation
pressure. Follow recommended tire
inflation pressures.
Do not underinflate tires. Underinflated
tires wear excessively and/or unevenly,
adversely affect handling and fuel econ
omy, and are more likely to fail from being
overheated.
Do not overinflate tires. Overinflated
tires can adversely affect handling and
ride comfort, wear unevenly, increase
stopping distance, and result in sudden
deflation (blowout) because they are
more likely to become punctured or
damaged by road debris, potholes etc.
Page 204 of 314
Tires and wheels
>> Operation
203
Quality grades can be found, where applica
ble, on the tire sidewall between tread shoul
der and maximum section width. For example:
All passenger car tires must conform to fed
eral safety requirements in addition to these
grades.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course.
For example, a tire graded 150 would wear
one and onehalf (1
1/2) 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 climate.Traction
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
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance.
Temperature
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.Sustained 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 corre
sponds 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.
Treadwear
Traction
Temperature
200
AA
A
G
Warning!
The traction grade assigned to this tire is
based on straightahead braking trac
tion tests, and does not include acceler
ation, cornering, hydroplaning, or peak
traction characteristics.
G
Warning!
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, or excessive load
ing, either separately or in combination,
can cause excessive heat buildup and
possible tire failure.