2011 SMART FORTWO COUPE tires

Uniform Tire Quality Grading
Standards
The Uniform Tire Quality Grading is a U.S.
Government requirement designed to give
drivers consistent and reliable
information regarding tire performance.
Tire manufacturers are required to grade
tires based on three performance factors:
treadwear 0046, traction 0047, and temperature
resistance 008A. Although not a Government
of Canada requirement, all tires made for
sale in North America have these grades
branded on the sidewall.
i For illustration purposes only. Actual
data on tires are specific to each vehicle
and may vary from data shown in above
illustration.
Quality grades can be found, where
applicable, on the tire sidewall between
tread shoulder and maximum section width.
For example:
TreadwearTractionTemperature200AAA
All passenger car tires must conform to
federal 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 U.S. government test course.
For example, a tire graded 150 would wear
one and one-half (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 GWarning!
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
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
GWarning!
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, 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. Sustained
high temperature can cause the material of
the tire to degenerate and reduce tire life,
and excessive temperature can lead to
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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.
Rotating tires
GWarning!
Do not rotate front and rear wheels as they
have different dimensions, e.g. rim size,
wheel offset etc. Otherwise, the handling
can be affected and you could endanger
yourself and others.
Thoroughly clean the mounting face of the
wheels and brake discs, i.e. the inner side
of the wheels/tires each time the wheels/
tires are changed. Check for and ensure
proper tire inflation pressure.
GWarning!
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
81 lb‑ft (110 Nm).
Only use genuine smart wheel bolts
specified for your vehicle’s rims.
For information on wheel change, see “Flat
tire” ( Y page 188).
Tire labeling
Besides tire name (sales designation) and
manufacturer name, a number of markings
can be found on a tire.
Following are some explanations for the
markings on your vehicle’s tires:
0046 Uniform Quality Grading Standards
( Y page 137)0047 DOT, Tire Identification Number (TIN)
( Y page 141)008A Maximum tire load ( Y page 135)0088 Maximum tire inflation pressure
( Y page 131)0086 Manufacturer0087 Tire ply material ( Y page 142)006E Tire size designation, load and speed
rating ( Y page 139)006F Load identification ( Y page 141)0070 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” ( Y page 217).
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Tire size designation, load and speed
rating0046 Tire width0047 Aspect ratio in %008A Radial tire code0088 Rim diameter0086 Tire load rating0087 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.
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
Tire width 0046 indicates the nominal tire
width in mm.
Aspect ratio
Aspect ratio 0047 is the dimensional
relationship between tire section height
and section width and is expressed as a
percentage. The aspect ratio is arrived at
by dividing section height by section
width.
Tire code
Tire code 008A 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” ( Y page 140).
Rim diameter
Rim diameter 0088 is the diameter of the
bead seat, not the diameter of the rim edge.
Rim diameter is indicated in inches (in).
Tire load ratingGWarning!
The tire load rating must always be at least
half of the GAWR of your vehicle. Otherwise,
tire failure may result and cause an
accident and/or serious personal injury to
you or others.
Always replace rims and tires with the same
designation, manufacturer and type as
shown on the original part.
GWarning!
Do not overload the tires by exceeding the
specified load limit as indicated on the
Tire and Loading Information placard on
the driver’s door B‑pillar. Overloading the
tires can overheat them, possibly causing
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a blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.
Tire load rating 0086 is a numerical 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” ( Y page 135)
where the maximum load associated with
the load index is indicated in kilograms
and lbs.
For additional information on tire load
rating, see “Load identification”
( Y page 141).
Tire speed rating GWarning!
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.
Regardless of the tire speed rating, local
speed limits should be obeyed. Use prudent
driving speeds appropriate to prevailing
conditions.
Tire speed rating 0087 indicates the
approved maximum speed for the tire.
Summer tires
IndexSpeed ratingQup 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)IndexSpeed ratingVup to 149 mph (240 km/h)Wup to 168 mph (270 km/h)Yup to 186 mph (300 km/h)ZR...Yabove 186 mph (300 km/h)ZR...(Y)above 186 mph (300 km/h)ZRabove 149 mph (240 km/h)
R 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 description is comprised of
tire load rating 0086 and tire speed rating
0087 .
If your tire includes “ZR” in the size
designation and no service description
is given, the tire manufacturer must be
consulted for the maximum speed
capability.
If a service description 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).
R 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 being
above 186 mph (300 km/h). Consult the tire
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manufacturer for the actual maximum
permissible speed of the tire.
All-season and winter tiresIndexSpeed ratingQ M+S 15up to 100 mph (160 km/h)T M+S 15up to 118 mph (190 km/h)H M+S 15up to 130 mph (210 km/h)V M+S 15up to 149 mph (240 km/h)
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 004D 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.
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 identification 0046 may be molded into
the tire sidewall following the letter
designating the tire speed rating 0087
( Y page 140).
No specification given: absence of any text
(like in above example) indicates a
standard load (SL) tire.
XL or 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
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” 0047, “Tire size” 008A,
“Tire type code” 0088, and “Date of
manufacture” 0086.
i For illustration purposes only. Actual
data on tires are specific to each vehicle
and may vary from data shown in above
illustration.
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DOT (Department of Transportation)
Tire branding symbol 0046 which denotes the
tire meets requirements of the U.S.
Department of Transportation.
Manufacturer’s identification mark
Manufacturer’s identification mark 0047
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 ( Y page 126).
Tire size
Code 008A indicates the tire size.
Tire type code
Tire type code 0088 may, at the option of the
manufacturer, be used as a descriptive
code for identifying significant
characteristics of the tire.
Date of manufacture
Date of manufacture 0086 identifies the week
and year of manufacture.
The first two figures identify the week,
starting 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.
Tire ply material
i For illustration purposes only. Actual
data on tires are specific to each vehicle
and may vary from data shown in above
illustration.
This marking tells you about the type of
cord and number of plies in the
sidewall 0046 and under the tread 0047.
Tire and loading terminology
Accessory weight
The combined weight (in excess of those
standard items which may be replaced) of
automatic transmission, power steering,
power brakes, power windows, power seats,
radio, and heater, to the extent that these
items are available as factory-installed
equipment (whether installed or not).
Air pressure
The amount of air inside the tire pressing
outward on each square inch of the tire. Air
pressure is expressed in pounds per square
inch (psi), or kilopascal (kPa) or bars.
Aspect ratio
Dimensional relationship between tire
section height and section width expressed
in percentage.
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Bar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi) to
1 bar; there are 100 kilopascals (kPa) to
1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least 3 hours or
driven no more than 1 mile (1.6 km).
Curb weight
The weight of a motor vehicle with standard
equipment including the maximum
capacity of fuel, oil, and coolant, and, if
so equipped, air conditioning and
additional optional equipment, but
without passengers and cargo.
DOT (Department of Transportation)
A tire branding symbol which denotes the
tire meets requirements of the U.S.
Department of Transportation.
GAWR (Gross Axle Weight Rating)
The GAWR is the maximum permissible axle
weight. The gross vehicle weight on each
axle must never exceed the GAWR for the
front and rear axle indicated on the
certification label located on the driver’s
door B‑pillar.
GVW (Gross Vehicle Weight)
The GVW comprises the weight of the
vehicle including fuel, tools, installed
accessories, passengers and cargo. The
GVW must never exceed the GVWR indicated
on the certification label located on the
driver’s door B‑pillar.
GVWR (Gross Vehicle Weight Rating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight
of the vehicle including all options,
passengers, fuel, and cargo. It is indicated
on certification label located on the
driver’s door B‑pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are
100 kilopascals (kPa) to 1 bar.
Maximum load rating
The maximum load in kilograms and pounds
that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
total load limit and production options
weight.
Maximum permissible tire inflation
pressure
This number is the greatest amount of air
pressure that should ever be put in the tire.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lbs).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.
Production options weight
The combined weight of those installed
regular production options weighing over
5 lbs (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
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accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.
PSI (Pounds per square inch)
A standard unit of measure for air
pressure.
Recommended tire inflation pressure
The recommended tire inflation pressure
for normal driving conditions is listed on
the Tire and Loading Information placard
located on driver’s door B‑pillar and
provides best handling, tread life and
riding comfort.
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated.
Sidewall
The portion of a tire between the tread and
the bead.
TIN (Tire Identification Number)
Unique identifier which facilitates
efforts by tire manufacturers 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”.
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
manufacturers 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.
Total load limit
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle’s
designated seating capacity.
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 U.S. government
testing procedures. The ratings are molded
into the sidewall of the tire.
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