tires SMART FORTWO COUPE 2008 Owner's Guide

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.

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 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
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 straight
ahead 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 build
up and
possible tire failure.

Tires and wheels
204
>> Operation Tire ply material
1
Plies in sidewall
2
Plies under tread
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 and under
the tread.
Tire and loading terminologyAccessory weight
The combined weight (in excess of those stan

dard items which may be replaced) of auto

matic 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 per

centage.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 equip

ment, but without passengers and cargo.

Tires and wheels
>> Operation
205
DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the tire
meets requirements of the U.S. Department of
Transportation
GAWR (G
ross A
xle W
eight R
ating)
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 (G
ross V
ehicle W
eight)
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 certifi

cation label located on the driver’s door
B
pillar.GVWR (G
ross V
ehicle W
eight R
ating)
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 regu

lar production options weighing over 5 lbs
(2.3 kilograms) in excess of those standard
items which they replace, not previously con

sidered in curb weight or accessory weight,
including heavy duty brakes, ride levelers,
roof rack, heavy duty battery, and special
trim.

Tires and wheels
206
>> Operation PSI (Pounds per s
quare i
nch)
A standard unit of measure for air pressure

> bar, kilopascal (kPa).
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 (T
ire I
dentification N
umber)
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 num

ber 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, poly

ester, 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
1/16in (1.6 mm) of tread remains.

Tires and wheels
>> Operation
207
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 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.
Rotating tiresThoroughly clean the mounting face of the
wheels and brake disks, i.e. the inner side of
the wheels/tires each time the wheels/tires
are changed. Check for and ensure proper
tire inflation pressure.For information on wheel change, see "Flat
tire" (

page 265).
G
Warning!
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.
G
Warning!
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.

Winter driving
208
>> Operation Before the onset of winter, have your vehicle
winterized at an authorized smart center. This
service includes:
>Check of anticorrosion and antifreeze
concentration.
• Addition of washer concentrate to the water
of the windshield/rear window.
Use a windshield washer concentrate la

beled for winter which is formulated for
temperatures below freezing point
(
page 308).
• Battery test. Battery capacity drops with
decreasing ambient temperature. A well
charged battery helps to make sure that the
engine can be started, even at low ambient
temperatures.
• Tire change.
Winter tiresAlways use winter tires at temperatures
below 45°F (7°C) and whenever wintry road
conditions prevail. Not all M+S rated tires
provide special winter performance. Make
sure the tires you use show 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. Use of winter tires is the only way
to achieve the maximum effectiveness of the
ABS and ESP
® in winter operation.
For safe handling, make sure that all mounted
winter tires are of the same make and have the
same tread design.Always observe the speed rating of the winter
tires installed on your vehicle. If the maximum
speed for which your tires are rated is below
the speed rating of your vehicle, you must
place a notice to this effect where it will be
seen by the driver. Such notices are available
at your tire dealer or any authorized smart
center.
G
Warning!
Winter tires with a tread depth of less
than
1/6 in (4 mm) must be replaced. They
are no longer suitable for winter opera

tion.

Winter driving
>> Operation
209 Snow chains*
!
Remember that snow chains must always be
compatible with the tire sizes of a vehicle.
Snow chains that are approved by smart are
only permitted for the following tire size:
175/55 R15 on the rear axle.
For safety reasons, smart recommends that
you only use snow chains that have been
approved by smart.
Information on this is available from any smart
center.
Please refer to the separate operating
instructions for detailed information on
mounting the 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:
• Using snow chains is not permissible with all
wheel/tire combinations (

page 299).
• Use snow chains in pairs and on rear wheels
only. Follow the manufacturer's mounting
instructions.
!
If snow chains are mounted to the front
wheels, they may scrape against the body or
axle components. The tires or the vehicle
could be damaged as a result.
• Use of snow chains may be prohibited
depending on location. Always check local
and state laws before mounting snow
chains.
G
Warning!
When mounting or removing snow chains,
always park your vehicle on level ground,
set the parking brake and turn off the en

gine. The vehicle could otherwise move
and injure yourself or other road users.G
Warning!
When mounting and removing snow
chains, ensure that you and your vehicle
are at a safe distance from moving traf

fic. Not doing so could endanger other
road users or even lead to you being
injured by the vehicles behind you.

Driving instructions
>> Operation
215 Drive sensibly
save fuel
Fuel consumption, to a great extent, depends
on driving habits and operating conditions.
To save fuel you should:
• Shift gears in a timely manner.
• Avoid frequent acceleration and decelera

tion.
• Keep tires at the recommended inflation
pressures.
• Remove carriers* when not in use.
• Remove unnecessary loads.
• Allow engine to warm up under low load use.
• Have all maintenance work performed at the
intervals specified in the Maintenance
Booklet and as required by the Maintenance
System. Contact an authorized smart cen

ter.
Fuel consumption is also increased by driving
in cold weather, in stop
and
go traffic, on
short trips, and in hilly areas.
Catalytic converterYour smart is equipped with monolithic
type
catalytic converter, an important element in
conjunction with the oxygen sensors to
achieve substantial control of the pollutants
in the exhaust emissions. Keep your vehicle in
proper operating condition by following our
recommended maintenance instructions as
outlined in your Maintenance Booklet.
G
Warning
The catalytic converter can become very
hot. Coming into contact with the catalytic
converter could result in burns.
Note the following:
• Do not remove the protective heat
guards.
• Do not apply any underseal.
• As with any vehicle, do not idle, park, or
operate this vehicle in areas where
combustible materials such as grass,
hay, or leaves can come into contact
with the hot exhaust system, as these
materials could be ignited and cause a
vehicle fire.

Driving instructions
216
>> Operation
!
To prevent damage to the catalytic
converter, only use premium unleaded gaso

line in this vehicle.
Any noticeable irregularities in engine oper

ation should be repaired promptly. Otherwise,
excessive unburned fuel may reach the cata

lytic converter, causing it to overheat and
potentially start a fire.
It is essential to observe the following points,
as there is otherwise a danger of overheating
and the catalytic converter may be damaged.
• Fill up only with premium unleaded gasoline.
Even small quantities of leaded gasoline can
damage the catalytic converter.
• Make sure you adhere to the prescribed
service intervals.
• Never run the fuel tank empty.
• If the engine starts to misfire, bring the ve

hicle to an immediate standstill without en

dangering traffic.
• If the engine fails to start the first time, you
should not try to start it any more than
three times in succession.
• Do not try to start for more than four sec

onds at a time.
TiresTreadwear indicators (TWI) are required by
law. These indicators are located in six places
on the tread circumference and become visi

ble at a tread depth of approximately
1/16in
(1.6 mm), at which point the tire is considered
worn and should be replaced. The treadwear indicator appears as a solid
band across the tread.
Specified tire inflation pressures must be
maintained. This applies particularly if the
tires are subject to high loads (e.g. high
speeds, heavy loads, high ambient tempera

tures).
G
Warning!
If you feel a sudden significant vibration
or ride disturbance, or you suspect that
possible damage to your vehicle has
occurred, you should turn on the hazard
warning flashers, carefully slow down,
and drive with caution to an area which is
a safe distance from the road.
Inspect the tires and the vehicle under

body for possible damage. If the vehicle
or tires appear unsafe, have the vehicle
towed to the nearest smart center or tire
dealer for repairs.
G
Warning!
Although the applicable federal motor
vehicle safety laws consider a tire to be
worn when the treadwear indicators (TWI)
become visible at approximately
1/16in
(1.6 mm), we recommend that you do not
allow your tires to wear down to that
level. As tread depth approaches
1/8in
(3 mm), the adhesion properties on a wet
road are sharply reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction
varies widely.