2008 SMART FORTWO COUPE wheel

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
>> 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
212
>> Operation
BrakesRefer to the description of the hydraulic
brake assistant (

page 75).
!
Because the ESP
® operates automatically,
the engine must be shut off (key in starter
switch position0) when
• the parking brake is being tested on a
brake test dynamometer
• the vehicle is being towed with the front
axle raised
Active braking action through the
ESP
® may
otherwise seriously damage the brake system
which is not covered by the smart Limited
Warranty.Brake pad wear or a leak in the brake system
may be the reason for low brake fluid level in
the brake fluid reservoir.
The brake fluid level in the brake fluid
reservoir may be too low if the brake warning
lamp in the instrument cluster comes on
(

page 34) although the parking brake is
released.
Have the brake system inspected immediately.
Contact an authorized smart center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized smart
center.
Only install brake pads and use brake fluid
recommended by smart.Inclines
!
When driving down long and steep grades,
relieve the load on the brakes by shifting into
a lower gear to use the engine’s braking
power. This helps prevent overheating of the
brakes and reduces brake pad wear.
When using the engine’s braking power, a
drive wheel may not spin for an extended pe

riod of time, e.g. on slippery road surfaces.
This may cause serious damage to the drive

train which is not covered by the smart
Limited Warranty.
G
Warning!
Make sure not to endanger any other
road users when carrying out braking
maneuvers.

Driving instructions
>> Operation
217
For more information, see "Tires and wheels"
(
page 182).
HydroplaningDepending on the depth of the water layer on
the road, hydroplaning may occur resulting in
a loss of control, even at low speeds and with
new tires. Reduce vehicle speed, avoid track
grooves in the road and apply brakes cau

tiously when it is raining.
Tire tractionThe safe speed on a wet, snow covered or icy
road is always lower than on a dry road.
You should pay particular attention to the
condition of the road whenever the outside
temperatures are close to the freezing point.smart recommends winter tires
(
page 208)

with a minimum tread depth of approximately 1/6in (4 mm) on all four wheels for the winter
season to ensure normal balanced handling
characteristics. On packed snow, they can
reduce your stopping distance compared to
summer tires.
Stopping distance, however, is still consider

ably greater than when the road is not cov

ered with snow or ice. Exercise appropriate
caution.
!
Avoid spinning of a drive wheel for an ex

tended period when driving off on slippery
road surfaces. Otherwise, the the drivetrain
c o u l d b e d a m a g e d , w h i c h i s n o t co v e r e d b y t h e
smart Limited Warranty.
G
Warning!
Do not drive with a flat tire. A flat tire will
affect your ability to steer or brake and
may cause you to lose control of the vehi

cle. Continued driving with a flat tire or
driving at high speed with a flat tire will
cause excessive heat build
up and possi

bly a fire.
G
Warning!
If ice has formed on the road, tire trac

tion will be substantially reduced. Under
such weather conditions, drive, steer and
brake with extreme caution.

Driving instructions
218
>> Operation
Tire speed ratingRegardless of the tire speed rating, local
speed limits should be obeyed. Use prudent
driving speeds appropriate to prevailing
conditions.
An electronic speed limiter prevents your
vehicle from exceeding a speed of 90 mph
(145 km/h).The factory equipped tires on your vehicle
may have a tire speed rating above the maxi

mum speed permitted by the electronic speed
limiter.
Make sure your tires have the required tire
speed rating as specified for your vehicle in
t h e " T e c h n i c a l d a t a s e c t i o n " (

page 299), for
example when purchasing new tires.
For information on how to identify the tire
speed rating on a tire’s sidewall, see "Tire
size designation, load and speed rating"
(

page 196)
.
If you are uncertain about the correct read

ing of the information given on a tire’s side

wall, any authorized smart center will be glad
to assist you.i
For information on speed ratings for
winter tires, see "All
season and winter tires
"
(

page 199).
For additional general information on tire
speed markings on tire sidewall, see "Tire
speed rating" (

page 198).
Winter driving instructionsThe most important rule for slippery or icy
roads is to drive sensibly and to avoid abrupt
acceleration, braking and steering maneu

vers.
When the vehicle is in danger of skidding,
move gear selector lever to neutral
positionN. Try to keep the vehicle under
control by corrective steering action.
For information on driving with snow chains*,
see "Snow chains*" (

page 209).
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.
G
Warning!
On slippery road surfaces, never down

shift in order to obtain braking action.
This could result in drive wheel slip and
reduced vehicle control. Your vehicle’s
ABS will not prevent this type of loss of
control.