The traction grades, from highest to low-
est, are AA, A, B, and C. Those grades rep-
resent 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 perform-
ance.
Temperature 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 pos-
sible 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 control-
led conditions on a specified indoor lab-
oratory test wheel. Sustained high temper-
ature 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 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 perform-
ance on the laboratory test wheel than the
minimum required by law. Rotating tires
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. 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. 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 speci-
fied for your vehicle’s rims.
For information on wheel change, see “Flat
tire” (Y page 187). 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: 0043
Uniform Quality Grading Standards
(Ypage 138)
0044 DOT, Tire Identification Number (TIN)
(Ypage 142)
0087 Maximum tire load (Y page 136)
0085 Maximum tire inflation pressure
(Ypage 133) Tires and wheels
139>> Operation. Z
tire failure may result and cause an acci-
dent 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. G
WARNING
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
a blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.
Tire load rating 0083is 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 1356 lbs
(615 kg) the tire is designed to support.
See also “Maximum tire load” (Y page 136)
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 142).
Tire speed rating G
WARNING
Even when permitted by law, never operate
a vehicle at speeds greater than the maxi-
mum speed rating of the tires.
Exceeding the maximum speed for which
tires are rated can lead to sudden tire fail-
ure, 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
0084indicates the
approved maximum speed for the tire.
Summer tires 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)
ZR...Y above 186 mph (300 km/h)
ZR...(Y) above 186 mph (300 km/h)
ZR above 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 0083and tire speed rating
0084.
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 capa-
bility.
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 capabil- Tires and wheels
141>> Operation. Z
The TIN is a unique identifier which facil-
itates efforts by tire manufactures to
notify purchasers in recall situations or
other safety matters concerning tires and
gives purchasers the means to easily iden-
tify such tires.
The TIN is comprised of “Manufacturer’s
identification mark” 0044, “Tire size”0087,
“Tire type code” 0085, and “Date of manufac-
ture” 0083.
i For illustration purposes only. Actual
data on tires are specific to each vehicle
and may vary from data shown in above
illustration.
DOT (Department of Transportation) Tire branding symbol
0043which denotes the
tire meets requirements of the U.S. Depart-
ment of Transportation.
Manufacturer’s identification mark Manufacturer’s identification mark
0044
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 (Y page 127).
Tire size Code
0087indicates the tire size. Tire type code Tire type code
0085may, at the option of the
manufacturer, be used as a descriptive
code for identifying significant charac-
teristics of the tire.
Date of manufacture Date of manufacture
0083identifies 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 side-
wall 0043and under the tread 0044. Tire and loading terminology
Accessory weight The combined weight (in excess of those
standard items which may be replaced) of
transmission, power steering, power
brakes, power windows, power seats, radio, Tires and wheels
143>> Operation. Z
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by 68 kilo-
grams (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
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 pres-
sure.
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 pro-
vides 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 “Man-
ufacturer’s identification mark”, “Tire
size”, “Tire type code” and “Date of manu-
facture”.
Tire load rating
Numerical code associated with the maxi-
mum 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 manu-
facturers also must indicate the ply mate-
rials 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 kilo-
grams (150 lbs) times the vehicle’s desig-
nated 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 con-
tact with the road. Tires and wheels
145>> Operation. Z
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:
R Using snow chains is not permissible
with all wheel/tire combinations
(Y page 216).
R Use snow chains in pairs and on rear
wheels only. Follow the manufacturer’s
mounting instructions.
R 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,
engage the parking brake, and switch off
the drive system. The vehicle could other-
wise 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 traffic. Not
doing so could endanger other road users or
even lead to you being injured by the vehi-
cles behind you. G
WARNING
The vehicle’s handling changes when driv-
ing with snow chains on any kind of road surface. This means that you should always
adapt your driving style to suit the current
road and weather conditions.
! If snow chains that do not meet require-
ments are mounted, they may scrape
against the body or axle components when
the vehicle is in motion. This could
result in damage to the rim/tire or vehi-
cle. Driving instructions
Drinking and driving
G
WARNING
Do not drink alcohol or take drugs and drive
or allow anyone to drive who has been
drinking alcohol or taking drugs. Even a
small amount of alcohol or drugs can affect
your reflexes, perceptions and judgment.
The possibility of a serious or even fatal
accident are greatly increased when you
drink or take drugs and drive. Pedals
G
WARNING
Make sure absolutely no objects are
obstructing the pedals’ range of motion.
Keep the driver’s footwell clear of all
obstacles. If there are any floormats* or
carpets in the footwell, make sure the ped-
als still have sufficient clearance.
During sudden acceleration or braking
maneuvers, the objects could get caught
between or beneath the pedals and restrict
your ability to brake or accelerate. This
could lead to accidents and/or injury. Power assistance
G
WARNING
With the drive system inactive, there is no
power assistance for the brake and steering Driving instructions
147>> Operation.
* optional Z
systems. In this case, it is important to
keep in mind that a considerably higher
degree of effort is necessary to brake and
steer the vehicle. Adapt your driving
accordingly. Brakes
G
WARNING
Make sure not to endanger any other road
users when carrying out braking maneu-
vers.
Refer to the description of the hydraulic
brake assistant (Y page 48).
! Because the ESP ®
operates automati-
cally, the ignition must be switched off
when the parking brake is being tested
on a brake test dynamometer. Active
braking action through the ESP ®
may oth-
erwise seriously damage the brake sys-
tem 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 warn-
ing lamp in the instrument cluster comes
on (Y page 23) although the parking brake
is released.
Have the brake system inspected immedi-
ately. Contact an authorized electric drive
smart center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
electric drive smart center.
Only install brake pads and use brake fluid
recommended by smart. Inclines G
WARNING
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheat-
ing, thereby significantly reducing their
effectiveness and your ability to stop the
vehicle in sufficient time to avoid an acci-
dent.
Please observe the following guidelines to
avoid that the permitted maximum speed is
exceeded when driving on downhill grades:
R Do not move the gear selector lever to N.
R Recuperation is limited, if:
-the high-voltage battery is fully
charged or too cold
- the power electronics or the electric
motor is overheated.
When driving down long and steep grades,
do not depress the brake pedal perma-
nently. Depress it in intervals instead to
reduce the vehicle speed.
High and low stresses After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream will cool down
the brakes faster.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.
G
WARNING
Make sure not to endanger any other road
users when carrying out these braking
maneuvers. 148
Driving instructions>> Operation.
Wet road surface
G
WARNING
After driving in heavy rain for some time
without applying the brakes or through
water deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking
effect. Maintain a safe distance from vehi-
cles in front.
To help prevent brake disc corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes. G
WARNING
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.
Limited braking effect on salted roads Remember that the effect of the brakes can
be limited on salted road surfaces. A layer
of salt can form on brake discs and brake
pads, considerably reducing the friction
between the brake disc and the brake pad.
The effect is most noticeable after long
trips without braking, e.g. on the highway,
and after the vehicle has been parked for
several hours.
G
WARNING
The accumulation of salt on brake discs and
brake pads reduces braking effectiveness
and increases the distance necessary to
come to a complete standstill. This could
potentially cause an accident and/or per-
sonal injury.
To avoid this risk, you should
R brake carefully every now and then on
salted roads in order to remove any layer
of salt on the brake disc and brake pad, but do so without endangering any other
road users
R keep a good safe distance from the vehi-
cle in front and drive carefully
R press the brake carefully at the end of the
trip and again when beginning the next
trip in order to remove any salt residues
from the brake disc
New brake pads Only install brake pads recommended by
smart.
G
WARNING
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that
safe braking is substantially impaired.
This could result in an accident. G
WARNING
New brake pads will not achieve their opti-
mal braking effect until after several hun-
dred miles (kilometers). This means that
you must compensate for the reduced brak-
ing effect by pressing harder on the brake
pedal and adapt your driving style accord-
ingly. The same applies after brake pads or
brake discs have been changed. Drive sensibly - save energy
Energy consumption, to a great extent,
depends on driving habits and operating
conditions.
To save energy you should:
R Drive carefully and maintain a suitable
distance from the vehicle in front.
R Avoid frequent acceleration and decel-
eration.
R Keep tires at the recommended inflation
pressures.
R Remove carriers* when not in use. Driving instructions
149>> Operation.
* optional Z
R
Remove unnecessary loads.
R Have all maintenance work performed at
the intervals specified in the Mainte-
nance Booklet and as required by the
Maintenance System. Contact an author-
ized electric drive smart center.
Energy consumption is also increased by
driving in stop-and-go traffic, on short
trips, and in hilly areas. Tires
G
WARNING
If you feel a sudden significant vibration
or ride disturbance, or you suspect that
possible damage to your vehicle has occur-
red, you should turn on the hazard warning
flashers, carefully slow down, and drive
with caution to an area which is a safe dis-
tance from the road.
Inspect the tires and the vehicle underbody
for possible damage. If the vehicle or tires
appear unsafe, have the vehicle towed to the
nearest smart center or tire dealer for
repairs.
Treadwear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and
become visible at a tread depth of approx-
imately 1
/ 16 in (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. 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
/ 16 in
(1.6 mm), we recommend that you do not allow
your tires to wear down to that level. As
tread depth approaches 1
/ 8 in (3 mm), the
adhesion properties on a wet road are
sharply reduced. Depending upon the weather and/or road
surface (conditions), the tire traction var-
ies widely.
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
temperatures). 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 vehicle.
Continued driving with a flat tire or driv-
ing at high speed with a flat tire will cause
excessive heat build-up and possibly a
fire.
For more information, see “Tires and
wheels” (Y page 127). Hydroplaning
Depending 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 cautiously when it is raining. Tire traction
The 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. G
WARNING
If ice has formed on the road, tire traction
will be substantially reduced. Under such
weather conditions, drive, steer and brake
with extreme caution.
smart recommends winter tires
(Y page 146) with a minimum tread depth of 150
Driving instructions>> Operation.