2008 SMART FORTWO COUPE tire pressure

Tires and wheels
>> Operation
191 Checking tire inflation pressure
Regularly check your tire inflation pressure
at least once a month.
Check and adjust the tire inflation pressure
when the tires are cold. The tires can be con

sidered cold if the vehicle has been parked
for at least 3 hours or driven less than 1 mile
(1.6 km).
If you check the tire inflation pressure when
the tires are warm (the vehicle has been
driven for several miles or sitting less than
3 hours), the reading will be approximately
4 psi (0.3 bar) higher than the cold reading.
This is normal. Do not let air out to match the
specified cold tire inflation pressure. Other

wise, the tire will be underinflated.Checking tire inflation pressure manually
Follow the steps below to achieve correct tire
inflation pressure:
>Remove the cap from the valve on one tire.
>Firmly press a tire gauge onto the valve.
>Read tire inflation pressure on tire gauge
and check against the recommended tire
inflation pressure on the Tire and Loading
Information placard on the driver’s door
B
pillar (

page 185). If necessary, add air
to achieve the recommended tire inflation
pressure.
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If you have overfilled the tire, release tire
inflation pressure by pushing the metal stem
of the valve with e.g. a tip of a pen. Then
recheck the tire inflation pressure with the
tire gauge.
>Install the valve cap.
>Repeat this procedure for each tire.
G
Warning!
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.
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. Overload

ing the tires can overheat them, possibly
causing a blowout. Overloading the tires
can also result in handling or steering
problems, or brake failure.

Tires and wheels
192
>> Operation Checking tire inflation pressure electroni

cally with the Tire Pressure Monitoring
System (TPMS)
i
The
Tire
Pressure
Monitoring
System
(TPMS) is equipped with a combination low tire
pressure/TPMS malfunction telltale in the
instrument cluster (

page 34). Depending on
how the telltale illuminates, it indicates a low
tire pressure condition or a malfunction in the
TPMS system itself:
• If the telltale illuminates continuously,
one or more of your tires is significantly
underinflated. There is no malfunction in
the TPMS.
• If the telltale flashes for 60 seconds and
then stays illuminated, the TPMS system
itself is not operating properly.
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USA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the follow

ing two conditions:
(1) This device may not cause harmful inter

ference, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
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Canada only:
This device complies with RSS
210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference,
and
(2) this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.The TPMS only functions on wheels that are
equipped with the proper electronic sensors.
It monitors the tire inflation pressure in all
four tires. A warning is issued to alert you to
a decrease in pressure in one or more of the
tires.
G
Warning!
The Tire Pressure Monitoring System
(TPMS) does not indicate a warning for
wrongly selected inflation pressures.
Always adjust tire inflation pressure
according to the Tire and Loading Infor

mation placard on the driver’s door
B
pillar.
The TPMS is not able to issue a warning
due to a sudden dramatic loss of
pressure (e.g. tire blowout caused by a
foreign object). In this case bring the
vehicle to a halt by carefully applying the
brakes and avoiding abrupt steering
maneuvers.

Tires and wheels
>> Operation
193
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If a condition causing the TPMS to
malfunction develops, it may take up to
10 minutes for the system to signal a malfunc

tion using the TPMS telltale flashing and illu

mination sequence.
The telltale extinguishes after a few minutes
driving if the malfunction has been corrected.
G
Warning!
Each tire should be checked monthly
when cold and inflated to the inflation
pressure recommended by the vehicle
manufacturer on the Tire and Loading
Information placard. If your vehicle has
tires of a different size than the size in

dicated on the Tire and Loading Informa

tion placard, you should determine the
proper tire inflation pressure for those
tires.
As an added safety feature, your vehicle
has been equipped with a tire pressure
monitoring system (TPMS) that illumi

nates a low tire pressure telltale when
one or more of your tires is significantly
underinflated.
Accordingly, when the low tire pressure
telltale illuminates, you should stop and
check your tires as soon as possible, and
inflate them to the proper pressure.
Driving on a significantly underinflated
tire causes the tire to overheat and can
lead to tire failure.
Underinflation also reduces fuel effi

ciency and tire tread life, and may affect
the vehicle’s handling and stopping
ability. Please note that the TPMS is not a
substitute for proper tire maintenance,
and it is the driver’s responsibility to
maintain correct tire pressure, even if
underinflation has not reached the level
to trigger illumination of the TPMS low
tire pressure telltale.
Your vehicle has also been equipped with
a TPMS malfunction indicator to indicate
when the system is not operating
properly. The TPMS malfunction indicator
is combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately 1 minute and then remain
continuously illuminated.
This sequence will continue upon subse

quent vehicle start
ups as long as the
malfunction exists. When the malfunction
indicator is illuminated, the system may
not be able to detect or signal low tire
pressure as intended.
TPMS malfunctions may occur for a vari

ety of reasons, including the installation
of incompatible replacement or alternate
tires or wheels on the vehicle that pre

vent the TPMS from functioning properly.
Always check the TPMS malfunction tell

tale after replacing one or more tires or
wheels on your vehicle to ensure that the
replacement or alternate tires and
wheels allow the TPMS to continue to
function properly.

Tires and wheels
194
>> Operation
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Operating radio transmission equipment
(e.g. wireless headsets, two
way radios) in or
near the vehicle could cause the TPMS to mal

function.
Restarting the TPMSThe TPMS must be restarted when you have
adjusted the tire inflation pressure to a new
level (e.g. because of different load or driving
conditions). The TPMS is then recalibrated to
the current tire inflation pressures.
>Using the Tire and Loading Information
placard on the driver’s door B
pillar

(
page 185)
, make sure the tire inflation
pressure of all four tires is correct.
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Restart the TPMS after adjusting the tire
inflation pressure to the inflation pressure
recommended for the vehicle operating con

dition. Tire pressure should only be adjusted
on cold tires. Observe the recommended tire
inflation pressure on the Tire and Loading
Information placard on the driver’s door
B
pillar (

page 185).
1
Restarting TPMS button
G
Warning!
It is the driver’s responsibility to cali

brate the TPMS on the recommended cold
inflation pressure. Underinflated tires
affect the ability to steer or brake and
might cause you to lose control of the ve

hicle.

Tires and wheels
>> Operation
195
>Press Restarting TPMS button1.
>The combination low tire pressure/TPMS
malfunction telltale in the instrument
cluster (

page 34) flashes for approxi

mately 5 seconds and then goes out.
After driving a few minutes the system
verifies that the current tire inflation
pressures are within the system’s specified
range. Afterwards the current tire inflation
pressures are accepted as reference
pressures and then monitored.Potential problems associated with
underinflated and overinflated tires
Underinflated tires
Underinflated tires can:
• cause excessive and uneven tire wear
• adversely affect fuel economy
• lead to tire failure from being overheated
• adversely affect handling characteristicsOverinflated tires
Overinflated tires can:
• adversely affect handling characteristics
• cause uneven tire wear
• be more prone to damage from road
hazards
• adversely affect ride comfort
• increase stopping distance
G
Warning!
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.
G
Warning!
Follow recommended tire inflation
pressures.
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
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
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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
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For information purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.

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.

Tires and wheels
200
>> Operation Load identification
1
Load identification
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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
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For illustration purposes only. Actual data
on tires are specific to each vehicle and may
vary from data shown in above illustration.