2003 BMW 320i SEDAN tires

114Special operating instructions
Break-in proceduresTo ensure that your vehicle continues to
provide maximum economy throughout
an extended service life, we request
that you devote careful attention to the
following instructions.Engine and differentialThe first 1,250 miles/2,000 km:
Attempt to constantly vary both vehicle
and engine speeds during these initial
miles while remembering to avoid
engine speeds in excess of 4,500 rpm
and/or vehicle speeds of over
100 mph / 160 km/h:
Always obey all official speed limits.
Refrain from using full throttle and avoid
pressing the accelerator beyond the
kickdown point.
You can then proceed to increase both
engine and vehicle speeds once the ini-
tial 1,250 miles/2,000 km have elapsed.
Please remember to observe these
same break-in procedures if either the
engine or the differential should have to
be replaced later in the course of the
vehicle's service life.
TiresOwing to technical factors associated
with their manufacture, tires do not
achieve their full traction potential until
an initial break-in period has elapsed.
We thus ask you to drive with extra care
during the first 200 miles/300 km.
Always obey all official speed limits.
When the vehicle is operated on
wet or slushy roads, a wedge of
water may form between the tire and
the road surface. This phenomenon is
referred to as hydroplaning and can
lead to partial or complete loss of trac-
tion, vehicle control and braking effec-
tiveness. Reduce your speed on wet
roads. before the brake pads and rotors
achieve the optimal pad-surface and
wear patterns required for trouble-free
operation and an extended service life
later on.
To break in the separate parking brake
drums, apply the parking brake lightly
when coasting to a standstill – at a traf-
fic signal, for instance; use caution to
avoid posing a danger to other road
users.
You can prevent corrosion in the drums
by periodically repeating this proce-
dure.
The brake lamps do not come on
when the parking brake is set.
Vacuum for the brake system servo unit
on your BMW is available only when the
engine is running. When you move the
vehicle with the engine off – when tow-
ing, for example – substantially higher
levels of pedal force will be required to
brake the vehicle. before the clutch starts to operate at
optimum efficiency. Remember to
engage the clutch carefully during this
initial period.

115
Driving notes
Brakes: do not drive with your foot
resting on the brake pedal. Even
light but consistent pedal pressure can
lead to high temperatures, brake wear
and possibly even brake failure.
Hydroplaning: when driving on wet or
slushy roads, reduce vehicle speed. If
you do not, a wedge of water may form
between the tires and the road surface.
This phenomenon can lead to partial or
complete loss of contact between the
tires and road surface, as well as loss of
vehicle control and braking ability.
Driving through water: do not drive
through water on the road if it is deeper
than 1 ft/30 cm, and then only at walk-
ing speed. Otherwise, the vehicle's
engine, the electrical systems and the
transmission may be damaged.
Rear tray: never use it to store heavy or
hard objects, as otherwise occupants
could be injured during braking maneu-
vers.
Clothes hooks: when hanging clothing
from the hooks, be sure that they will
not obstruct the driver's vision. Do not
hang heavy objects on the hooks. If you
do so, they could cause personal injury
during braking or evasive maneuvers.<
Antilock Brake System (ABS)The conceptABS keeps the wheels from locking
during braking, thereby enhancing
active driving safety.Braking with ABSIf you are in a situation that requires full
braking, you will exploit the full benefits
of the ABS system if you apply maxi-
mum pedal pressure – panic stop.
Since the vehicle maintains steering
responsiveness, you can avoid possible
obstacles with a minimum of steering
effort, despite the full brake application.
Pulsation at the brake pedal combined
with sounds from the hydraulic circuits
indicates to the driver that ABS is in its
active mode.Dynamic Brake Control (DBC)DBC is included in the DSC, refer to
page 80.
The system responds to sudden, high-
intensity applications of force to the
brake pedal by automatically braking
the vehicle with maximum boost to
achieve the shortest possible braking
distances during "panic stops". This
system exploits all the benefits of ABS.Do not reduce the pressure exerted
against the brake pedal until the brak-
ing maneuver has been completed.
DBC is deactivated when you release
the brake pedal.
Cornering Brake Control (CBC)CBC is an advanced engineering devel-
opment of ABS. When braking during
cornering with high lateral accelera-
tion, or when braking during a lane
change, vehicle stability is improved
and the steering response is enhanced.
OverviewControlsMaintenanceRepairsDataIndex

117 Wheels and tires
Tire inflation pressureInformation for your safetyThe factory-approved tires are matched
to your vehicle and have been selected
to provide optimum safety and driving
comfort when used properly.
It is not merely the tire's service life, but
also driving comfort and – above all else
– driving safety that depend on the con-
dition of the tires and the maintenance
of the specified tire inflation pressure.
Incorrect tire inflation pressure is a fre-
quent cause of tire damage. Tire pres-
sure also has a major effect on your
BMW's handling response.
Be sure to check the tire inflation
pressure, including the pressure
of the space-saver spare tire or the
spare tire, on a regular basis, at least
twice a month and before every
extended journey, refer to page 25.
Otherwise, incorrect tire pressure can
lead to poor handling, to tire damage
and accidents.<
Tire conditionTire tread – tire damageInspect your tires frequently for tread
wear, signs of damage and for foreign
objects lodged in the tread. Check the
tread depth.
Tread depth should not be allowed to
go below 1/8 in / 3 mm, even though
the legally specified minimum tread
depth is 1/16 in / 1.6 mm.
Below 1/8 in / 3 mm tread depth, there
is a great risk of hydroplaning, even at
relatively moderate speeds and with
only small amounts of water on the
road. Tread wear indicators in the
tread-groove base – see arrow – are
distributed around the wheel circumfer-
ence and are labeled on the tire side-
wall with TWI – Tread Wear Indicator. At
a tread depth of 1/16 in / 1.6 mm, the
indicators signal that the legally permis-
sible wear limit has been reached.
Do not drive on a deflated – flat –
tire. A flat tire greatly impairs
steering and braking response, and can
lead to complete loss of control over
the vehicle. Avoid overloading the vehi-
cle so that the permitted load on the
tires is not exceeded. Overloading can
lead to overheating and internal tire
damage.
The ultimate result can assume the
form of a sudden air loss.
Unusual vibrations encountered during
normal vehicle operation can indicate a
flat tire or some other vehicle malfunc-
tion. This type of problem can be
caused by contact with curbs, etc. This
is also true for irregularities in the vehi-
cle's handling characteristics, such as a
pronounced tendency to pull to the left
or right. Should this occur, respond by
immediately reducing your speed. Pro-
OverviewControlsMaintenanceRepairsDataIndex

118
ceed carefully to the nearest BMW cen-
ter or professional tire center, or have
the vehicle towed in to have it, its
wheels or its tires inspected.
Tire damage up to and including sud-
den and complete air loss can endan-
ger the lives of both the vehicle occu-
pants and other road users.<
Tire replacementTo maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer.DOT quality gradesTread wear
Traction AA A B C
Temperature A B C
All passenger car tires must con-
form to Federal Safety Require-
ments in addition to these grades. rating based on the wear rate of the tire
when tested under controlled condi-
tions 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 condi-
tions of their use, however, and may
depart significantly from the norm due
to variations in driving habits, service
practices and differences in road char-
acteristics and climate.
TractionThe 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 speci-
fied government test surfaces of
asphalt and concrete. A tire marked C
may have poor traction.
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 charac-
teristics. highest – B, and C, representing the
tire's resistance to the generation of
heat and its ability to dissipate heat
when tested under controlled condi-
tions 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 tem-
perature can lead to sudden tire failure.
The grade C corresponds to a level of
performance which all passenger car
Tire condition

119
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.
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 heat buildup
and possible tire failure. applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Tread wear 200
Traction AA
Temperature A
BMW advises against using
retreaded tires, since driving
safety may be impaired. This is due to
the possible variations in casing struc-
tures and, in some cases, to their
extreme age, which can lead to a
decrease in their durability.<
Tire ageThe date on which the tire was manu-
factured is indicated by the code on the
sidewall:
DOT... 3502 indicates that the tire was
manufactured in week 35 of the year
2002.
BMW recommends the replacement of
all tires – including the spare tire* –
when the tires are no more than 6 years
old, even if a tire life of 10 years is pos-
sible.Run Flat tires*Run Flat tires consist of self-supporting
tires and special rims. The tire rein-
forcement ensures that the tire retains
some residual safety in the event of
pressure drop and driving remains pos-
sible to a restricted degree. The vehicle
is equipped with a Tire Pressure Moni-
tor (TPM) or Flat Tire Monitor, which
indicate a flat tire.
For additional information on the Tire
Pressure Monitor (TPM) or Flat Tire
Monitor, refer to page 85 or 86.
Run Flat tires are only possible in
conjunction with the Tire Pres-
sure Monitor (TPM) or Flat Tire Moni-
tor.<
Tire replacement
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120
Wheel and tire combinationsThe right choice
BMW recommends using only
wheels and tires that have been
approved by BMW for use on your par-
ticular model. Although other wheels
and tires may theoretically have the
same dimensions, variations in factors
such as manufacturing tolerances can
result in contact between tire and body-
work, ultimately leading to serious acci-
dents. BMW cannot evaluate all tires
and wheels on the market, and is thus
unable to guarantee that the vehicle will
continue to perform safely if unap-
proved tires and/or wheels are
mounted.<
For each tire size, BMW has assessed
the safe performance of specific tire
brands and approved them for use.
Consult any BMW center for details.
Comply with any local/national regula-
tions, for example by recording the tire
type in the vehicle documents.
The correct wheel-tire combina-
tion affects various systems such
as ABS, ASC+T/DSC and ADB/
ADB-X/DBC. The function of these sys-
tems is impaired if improper wheel-tire
combinations are used.
For this reason, use only tires of the
same manufacture and tread configura-
tion. In the event of a flat tire, for exam-
ple, remount the approved wheel and
tire combination as soon as possible.<
StorageStore tires in a cool, dry place, protect-
ing them against light whenever possi-
ble. Protect the tires against contact
with oil, grease and fuel.
Winter tiresChoosing the right tireBMW recommends winter tires – M+S
tires – for operation under inclement
winter driving conditions. While all-sea-
son tires – M+S designation – provide
better winter traction than the corre-
sponding summer tires, they generally
do not achieve the performance of win-
ter tires.
In the interest of safe tracking and
steering response, install winter tires
made by the same manufacturer and
having the same tread configuration on
all four wheels.
Never exceed the maximum
speed for which the winter tires
are rated.
Unprofessional attempts by laymen to
service tires can lead to damage and
accidents.
Have this work performed by trained
professionals only. Any BMW center
has the required technical knowledge
and the proper equipment and will be
happy to assist you.<

121
Tire condition, tire pressureAt tread depths below approx. 3/16 in /
4 mm, winter tires display a perceptible
decrease in their ability to cope with
winter driving conditions, and should be
replaced in the interest of safety.
Comply with the specified tire inflation
pressures — and be sure to have the
wheel and tire assembly balanced
every time you change a tire or wheel.Snow chains*Only certain snow chains have been
tested by BMW and determined and
approved as roadworthy. Consult any
BMW center for details. BMW recom-
mends using only these approved fine-
link snow chains. Use them in pairs on
either summer or winter tires, but only
on both rear wheels.
BMW 325xi, 330xi: only in an emer-
gency – for instance, with the vehicle
stuck on one side, or when obstruc-
tions make it impossible to reach one
tire – a chain may also be mounted on
just one tire for the limited period
needed to resolve the problem.
Comply with all manufacturer's safety
precautions when mounting the chains.
Do not exceed a speed of 30 mph /
50 km/h when using snow chains.You cannot mount snow chains on the
following tires:
225/50 R 16
225/45 R 17
225/40 R 18
245/40 R 17
255/35 R 18Winter tires
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144
13. Wheels with full wheel covers*:
place the wheel cover with the
valve opening – see arrow – over
the valve. Use both hands to press
the cover securely onto the rim
14. Check and correct the tire inflation
pressure at the earliest opportunity.
Vehicles with Tire Pressure Monitor
(TPM)/Flat Tire Monitor: after
mounting the spare tire or correct-
ing the tire inflation pressure, reini-
tialize the system, refer to pages 85
and 86.
Protect valve stems and valves from dirt
using screw-on valve stem caps. Dirty
valve stems frequently lead to slow
pressure loss.
Do not attempt to install the full
wheel cover on the space-saver
spare tire, since this could damage the
cover.<
The vehicle jack is designed for
changing wheels only. Do not
attempt to raise another vehicle model
with it or to raise any other type of load.
To do so could cause accidents and
personal injury.
To ensure continued safety, have the
tightness of the torque bolts checked
with a calibrated lug wrench – torque
specification: 88.5 lb ft/120 Nm – at the
earliest opportunity.<
When storing a wheel in the spare tire
recess, take care to avoid bending the
threaded rod.
If light-alloy wheels other than original
BMW light-alloy wheels have been
mounted, it may be necessary to use
different lug bolts for those wheels.
Replace the defective tire as soon as
possible and have the new wheel/tire
balanced.
Driving with the space-saver
spare tireDrive cautiously. Do not exceed a
speed of 50 mph / 80 km/h.
Be aware that vehicle handling may be
altered. Anticipate, e.g., reduced track-
ing during braking, longer braking dis-
tances, and changed steering charac-
teristics when approaching limit
conditions. These handling characteris-
tics will be even more pronounced if
winter tires are mounted.
Only one space-saver spare tire
may be mounted at one time.
Mount a wheel and tire of the original
size at the earliest possible opportu-
nity. For certain wheel/tire combina-
tions, the size of the spare tire will
differ from that of the remaining tires.
The spare tire is fully functional at all
loads and speeds. However, the spare
tire should be replaced at the earliest
possible opportunity in order to achieve
the original operating conditions.<
Changing a wheel