Operation, maintenance -> Tire condition for your BMW 3 Series 1997-2006
Wheels and tires
Tire inflation pressure
Tire condition
115
wall with TWI – Tread Wear Indicator. At
Information for your safety
a tread depth of 1/16 in / 1.6 mm, the
indicators signal that the legally permis-
sible wear limit has been reached.
The factory-approved tires are matched
to your vehicle and have been selected
to provide optimum safety and driving
comfort when used properly.
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.
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 pressure.
Avoid overloading the vehicle so that
the permitted load on the tires is not
exceeded. Overloading can lead to
overheating and internal tire damage.
You could have a blowout as a result.
Unusual vibrations encountered during
normal vehicle operation can indicate
tire failure or some other vehicle defect.
This type of problem can be caused by
contact with curbs, etc. This is also true
for irregularities in the vehicle's han-
dling characteristics, such as a pro-
nounced tendency to pull to the left or
right. Should this occur, respond by
immediately reducing your speed. Pro-
Incorrect tire inflation pressure is
a frequent cause of tire damage. It
also significantly influences the road-
holding ability of your BMW. Check tire
inflation pressures on a regular basis,
refer to page 25, at least every two
weeks and before beginning a longer
trip. Incorrect tire pressure can other-
wise lead to driving instability, tire dam-
age and accidents.<
Tire tread – tire damage
Inspect 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 only 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-
116 Tire condition
Tire replacement
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 blow-
outs, can endanger the lives of both the
vehicle occupants and other road
users<
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 performance.
DOT quality grades
>Treadwear
>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.<
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.<
Tread wear
The treadwear grade is a comparative
rating based on the wear rate of the tire
when tested under controlled condi-
tions on a specified government test
course.
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 condi-
tions on a specified indoor laboratory
test wheel.
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.
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
tires must meet under the Federal
Traction
The traction grades, from highest to
lowest, are AA, A, B and C.
Motor Vehicle Safety Standard No. 109.





