Tyre Pressures; Tyre Tread - BMW 840Ci Owner's Handbook Manual

Tyre pressures

Information for your safety
The factory-approved radial-ply
(braced tread) tyres have been chosen
to match your car's performance and
to ensure driving safety and the
desired standard of ride comfort.
The condition of the tyres and mainte-
nance of the specified tyre pressures
not only influence tyre life but also
road safety to a very considerable
extent.
Incorrect tyre pressures are often a
cause of tyre problems. They also have
a considerable effect on the roadhold-
ing of your BMW.
a
Check tyre pressures regularly
(including the spare wheel) before
starting a long journey and in any
event at least twice a month. Failing
this, incorrect tyre pressures could
render the car unstable when driven
or cause tyre damage which could
result in an accident.c

Tyre tread

Inspect tyres frequently for damage,
the presence of foreign bodies, unu-
sual wear and sufficient tread depth.
Tread depth should not be less than
3mm (app. 0.12 in), even if the mini-
mum legal requirement is only 1.6mm
(app. 0.06 in). You are recommended
to replace tyres when the tread depth
is down to 3 mm, or else the risk of
aquaplaning on even shallow water
will be increased.
We recommend fitting new tyres when
the treads are 3mm deep. If they
remain in use, wear indicators in the
base of the tread appear at a tread
depth of 1.6mm as a warning that the
legal wear limit (valid throughout
Europe since 01.01.1992) has been
reached.
When parking the car or driving over
loading ramps, workshop hoists etc.,
make sure that the side walls of the
tyres are not damaged by violent con-
tact with obstructions.
a
Never try to drive any further if a
tyre goes flat. If air pressure is lost
from a tyre, this seriously affects the
car's handling and braking, and could
cause the driver to lose control.
Avoid overloading the car, as this
could cause the tyres' load capacity
limit to be exceeded. Overheating can
also occur, and the tyre can suffer
internal damage at a relatively rapid
rate. This could lead to sudden pres-
sure loss.
Unusual vibration while the car is
being driven could indicate a tyre fault
or some other defect on your car. The
same applies to any other abnormal
road behaviour, such as pulling
severely to the right or left. In such
cases, reduce speed immediately.
Proceed carefully to the nearest BMW
Service station or tyre dealer, or have
the car towed there so that it can be
checked or its tyres inspected.
All forms of tyre damage (which could
in the worst case lead to sudden and
total loss of pressure) represent a risk
of serious or even fatal injury to the
car's occupants and to all other road
users.c
Online Edition for Part-No. 01 41 9 790 191 - © 12/98 BMW AG
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