Porsche 928 1982 Owner's Manual page 69

Tire replacement
In the interest of maximum safety and best all-
around car handling, always buy replacement
tires that have the same specifications with
regard to tire size, design, load carrying capa-
city, tread pattern, etc. This also applies to
Porsche-recommended alternate replacement
tires.
In case of tire damage where it is uncertain
whether there is a break in the ply with all its
consequences or tire damage caused by ther-
mal or mechanical overloading due to a loss
of pressure or any other prior damage, we
recommended that the tire be replaced for sa-
fety reasons.
If one faulty tire is replaced it should be noted
that the difference in tread depth on one axle
must not be more than 30 %.
Tire specifications are imprinted on the side-
wall of the tires. If in doubt, check with your
Porsche dealer.
When replacing tubeless tires, always in-
stall new valve stems. When replacing tires
requiring an inner tube, always install new
tubes.
New tires do not possess maximum traction,
They tend to be slippery. Break new tires in by
driving at moderate speed for the first 6 0 - 1 2 0
miles or 1 0 0 - 2 0 0 km.
Wheels
If you intend to use other than original equip-
ment wheels, be sure that they conform to
Porsche specifications for your model.
Check with your Porsche dealer regarding the
correct wheel specifications for type and mo-
del year.
Tire care
• Avoid damaging tires and wheels rims. If
you must drive over a curb or other obstacle,
drive slowly and at an angle. Frequently
check tires for uneven wear and damage.
• Remove imbedded material.
• Replace worn or damaged tires promptly.
• Replace missing valve dust caps.
• Keep oil and gasoline from tires.
• Keep tires inflated correctly.
Winter tires
For a better grip on snow and ice use radial
M + S tires or winter tires with studs. Check
with your local Motor Vehicle Bureau for
possible restrictions.
Winter tires should have the same load capa-
city as original equipment tires and should pre-
ferably be mounted on all four wheels. Winter
tires with studs should be run at moderate
speeds when new in order to give the studs
time to settle. Tires with badly worn treads and
studs are very dangerous. Make sure they
are replaced promptly.
Winter tires do not fulfill their purpose if the
tread depth is less than 5/32 in (4 mm).
Refer to "Hints for winter operation" for ad-
ditional details.
Removing and storing tires
The driving direction should be clearly marked
on all tires before removing them for storage.
This is to make sure that they are mounted
and run in the same direction as before. When
remounting, put tires with the most tread depth
at the front. Have tires/wheels balanced as
soon as possible.
Store tires in a cool and dry place.
New Tire Identifications
The European tire manufacturers have chang-
ed their tire identification system for SR and
HR-tires pertaining to maximum permissible
speed and maximum load carrying capacity
for belted tires. The following is an example
only.
During the transition period some tires might
show both old and new identification codes,
such as: 185/70 SR 15 M + S 88 Q. In this in-
stance, the new codes apply.
The identification codes for VR tires remain
unchanged; for example: 225/50 VR 16. (V=
maximum permissible speed for radial tires,
i. e. over 130 mph or 210 km/h).
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