Porsche 911 2020 Owner's Manual page 311

e Only use snow chains approved by Porsche so
that sufficient clearance between the wheel well
and chain is assured.
e Remove ice and snow deposits in the wheel well
before installing the chains.
e Observe the different national regulations re-
garding maximum speeds.
Checking tire tread
e Check tire tread regularly, particularly before and
after long journeys.
e The original equipment tires on your Porsche
have built-in tire wear indicators. They are
molded into the bottom of the tread grooves and
will appear as approximately 1/2 in. (12 mm)
bands when the tire tread depth is down to 1/16
of an in (1.6 mm).
e When the indicators appear in two or more adja-
cent grooves, it is time to replace the tires. We
recommend, however, that you do not let the
tires wear down to this extent.
e Worn tires cannot grip the road surface properly
and are even less effective on wet roads.
e For safety reasons, replace the tires before the
wear indicators appear. Snow tires are no longer
suitable when their tread depth falls below 5/32
in. (4 mm).
e In the United States, state laws may govern the
minimum tread depth permissible. Follow all
such laws.
Measuring tire tread depth
e Insert a commercially available tread depth
gauge or caliper in the tire tread and measure the
tire tread depth.
Information
Unevenly worn tires indicate a fault in the vehicle:
e Visit an authorized Porsche dealer, as they have
trained technicians and the necessary parts and
tools.
Storing wheels
Do not use tires that are more than 6 years old.
Chemical additives, which make the tire rubber
elastic, lose their effectiveness over the course of
time and the rubber becomes brittle. The age of the
tire can be seen from the "DOT" code number shown
on the tire sidewall. If, for example, the last four
numbers are 3016, then the tire was produced in the
30th week of 2016.
e Always store wheels in a cool, dry and dark place.
Store tires without rims vertically.
e Do not store summer tires or park vehicles with
summer tires mounted at ambient temperatures
under 5 °F (-15 °C).
e Avoid contact with gas, oil or grease.
Balancing wheels
As a precaution, have wheels balanced in spring
(summer tires) and before winter (M+S tires) by an
authorized Porsche dealer.
e Visit an authorized Porsche dealer. Porsche rec-
ommends an authorized Porsche dealer, as they
have trained technicians and the necessary parts
and tools.
Changing a wheel
Working under the
WARNING
vehicle
The vehicle can slip off the jack.
e Make sure that there is no one inside the vehicle
when jacking it up and changing the wheel.
e Raise the vehicle only at the prescribed jacking
points on the vehicle underbody.
e Never jack up the vehicle on a surface that slopes
up, down or to the side.
e Only use the jack to raise the vehicle for chang-
ing a wheel.
e Always place the vehicle on solid supports when
working under the vehicle.
Information
The tools needed for changing wheels (jack, wheel
bolt wrench, mounting aids, etc.) are not included in
the standard scope of supply for the vehicle.
e For information on the tool required: Contact an
authorized Porsche dealer.
Information
The tire and wheel sizes on both axles are different.
When removing the wheels, mark the direction of
rotation and position on each wheel and carry out
the installation according to these markings.
e Only use wheels/tires with approved dimensions
for the relevant axle.
> Please refer to the vehicle registration docu-
ments or the "Technical data" section of this
manual.
Wheels and Tires
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
309