Porsche 911 Carrera Manual page 194

Snow tires
For a better grip on snow and ice, use radial M+S
tires with studs.
Check with your local Motor Vehicle Bureau for
possible restrictions.
Danger!
Risk of loss of control and damage to the
vehicle as well as serious personal injury or
death.
The standard tires profile and rubber mixture
are optimized for wet and dry driving condi-
tions, and may not prove favorable for snow
conditions.
f Therefore install M+S tires before driving in
such conditions.
Before mounting snow tires, consult with
your Porsche dealer. He has the technical
information necessary to advise you on
wheel and tire compatibility.
Snow tires should have the same load capacity as
original equipment tires and should be mounted on
all four wheels.
Snow tires with studs should be run at moderate
speeds when new in order to give the studs time
to settle.
194
Practical Tips, Emergency Service
Danger!
Tires with badly worn treads and studs are
very dangerous and could cause accidents
resulting in serious personal injuries or
death.
f Make sure they are replaced immediately.
Do not drive a vehicle equipped with snow tires at
prolonged high speed.
Snow tires do not have the same degree of trac-
tion on dry, wet or snowfree roads as a normal
tire.
Furthermore, snow tires wear rapidly under these
conditions.
Comply with all state and local laws
governing snow tire and tread depth
requirements.
Danger!
Risk of accident and serious personal injury
or death due to excessive speed.
f Always check the maximum speed rating on
the tire sidewall on any tire on the vehicle.
f Never exceed the maximum speed rating of
the tires.
Fit winter tires to both axles well before the cold
season begins.
Your authorized Porsche dealer will be pleased to
advise you.
Maintenance note
We recommend fitting winter tires on the vehicle at
temperatures below 45°F (7°C ).
Winter tires lose their traction capability when their
tread depth falls below 5/32 in. (4 mm).