Saturn 2009 ASTRA - Manual (Page 233)

If the vehicle has P205/55R16 size
tires, additional air pressure is
required when driving the vehicle at
speeds of 99 mph (158 km/h) or
higher. Set the cold tire inflation
pressure to the maximum inflation
pressure shown on the tire sidewall,
or 32 psi (220 kPa), whichever is
lower. See the example following.
Example:
The maximum load and inflation
pressure is molded on the tire’s
sidewall, in small letters, near the rim
flange. It reads something like this:
Maximum load 710 kg (1565 lbs)
350 kPa (51 psi) Max. Press.
For this example, the cold tire
inflation pressure for high-speed
driving should be set at 32 psi
(220 kPa).
When high-speed driving ends,
return the tire pressure to the
recommended cold inflation
pressure shown on the Tire and
Loading Information label.
See Loading the Vehicle on
page 8-30. Tire pressure should be
checked and correctly set when
the tires are cold. See Inflation - Tire
Pressure on page 9-47.
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your vehicle’s tires
and transmit tire pressure readings to
a receiver located in the vehicle.
Each tire, including the spare
(if provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on
the vehicle placard or tire inflation
pressure label. (If your vehicle
has tires of a different size than the
size indicated on the vehicle
placard or tire inflation pressure
label, you should determine the
proper tire inflation pressure
for those tires.)
As an added safety feature, your
vehicle has been equipped with
a tire pressure monitoring system
(TPMS) that illuminates a low
tire pressure telltale when one or
more of your tires is significantly
under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them to
the proper pressure. Driving on a
significantly under-inflated tire
causes the tire to overheat and can
lead to tire failure. Under-inflation
also reduces fuel efficiency and
tire tread life, and may affect the
vehicle’s handling and stopping
ability.
Please note that the TPMS is
not a substitute for proper tire
maintenance, and it is the driver’s
responsibility to maintain correct tire
pressure, even if under-inflation
has not reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Vehicle Service and Care 9-49