Subaru WRX & WRX STI Manuals 2015 WRX & WRX STI Owner's Manual | Page 443

11-30

Maintenance and service/Tires and wheels

Tires and wheels
& Types of tires
You should be familiar with type of tires
present on your vehicle.
! All season tires
All season tires are designed to provide
an adequate measure of traction, handling
and braking performance in year-round
driving including snowy and icy road
conditions. However all season tires do
not offer as much traction performance as
winter (snow) tires in heavy or loose snow
or on icy roads.
All season tires are identified by “ALL
SEASON” and/or “M+S” (Mud & Snow) on
the tire sidewall.
! Summer tires
Summer tires are high-speed capability
tires best suited for highway driving under
dry conditions.
Summer tires are inadequate for driving
on slippery roads such as on snowcovered or icy roads.
If you drive your vehicle on snow-covered
or icy roads, we strongly recommend the
use of winter (snow) tires.
When installing winter tires, be sure to
replace all four tires.

! Winter (snow) tires
Winter tires are best suited for driving on
snow-covered and icy roads. However
winter tires do not perform as well as
summer tires and all season tires on roads
other than snow-covered and icy roads.

& Tire pressure monitoring
system (TPMS) (if equipped)
The tire pressure monitoring system provides the driver with a warning message
by sending a signal from a sensor that is
installed in each wheel when tire pressure
is severely low. The tire pressure monitoring system will activate only when the
vehicle is driven. Also, this system may
not react immediately to a sudden drop in
tire pressure (for example, a blow-out
caused by running over a sharp object).
If you adjust the tire pressures in a warm
garage and will then drive the vehicle in
cold outside air, the resulting drop in tire
pressures may cause the low tire pressure
warning light to illuminate. To avoid this
problem when adjusting the tire pressures
in a warm garage, inflate the tires to
pressures higher than those shown on the
tire placard. Specifically, inflate them by an
extra 1 psi (6.9 kPa, 0.07 kgf/cm2) for
every difference of 108F (5.68C) between
the temperature in the garage and the

temperature outside. By way of example,
the following table shows the required tire
pressures that correspond to various outside temperatures when the temperature
in the garage is 608F (15.68C).
Example:
Tire size: 245/40R18 97W
Standard tire pressures:
Front: 33 psi (230 kPa, 2.3 kgf/cm2)
Rear: 32 psi (220 kPa, 2.2 kgf/cm2)
Garage temperature: 608F (15.68C)
Outside
temperature

Adjusted pressure
[psi (kPa, kgf/cm2)]
Front

Rear

308F (−18C)

36 (250, 2.5)

35 (240, 2.4)

108F (−128C)

38 (260, 2.6) 37 (255, 2.55)

−108F (−238C) 40 (275, 2.75) 39 (270, 2.7)

If the low tire pressure warning light
illuminates when you drive the vehicle in
cold outside air after adjusting the tire
pressures in a warm garage, re-adjust the
tire pressures using the method described
above. Then, increase the vehicle speed
to at least 20 mph (32 km/h) and check to
see that the low tire pressure warning light
turns off a few minutes later. If the low tire
pressure warning light does not turn off,
the tire pressure monitoring system may
not be functioning normally. In this event,