Subaru 2002 Forester Owner's Manual page 352

Driving even a short distance warms up the tires and increases the tire
pressures. Also, the tire pressures are affected by the ambient tempera-
ture. It is best to check tire pressure outdoors before driving the vehicle.
When a tire becomes warm, the air inside it expands, causing the tire
pressure to increase. Be careful not to mistakenly release air from a
warm tire to reduce its pressure.
NOTE
D The air pressure in a tire increases by approximately 4.3 psi (30
2
kPa, 0.3 kg/cm ) when the tire becomes warm.
D The tires are considered cold when the vehicle has been parked
for at least three hours or has been driven less than one mile (1.6
km).
WARNING
Do not let air out of warm tires to adjust pressure. Doing so will
result in low tire pressure.
Incorrect tire pressures detract from controllability and ride comfort, and
they cause the tires to wear abnormally.
Maintenance and service
HS0251
– CONTINUED –
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