Pontiac Sunbird Owner's Manual page 226

lnflationlire Pressure
The Tire-Loading Information label
which is on the rear edge of the driver's
door shows the correct inflation
pressures for your tires, when they're
cold. "Cold" means your vehicle has
been sitting for at least three hours or
driven no more than a mile.
Don't let anyone t e l l you that
underinflation
or
overinflation is
all right. It's not. If your tires don't
have enough air (underinflation)
you can get:
4
Too
much flexing
Too
much heat
0
Tire overloading
Bad wear
4
Bad handling
4
Bad fuel economy.
If your tires have too much air
(overinflation), you can get:
4
Unusual wear
Bad handling
Rough ride
Needless damage from road
hazards.
When to Check:
Check your tires once a month or more.
Don't forget your compact spare tire. It
should be at 60 psi (420
kPa).
How to Check:
Use a good quality pocket-type gage to
check tire pressure. Simply looking at
the tires will not tell you the pressure,
especially if you have radial tires-
which may look properly inflated even if
they're underinflated.
If your tires have valve caps, be sure to
put them back on. They help prevent
leaks by keeping out dirt and moisture.
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