Kia Optima: Inflation PressuresAll tire pressures (including the spare) should be checked monthly when the tires are cold. “Cold Tires” means the vehicle has not been driven for at least three hours or driven less than one mile (1.2 km). Recommended pressures must be maintained for optimum vehicle handling, and minimum tire wear.

All specifications (sizes and pressures) can be found on a label attached to the front driver side door.
The correct tire pressure is 30 psi (210 kPa). The compact spare should be maintained at 60 psi (420 kPa).
WARNING - Tire Inflation
Over inflation or under inflation can reduce tire life, adversely affect vehicle handling, and lead to sudden tire failure. You could lose control and have a serious accident. Follow all the guidelines about proper tire maintenance.
Tire Care
Tire RotationKey operations
Type A
Type B
Type A
Used to start the engine, lock and unlock the doors.
Type B
To remove the mechanical key, press and hold the release button and remove the
mechanical key.
To reinstall ...
Trunk Lid
To open the trunk, insert the key into the lock and turn it clockwise until
an audible “click” is heard.
To close the trunk, use both hands to push the trunk lid down until the
lock ...
Removal
Brake Booster
1.
Turn ignition switch OFF and
disconnect the negative (-) battery cable.
2.
Remove the air duct (B) and air
cleaner assembly (A).
...