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 RotationInspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Measure the output voltage of the MAPS at idle and
IG ON.
Specification:
Refer to " ...
Tightening Torques
Item
kgf.m
N.m
lb-ft
Positive crankcase ventilation valve installation
0.19 ~ 0.29
1.9 ~ 2.8
1.4 ~ 2.1
...
Owner maintenance
The following lists are vehicle checks and
inspections that should be performed by
the owner or an authorized Kia dealer at
the frequencies indicated to help ensure
safe, dependable operation ...