Buick 2005 Century Owner's Manual page 290

The compact spare is for temporary use only. Replace
the compact spare tire with a full-size tire as soon
as you can. See Compact Spare Tire on page 5-81.
See the storage instructions label to return the compact
spare to the trunk properly.
Be sure to calibrate low tire inflation system after you
replace the compact spare tire with a full-sized tire.
See Inflation - Tire Pressure on page 5-60.
5-80
A. Retainer
B. Cover
C. Compact Spare Tire
D. Nut
E. Jack
F. Wheel Wrench
G. Extension and Protector
H. Bolt Screw
I. Foam Holder