Lexus GS300 1998 Owner's Manual page 332

40G002
To remove the spare tire:
1 Remove the spare tire cover.
2 Loosen the bolt and remove it.
When storing the spare tire, place it with the inner side of the
wheel facing up. Then bolt the tire in place and install the
spare tire cover to prevent the tire from flying forward during
a collision or sudden braking.
IN CASE OF AN EMERGENCY
319