Lexus GS430 User Manual page 506

IN CASE OF AN EMERGENCY
G40024
To remove the spare tire:
Remove the luggage tray.
1
Loosen the bolt and remove it.
2
When storing the spare tire, place it with the outer side
of the wheel facing up. Then bolt the tire in place and
install the luggage tool box to prevent the tire from flying
forward during a collision or sudden braking.
482
G40007
4. Block the wheel diagonally opposite the flat tire to
keep the vehicle from rolling when it is jacked up.
When blocking the wheel, place a wheel block in front of
one of the front wheels or behind one of the rear wheels.