Lexus GS430 User Manual page 589

The effectiveness of snow tires is lost if the tread
wears down below 4 mm (0.16 in.).
If you have tire damage such as cuts, splits, cracks
deep enough to expose the fabric, or bulges
indicating internal damage, the tire should be
replaced.
If a tire often goes flat or cannot be properly repaired due
to the size or location of a cut or other damage, it should
be replaced. If you are not sure, consult with your Lexus
dealer.
If air loss occurs while driving, do not continue driving.
Driving even a short distance can damage a tire beyond
repair.
Any tires which are over 6 years old must be
checked by a qualified technician even if damage is
not obvious.
Tires deteriorate with age even if they have never or
seldom been used.
This applies also to the spare tire and tires stored for
future use.
NOTICE
D When you purchase new tires, consult your
Lexus dealer. If you change from run−flat tires
to standard tires, a spare tire should also be
equipped.
D When the tires must be repaired or replaced,
have them repaired or replaced by your Lexus
dealer or an authorized tire dealer. The tire
pressure warning valves and transmitters will
be affected by the installation or removal of
tires.
D When the tires must be replaced, replace the
grommets for tire pressure warning valves and
transmitters as well.
CHASSIS
565