Honda Prelude 1990 Online Reference Owner's Manual page 107

NOTE:
Brake pads should be inspected for wear whenever the tires are
rotated.
Tire Traction
Worn tires or slippery road surfaces can reduce driving, cornering
and braking traction. To reduce the possibility of losing traction,
slow down when the road gets slippery, replace tires when wear
indicators are visible, and KEEP TIRES PROPERLY INFLATED.
Tire Replacement
The original tires on your car
have tread wear indicators to
indicate when they should be
replaced. The indicators appear
as bands about 12.7 mm (1/2 in)
wide when the tire tread depth
is less than 1.6 mm (1/16 in).
When indicators appear across
two or more grooves in a row,
you should replace the tire.
Driving on worn-out or under-inflated tires is very hazardous, and
will reduce braking effectiveness, steering accuracy and traction.
When replacing tires, use only the recommended tire size. Wheel
rim widths and offsets must be those recommended by American
Honda Motor Co., Inc. Contact the Zone Office nearest you as
shown on the inside of the back cover.
Tires and wheels other than those recommended may be unsafe.
Do not mix radial and bias ply tires on the same car.
INDICATOR
LOCATION
MARKS
TREAD WEAR
INDICATORS