As the tire tread wears down, the tire becomes more susceptible to puncture and failure. An accepted estimate is that 90% of all tire failures occur during the last 10% of tread life (90% worn). So it is false economy and unsafe to use the tires until they are bald.
If any measurement is less than the service limit, replace the tire (see Tire Removal/Installation in the Wheels/Tires chapter).

Tread Depth Standard:
Front 3.6 mm (0.14 in.)
Rear 5.3 mm (0.21 in.)
Service Limit:
Front 1 mm (0.04 in.) (AT, CH, DE) 1.6 mm (0.06 in.)
Rear 2 mm (0.08 in.) (Up to 130 km/h (80 mph)) 3 mm (0.12 in.) (Over 130 km/h (80 mph))
| WARNING Some replacement tires may adversely affect handling and cause an accident resulting in serious injury or death. To ensure proper handling and stability, use only the recommended standard tires for replacement, inflated to the standard pressure. |
NOTE
Wheel/Tire Damage Inspection
Wheel Bearing Damage InspectionVehicle-down Sensor Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the vehicle-down sensor connector and connect
the measuring adapter [A] between these connectors
as shown in the figure.
Main Harness [B]
Vehicle-down Sensor [C]
Special Tool - Measuring Adapte ...
Battery Removal
Turn off the ignition switch.
Remove the front seat (see Front Seat Removal in the
Frame chapter).
Slide the red cap [A].
Disconnect the negative (–) cable [B] and then positive
(+) cable [C].
NOTICE
Be sure to disconnect the negative (–) cable first.
Remove the band [D] ...
Air Cleaner Housing Removal
Remove the fuel tank (see Fuel Tank Removal).
Disconnect the secondary fuel hose [A] from the delivery
pipe of the nozzle assy [B] (see Fuel Hose Replacement
in the Periodic Maintenance chapter).
Disconnect the secondary fuel injector connectors [C].
Free the lead from the grooves [D].
...