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 InspectionThermostat Installation
Replace the O-rings [A] with new ones, and apply grease
to them.
Assemble:
O-rings
Thermostat Housing [B]
Thermostat [C]
Thermostat Cap [D]
Install the thermostat [A] in the housing so that the air
bleeder hole [B] is on top.
Tighten:
Torque - Thermostat Cap Bolts: 5.9 N ...
Coolant Deterioration Inspection
Remove the right lower fairing (see Lower Fairing Removal
in the Frame chapter).
Visually inspect the coolant in the reserve tank [A].
If whitish cotton-like wafts are observed, aluminum parts
in the cooling system are corroded. If the coolant is
brown, iron or steel parts are rusting. I ...
Balance Inspection
Remove the front and rear wheels (see Front/Rear Wheel
Removal).
Support the wheel so that it can be spun freely.
Spin the wheel lightly, and mark [A] the wheel at the top
when the wheel stops.
Repeat this procedure several times. If the wheel stops
of its own accord in various positi ...