Honda CBR 2018 Series Owner's Manual page 52

Maintenance Fundamentals
#
Inspecting Tread Depth
Inspect the tread wear indicators. If they
become visible, replace the tires immediately.
For safe riding, you should replace the tires
when the minimum tread depth is reached.
or TWI
Wear indicator
location mark
48
WARNING
3
Riding on tires that are excessively worn
or improperly inflated can cause a crash
in which you can be seriously hurt or
killed.
Follow all instructions in this owner's
manual regarding tire inflation and
maintenance.