The groove where the wear indicator is located is 1/16 inch (1.6 mm) shallower than elsewhere on the tire. If the tread has worn so that the indicator is exposed, replace the tire.
Worn out tires have poor traction on wet roads.
Honda Civic Service Manual. Moonroof Wind Deflector Removal and Installation (4-door)
814160
Removal
1.
Moonroof Deflector
1.
Open the glass fully.
2.
Remove ...