See also:

Center ventilators
Center ventilators Move the tab to adjust the flow direction. ...

Wear indicators
1) New tread 2) Worn tread 3) Tread wear indicator Each tire incorporates a tread wear indicator, which becomes visible when the depth of the tread grooves decreases to 0.063 in (1.6 mm). ...

Parking on a grade
Always block the wheels under both vehicle and trailer when parking. Apply the parking brake. You should not park on a hill or slope. But if parking on a hill or slope cannot be avoided, you shoul ...