Take The Penny Test
Insert a penny into your tire's tread groove with Lincoln's head upside down and facing you. If you can see all of the head, it's time to replace your tires.
Check The Tread Wear Indicator
You can also check the tread wear indicator. You can find the tread wear indicator less than an inch (2/32 of an inch) from the bottom of the tread groove. When the tread wears down to become even with this level, the tire should be replaced.
To avoid potential problems, have your tires checked at a Tire & Service Network location near you if you notice any of these common wear patterns:
WEAR ON BOTH EDGES: UNDERINFLATION
Underinflation increases the treadwear on a tire's outside edges and generates excessive heat, reducing the tire's toughness. Soft tires also increase rolling resistance, reducing fuel economy.
WEAR IN CENTER: OVERINFLATION
Overinflation increases wear on the center tread.
CUPS OR DIPS IN THE TREAD: WORN PARTS
Cupping or dipping is most common on front tires, but rear tires can cup as well.
SAWTOOTH EDGES: MISALIGNMENT
Misalignment causes erratic scrubbing against the road giving the tire's edges a sawtooth-like appearance.