How much tread is enough?
What 6/32 actually means, how to check it yourself, and when a tire is worn out.
How tread is measured
Tread depth is measured in 32nds of an inch, from the top of the tread down to the bottom of the groove. A tire with 7/32 has seven thirty-seconds of an inch of tread.
The numbers that matter
Most new passenger tires start around 10/32 to 11/32. Truck and all-terrain tires often start deeper.
In most states, 2/32 is the legal minimum. At that point the tire is worn out.
Many tire makers and safety groups suggest replacing tires at about 4/32 if you drive in rain a lot, because wet grip drops as tread gets shallow.
Check it with a coin
Put a penny into a groove with Lincoln's head pointing down. If you can see the top of his head, the tread is at or below 2/32.
Do the same with a quarter. If the tread touches Washington's head, you have at least 4/32.
How we show it
Every tire we list is measured with a gauge. The depth is in the listing title, and the tread photo shows the gauge sitting in the groove so you can read it yourself.