Tread depth is what clears water so your tires grip in the rain. As it wears down, wet stopping distance gets dangerously long. You can check it in seconds with a coin.
The coin test
Take a coin and insert it into the tread groove with the outer band or the top of the design pointing down into the tire. If that band or the head disappears into the groove, you have enough tread. If it stays fully visible, the tread is low and it is time to shop for tires.
Check several spots
Test the inner, middle and outer grooves across each tire, and check all four. Uneven readings across one tire point to a pressure or alignment problem that is wearing it unevenly.
Use the wear bars too
Every tire has small raised bars set into the grooves. When the tread wears down level with these bars, the tire is legally and practically worn out and needs replacing.
Frequently asked questions
What tread depth is too low?
Around 2 to 3 millimetres wet grip drops off sharply. Many drivers replace before the legal minimum for safety.
Do I need to replace all four tires?
Not always, but replace in pairs on the same axle so grip stays balanced, especially on the driven wheels.
When it is time, compare options in our tire guides.
