Tread depth is an important tool to measure whether a tire is safe to drive on, but that doesn't explain the unusual ...

As tires lose tread depth, our testing shows that they’ll lose grip on wet surfaces and are more likely to hydroplane. The United States Tire Manufacturers Association agrees: “Tread equals ...

But some manufacturers add some sort of marker (like an embossed Michelin ... New tires usually have 9/32nds to 11/32nds of ...