how much tire tread
The Penny Test. In the United States, tire tread depth is measured in 32nds of an inch. New tires typically come with 10/32â or 11/32â tread depths, and some truck, SUV and winter tires may have deeper tread depths than other models. The U.S. Department of Transportation recommends replacing tires when they reach 2/32â, and many states legally require tires to be replaced at this depth.