The average tread depth on new tires ranges from 10/32 of an inch to 11/32 of an inch. This guideline is not standardized among all tires and only serves as an estimation. Tires become dangerous when they reach tread depths of 2/32 of an inch or shallower.
Consumers can verify the depth of their tires' tread at various stages of use by employing a tire tread depth gauge. This is far more accurate than a ruler or tape measure. When a gauge is not available, many consumers turn a U.S. penny upside down and insert it between the tire's ribs. If most or all of Lincoln's head is not visible, the tire has sufficient treat remaining. This is because the distance from the edge of the penny to the top of Lincoln's head measures 2/32 inch.