Abstract: A system for determining tread wear of a tire includes a first wireless communication chip located at an inner surface of the tire and a second wireless communication chip located at an outer surface of the tire. The second chip resides in a slot extending through a housing located in a groove in a tread of the tire. The second chip moves in the slot toward the bottom of the groove in response to the tread wear. Methodology entails transmitting a first signal from a first chip, receiving the first signal at the second chip, transmitting a second signal from the second chip in response to receipt of the first signal, receiving the second signal at the first chip, computing a time delay between transmission of the first signal and receipt of the second signal, and determining tread wear of the tire in response to the time delay.