Patent ID: 7204135

Claim:
A method of detecting at least one predetermined wear threshold on a tire tread pattern elements, comprising the steps of measuring an impedance value of a passive tuned circuit contained in at least one of the elements, and determining from the impedance value a discrete impedance variable representing wear of the at least one tread pattern element, wherein the method comprises providing a tuned circuit comprising a coil and a quantity n (n≧1) capacitors connected in parallel to the terminals of the coil, wherein the impedance variable is a function of one of the inductance of the coil or the capacitance of the quantity n capacitors, and wherein the inductance of the capacitance varies discretely when a wear threshold is reached, wherein a discrete increase in the inductance represents the tire reaching at least one wear threshold, wherein, the threshold is determined by measuring a discrete decrease in the resonant freguency, wherein the tread pattern elements each have a radially external surface for contact with the ground, and wherein the method comprises providing a coil with at least one short-circuit line, each line comprising a vertex contained inside a tread pattern element and directed towards the external surface of the tread pattern element, the vertices being situated at different heights in the radial direction of the tire, wherein the at least one wear threshold is reached when wear on the external face has broken the vertex of a respective short-circuit line.