Patent ID: 8065911

Claim:
A method for measuring characteristics of a tyre on a vehicle wheel, comprising: (a) moving the vehicle in a longitudinal direction so that the tyre passes over a laterally extending first measuring sensor comprising an array of individual force sensing elements which provide outputs related to contact pressure at points in a footprint of the tyre as the tyre passes over the first measuring sensor, the force sensing elements of the first measuring sensor being arranged laterally at positions across the width of the tyre as it passes over the first measuring sensor and being of sufficiently high resolution to detect positions within the tyre footprint where there is no contact between the tyre and the first measuring sensor as a result of there being a tread pattern in the surface of the tyre; (b) detecting the speed of the tyre in the longitudinal direction as it passes over the first measuring sensor; (c) sampling the outputs from the force sensing elements of the first measuring sensor at intervals as the tyre passes over, so as to provide pressure data representing the contact pressure at a number of points distributed laterally across and longitudinally along the tyre footprint that passes over the first measuring sensor; and (d) processing the pressure data representing the contact pressure and data representing the speed of the tyre in the longitudinal direction, to provide an indication representative of the extent of tread coverage over the tyre footprint that passes over the first measuring sensor.