Abstract: A device for evaluating the deformation of vehicle tires running along the round comprises: means (10, . . . , 32, 34, 40, . . . ) for measuring the length (1.sub.1) of a first chord of said tires (1), said first chord extending along a first direction at a first distance from said ground; means (40) for calculating a theoretical length for a second chord of said tire located at a second distance from the ground as a function of the length of said first chord and of said first distance from the ground; means (10, . . . , 37, 40, . . . ) for measuring the length (1.sub.1) of said second chord of said tire (1) situated at said second distance from the ground; and means (40) for comparing the theoretical length of said second chord with the measured length of said second chord, and for generating an output signal representative of said comparison.