Abstract: The tire crampon comprises a cross-shaped member having four arms, interconnected by half-braces bearing bushes for connection to a vehicle's wheel hub bolts. Counter-arms are slideable on the arms and each have a toothed sector rigidly associated with an end thereof. The counter-arms move radially outwardly away from the cross-shaped member upon having a centrifugal force applied thereto, and due to the biasing action of compression springs acting between the arms and the counter-arms, thereby causing the toothed sectors to grip the ground. Chains limit the excursion of the counter arms, which can also be locked in a retracted position by pawl devices.