Acoustic medium of ultrasonic grip system consists of piezoelectric generator (1), wheel knuckle (9), ball bearing (10), wheel hub (11), wheel rim (15) and tyre of motor-car (20). The piezoelectric generator (1) creates ultrasound vibrations which are transferred through the acoustic medium to the surface of tyre (17). The ultrasound vibration on the surface of tyre (17) results in the separation of the surface of tyre (17) from the liquid (18) that may be found on tarmac (19) during the rain, which results in the fact that despite the unfavourable weather conditions the motor-car has an optimum rolling surface of tarmac. Also, the vibrations on the surface of tyre (17) in interaction with micro texture of tarmac increases the contact surface of tyre with tarmac, which results in the increase of coefficient of friction, higher grip of tyre and reduction of braking distance of motor-car. The ultrasonic grip system is activated at sudden braking, resp. activation of ABS system. Also, the system is activated on the occasion of activating the ESP and ASR system.