Abstract: According to the invention, a transducer is mounted fixed in the area of the hub of the wheel in question, which transducer continuously is affected by the changes in the dynamic behavior of the tire which occurs at driving owing to dropping air pressure. The output signal from the transducer is processed in an electronic unit for forming a secondary signal, which is an expression for the vertical acceleration component in the output signal. When the secondary signal deviates by an amount critical for the driving safety from a nominal value, warning is released.

Abstract: A device for eliminating the locking risk of vehicle wheels at the application of a braking force, comprises an accelerometer mounted on a non-rotary portion connected with the wheel axle for emitting continuously, in response to the motions of the mounting point due to irregularities of the road, a primary signal indicative of the acceleration of the point as influenced by the damping properties of the wheel tire; an electronic unit for transforming the primary signal to a secondary signal, the strength of which is related to the speed of changes in the primary signal, and a control device connected to the electronic unit and controlling the braking force of a fluid-operated brake system so as to momentarily reduce the braking force in response to a sudden change in the secondary signal, corresponding to a sudden reduction in the ground braking moment of the wheel and due to reduced damping of the tire, whereby the locking risk is removed.

Abstract: According to the invention, an accelerometer (G) is attached on the spring suspension (U) of the wheel (H) in question and capable upon passing of the vehicle over road irregularities to emit a decaying A.C. signal (S) with information on the oscillations of the axle (A) and the damping of the tire. After integration in an integrator (I) the signal is a measure of the difference between the damping of the shock absorber at expansion and at compression. This signal is compared in a comparator (K) with a reference signal (V.sub.ref) for the permissible damping difference and results in alarm (L) upon achieving said difference.