the case in which a tire on the front axle is deflated and bearing on its safety insert said curve presents a strong spectral response between 50 and 75 hz with peaks linked to the different harmonics of the turn of the wheel in this case the 50 u2013 80 hz band b has been chosen as characteristic frequency band of that front axle the third curve illustrates the case in which one of the tires of the rear axle of the renault twingo is bearing on its safety insert two notable peaks are observed toward 20 and 40 hz the 20 u2013 50 hz band a is then chosen as characteristic band of the rear axle it is also observed in fig8 that in frequencies below 7 hz or between 100 and 200 hz there is practically no noticeable change in the curves whether or not running flat consequently in order to take into account the vibrational energy due to the type of road on which the vehicle runs the measurements are normed in the preceding characteristic frequency bands by measurement of the rms value in a band e such as 100 u2013 160 hz or 3 u2013 7 hz this makes it possible to rely on the quality of the bearing detection when the speed of the vehicle diminishes so that the first harmonic of the turn of the wheel becomes.