Division 3.2 Test procedure

To establish by test the damping ratio Dm, the damping ratio Dr, with hydraulic dampers removed, and the frequency F of the suspension, the loaded vehicle shall be either:

1. (a)

   driven at low speed (5 km/h ± 1 km/h) over an 80 mm step with the profile shown in Figure 1. The transient oscillation to be analysed for frequency and damping occurs after the wheels of the driving axle have left the step;

2. (b)

   pulled down by its chassis so that the driving axle load is 1,5 times its maximum static value. The vehicle held down is suddenly released and the subsequent oscillation analysed;

3. (c)

   pulled up by its chassis so that the sprung mass is lifted by 80 mm above the driving axle. The vehicle held up is suddenly dropped and the subsequent oscillation analysed;

4. (d)

   subjected to other procedures insofar as it has been proved by the manufacturer, to the satisfaction of the technical service, that they are equivalent.