The JOSKIN Hydro-Tandem and Hydro-Tridem running gears combine simplicity, reliability, high clearance and stability. The vehicle can indeed be easily pulled over any obstacle thanks to its semi-independent axle concept. The vehicle is pulled by leaves attached to an element under the chassis, which is itself located in front of each axle, thus offering a large clearance of up to 250 mm. The working principle of this suspension is based on the law of the communicating vessels. Only the hydraulic rams on the same side are connected to each other in a closed circuit. The independence of the circuits on both sides of the vehicle, combined with the fact that the oil is incompressible, ensures a perfect lateral stability. As a result, the vehicle is less likely to tilt in bends and on hills. Moreover, thanks to this design, the pressure transmitted to the ground is perfectly distributed between all the wheels, which also spares the soil structure.
The vehicles equipped with a Hydro-Tandem or Hydro-Tridem running gear can be delivered with an automatic height-adjustment: this system allows the suspension to be easily calibrated in "road" configuration after passing under a bridge, a tunnel, after maintenance work, etc., for which it is normally necessary to lower the suspension of the running gear to the stop.