Hydraulic drive makes 20-tonne truck lighter

, more than four times that of conventional tractors. The secret to the success is the Predator's two large rubberised tracks that spread the load over a large surface area and enable the vehicle to turn 360 degrees on the spot. The tracks are pushed forward by a pair of Brevini two-stage reduction drive systems, which provide the levels of torque required to power and position the machine that can weigh more than 43 tonnes when fully loaded. The truck's wheel drive units consist of hydraulic motors integrated with Brevini planetary gearboxes, making them small enough to fit inside the tracks themselves. The compact motors produce rotational speeds of up to 2750 rpm, which is geared down to a ratio of 40:1 by the Brevini gearboxes, providing levels of torque that can reach 38,000Nm. Despite the high gearing, the Predator is capable of reaching speeds of 13kmph unloaded and 8kmph at full carrying capacity. DP