Torque is the central performance specification for construction equipment engines and hydraulic drives. It describes the force that a rotating system exerts on a shaft, measured in Newton-meters (Nm) or kilonewton-meters (kNm). For the equipment operator, high torque means: greater digging force, greater pulling force, greater compaction performance.
Diesel engines in construction machinery are optimized for high torque at low RPM (1,200–1,800 rpm) — unlike passenger car engines, which reach peak performance only at high RPM. A Liebherr R 926 tracked excavator, for example, delivers 680 Nm at 1,400 rpm. Electric construction equipment such as the Volvo EC230 Electric provide full torque from 0 rpm — a significant advantage for precision work.
In the hydraulic system, the torque of hydraulic motors determines the slew speed of the uppercarriage and the drive force of the tracks or wheels. The bucket breakout force is also specified as torque at the bucket pin and is a key criterion when selecting machinery for demolition and rock work.