In specialist literature it has been determined that the fuel consumption of cars travelling at high speed is less with four-wheel drive than with conventional drive via only one axle.The question is whether a previously unused potential saving also exists here for heavy commercial vehicles. By means of systematic consumption measurements under various operating conditions with precise monitoring of the parameters, the fuel consumption differentials of the axle arrangements 4 X 2, 4 X 4, and 6 X 4 are determined. Simultaneously, the effect on the speed/torque collective of the drive engine measured during these test runs is shown. The results show the same tendency both for the solo vehicle with a low slip load on the drive axle and for the tractor vehicle of a heavy long-distance tractor/trailer combination, while quantitative differences of course exist: the losses due to additional power transmission elements (transfer case) outweigh the gain as a result of the lower tractive load on the drive wheels.Furthermore, the test arrangement is described, with which the load collectives are measured and recorded in a form suitable for computer evaluation. Here great value has been placed on the possibility of using the method universally for different applications.