A drive unit is situated between a first wheel axle and a second wheel axle and has an internal-combustion engine with a crankshaft system including a horizontally oriented crankshaft, which crankshaft acts upon a continuously variable transmission system which drives wheels of the first wheel axle and of the second wheel axle. The crankshaft is caused to rotate by at least one piston of the engine. The crankshaft interacts with a first set of V-pulleys of the transmission system, which first set of V-pulleys, by way of a first drive shaft, is connected with a first differential of the first wheel axle. The first set of V-pulleys, by way of an endless member, is in an operative connection with a set of V-pulleys which, with the interposition of a second drive shaft, influences a second differential of the second wheel axle.