A motor vehicle with an additional crawler undercarriage includes assemblies to reduce the load pressure transferred to the ground and to improve off-road performance. The assemblies include components used in conventional mass-produced vehicles, with a chassis (1. 1), a body with optional cargo area (1.2), undercarriage, such as axles (1.3) with steered (1.4) and/or unsteered wheels (1.5), tires (1.6), wheel suspension, spring support, steering and brakes, and an engine-transmission unit (1.7) with drive components. An additional crawler undercarriage (2) can be mounted and/or retrofitted on the chassis (1.1) between the axles (1.3) and used for traction in any terrain. The additional crawler undercarriage (2) includes an undercarriage (2.1) with drive wheels (2.2) and carrying wheels (2.3) and revolving crawler chains/crawlers (2.4) and associated elements, first means (3) for providing an optionally extendable and retractable connection of the undercarriage (2.1) with the chassis (1.1), and second means (4) for selectively transmitting or coupling a second drive from the motor vehicle to the additional crawler undercarriage (2), as well as third means (5) for controlling the operation of the additional crawler undercarriage (2), such as steering, braking, acceleration and speed of the crawler chains/crawlers (2.4).