The rear end of a car cabin of the hard-top type is convertible into an open carrier section in that the side windows (6) are swung upwardly to a horizontal position and are displaced into a hollow roof section (8), which is releasably held between a front and a rear cabin frame section (14, 10), such that the roof section (8), when released, can be lowered into a platform carrier position on suitable support means. Thereafter the rear cabin frame section (10) with an associated rear door (2) is pushed forwardly so as to abut the front cabin frame section (14), whereby the rear end of the cabin is left as an open pick up section. For protecting the top side of the roof section (8) as now used as a load carrier a cover sheet (7) can be pulled over this top side, preferably from a sheet roll (23) arranged in a roller blind like manner along the lower edge of the rear door (2), inside the door structure.