an elongate frame such as for carrying vehicles includes length - adjusting and width - adjusting assemblies that enable the frame to fully occupy differently - sized enclosures . pivotably extensible and retractable length - adjusting sections form the length - adjusting assembly . several length settings are achievable by selectively unlocking different combinations of sections . overshooting of settings is avoided , despite machine - driven adjustment , by elimination of overtravel - type movement in each section . telescopically adjustable joints , each with automatic end position latching and backup stop protection , form the width - adjusting assembly and guide the frame &# 39 ; s sides in stable upright movement while the frame &# 39 ; s forward end is unfolded . minimal restrictions on vehicle size are achieved by a vehicle - supporting assembly including variable - tread wheel cradle supports , lengthwise - shifting posts which , together with the supports , establish length - adjustable vehicle - loading zones , an adapter assembly which operatively couples the width - adjusting assembly and each support to optimize tolerance for wider treads based on the width setting selected , and a toothed plate interface which operatively couples the length - adjusting assembly and each vertical post so that the frame &# 39 ; s lengthwise vehicle - carrying capacity is based on the length - setting selected .