Abstract: A modulized bicycle frame includes at least two frame body members each sidelong symmetric to each other and having a head connecting portion, a seat connecting portion and a bottom-bracket connecting portion, and a plurality of fastening members for combining the frame body members to form the bicycle frame. The frame body members are easy to assemble and disassemble so as to facilitate replacement and modification of the modulized bicycle frame. Besides, the frame body members are suitable for mass manufacture, thereby saving manufacturing costs.

Abstract: A light-duty vehicle with an adjustable wheelbase includes a linkage assembly composed of at least one main rod, a movable support, at least one movable rod and at least one adjusting rod, at least one power source connected in the linkage assembly, a seat mounted on a connecting rod having one end pivotally connected to the movable rod, and a driving wheel set composed of at least one front wheel and at least one rear wheel. The rear wheel is rotatably connected to the adjusting rod, while an opposite end of the main rod is connected to a fixed rod, which is coupled to a front fork above the front wheel. Thereby, when the power source modifies the linkage assembly in posture, the wheelbase between the front wheel and the rear wheel is changed so that the seat is adjusted in posture and altitude.