Abstract: With the bicycle in its normal standing position, the front fork (16) with its front wheel (6) is, by means of the handle bar assembly (700), turned 180.degree. to the rearward direction, and in this position it is blocked from turning, in that the handle bar elements (701, 702) are folded down, each against its respective upper frame member. The left crank arm subassembly (500) is removed. The rear wheel, after being loosened, is then slided forward on two guide tracks, and then tightened again. Thereafter, the front wheel (6) is removed. The front frame subassembly (300) and the rear frame triangle subassembly (200) are then turned into each other, about pivot bearing (203), whereby as the two subassemblies are turned, the two lower front frame member come between the two seat pillars and two rear fork members, and the rear wheel comes between the two lower front frame members, and then between the two upper front frame members, until the end position is reached. The total elapsed time is about 45 seconds.