Abstract: A child's cycle is provided which is adaptable, as the child grows, between a tricycle configuration and a bicycle configuration, the cycle comprising a frame 4, 13, 14 with, in the bicycle configuration, a bicycle axle mounted on the frame and able to carry a rear wheel 8; and in the tricycle configuration, additionally a tricycle axle able to carry a second rear wheel, adapted to be coupled to the bicycle axle to form an axle 9 carrying two wheels, the axle being mounted on the frame. For this, one end of the bicycle axle is adapted for coupling it either to the frame or to the tricycle axle.