A bicycle carrier for towing a second bicycle behind a first bicycle is provided. A carrier base has carrier wheels and is adapted to carry a wheel of the second bicycle. The carrier base is articulated to arms at their ends remote from the rear hub of the first bicycle. Clamping means are provided for clamping the wheel of the second bicycle in place on the base. The base can be carried above a rear wheel of the first bicycle when the carrier is not in use. A passenger carrier for a bicycle includes a carrier base having wheels, and handlebars on a member attached to the carrier base and foldable with respect thereto. Side sections of the base are locatable within a footprint of the central section when the carrier is not in use.

A kit for an electric cycle includes a powertrain module including a case, a battery disposed in the case, an electric motor in communication with the battery and disposed in the case, and a connecting port on the case. The kit includes a first module including a frame member configured to releasably engage the connecting port and a wheel rotatably connected to the frame member, a second module including a frame member configured to releasably engage the connecting port, and a releasable locking feature on the connecting port.