What is "xtracycle"

For the defunct British auto maker see: Xtra (automobile) Xtracycle is the name of a company and the name commonly used for the variety of load-carrying bicycle, a longtail or a longbike, that results from use of the company's products: the FreeRadical kit, complete long-frame bicycles and associated accessories. Web forums and blogs often use the shorthand Xtrabike, Xtra, or simply X to refer to either the FreeRadical extension or the entire extended bicycle. An Xtracycle may be constructed by modifying an existing bicycle with a Free Radical extension, or by custom-building an extended-tail bicycle frame.