A small, typically gasoline-powered internal combustion engine mounted above the rear bicycle wheel propels the cycle forward by contacting the tire directly through a motorized roller. This simple design allows for relatively straightforward installation on most bicycles. An example would be a small two-stroke motor driving a rubber-coated wheel against the bicycle’s tire.
This method of propulsion offers a cost-effective and readily available means of motorized bicycle transportation. Its inherent simplicity allows for easier maintenance and repair compared to more complex integrated systems. Historically, these systems have provided accessible motorized transport in various parts of the world, particularly where affordability and ease of use are paramount. This accessibility has contributed to their continued popularity.