a portable , multi - platform friction drive system with a retractable motor drive assembly , containing all needed components of an electric friction drive system in a portable handheld case , including motor , batteries , and all associated electronics , as well as a mounting system that enables use on popular bike share bicycles , personal bicycles , and kick scooters . its mounting system enables the friction drive system to be easily installed in seconds on many varieties of bicycles or kick scooters , and to be removed just as easily when no longer needed . and by means of its retractable motor assembly , the present invention enables the friction drive system to be as compact , clean , and safe as possible so as to be easily carried and stored when not in use .