A drive mechanism (101) for a portable electronic device (102), such as a mobile telephone or personal digital assistant, includes at least one wheel (113) engaging at least one track (103). In one embodiment, two tracks (103,104) are coupled to a first housing (105), while a pair of wheels (113,114) are coupled to a shaft (106) which is coupled to a second housing (107) by way of a shaft retaining member (111). The wheels (113,114), which may include wheel teeth (224,225) disposed about the perimeter (226,227) of the wheels that engage track teeth (112), pass along the tracks (103,104) to cause the first housing (105) to slide open or closed relative to the second housing (107). A preloaded tensioning device (108), which in one embodiment comprises to oppositely wound coiled springs disposed concentrically about the shaft (106) bias the first housing (105) and the second housing (107) towards an open position.