A downhole tractor for operational use in well casing of a wellbore. The tractor comprising a tractor body, at least one actuator assembly, and at least one tractor wheel. The actuator assembly is actionable to shift the axis of rotation of the tractor wheel. The at least one tractor wheel includes at least one bifurcated tract having a leading and trailing edge for engaging the well casing. The at least one actuator assembly causes the at least one tractor wheel to switch from traversing a first vertical plane of the well casing to a second vertical plane of the well casing when actuated.