If the misaligned shaft center lines are parallel but not coincident, then the misalignment is said to be parallel (or offset) misalignment. Or when the equipment shaft center lines are parallel, but are offset from each other, it is called parallel misalignment.
This type of misalignment can also occur in the horizontal or vertical plane.
Parallel misalignment produces both a shear force and bending moment on the coupled end of each shaft. It is important to note that equipment shafts can have angular and parallel misalignment simultaneously. Both must be considered for a successful installation. High vibration levels are produced in the radial (vertical and horizontal) directions on the bearings on each side of the coupling.