Sequential gearbox
In a sequential gearbox, as typically applied in i.e. a motorcycle gearbox, a selector drum is used to move and position the shift forks in order to engage or disengage certain gears. The traditional design of such a drum exists of a drum with several grooves running circumferential to the drum, the so called drum tracks. When rotating the drum, this results for defined angular positions in an axial movement of the selector forks in such an order that a currently driving gear is first disengaged, and after that the upcoming gear is engaged. In order to disengage, the torque requires to be removed from the drivetrain (i.e. operating the clutch and/or applying an engine cut). This interrupts the acceleration of the vehicle and causes oscillations in the drive train.

Seamless shift gearbox
A seamless shift transmission makes it possible to shift without removing the torque from the drivetrain. This results in an instantaneous shift but above all a much smoother shift. By not having to remove the load from the drivetrain, the acceleration of the vehicle is not interrupted and drivetrain oscillations are avoided. Resulting in better performance, reduced stress on drivetrain components and more driver comfort.