The driving pulley has a fully clutched mode of operation where a drivebelt and a driveshaft are coupled together in a torque transmitting engagement and also has an unclutched mode of operation where there is substantially no torque transmitting engagement between the drive belt and the driveshaft. The driving pulley comprises at least one transitional clutch spring that is in a first position when the driving pulley is in the unclutched mode of operation and that is in a second position when the driving pulley is in the fully clutched mode of operation. The at least one transitional clutch spring remains substantially in its second position regardless of the relative axial distance between the sheaves when the driving pulley is in the fully clutched mode of operation. A method of operating a driving pulley is also disclosed. The proposed concept provides a smoother engagement during the transition from the unclutched mode to the fully clutched mode.