Dr Pulley works on improving scooter transmission. It designs and manufactures rollers, variators and centrifugal clutch shoes. Its products are innovative and patented, making a real difference to the automatic transmission of a modern scooter. The sliding rollers, SR as Dr. Pulley calls them, have a unique polygonal design, so that after many thousands of kilometres they still hold the same shape. They are made from high-quality nylon polymer that works very well with aluminium. The HIT centrifugal clutch shoes are built to be adjustable, covering every demand a rider may have from the automatic clutch engagement of the transmission. The Tuning Sportvario front pulley — the variator — was designed to give more direct drive to the belt and, combined with Dr. Pulley's rollers, to outperform the standard unit.