Dr. Pulley Variator Slides SP2012-AA Dr. Pulley Variator Slides for the Kymco Downtown 300i. The Slide Pieces in the variator are equally as important as the rollers. It is highly recommended to change the slide pieces to coincide with the rollers. The Dr. Pulley Variator Slides are made of the same abrasion-resistant nylon as the Dr. Pulley Roller Weights, which promises a long life.