The Malossi Over Range kit comes with 128mm pulleys, which provide good traction and improved top speed. This system is really great for tuned scooters. The kit includes the following parts: V-belt, overzize pulleys and variator. No milling of the kickstarter shield or engine block is required to install this kit. A set of rollers is included for this variator. The roller size is 16X13. The oversize kit fits cranks with beams (16mm axle), but is also available for cranks with 13mm axle (S-M-6112812)