Dr. Pulley Sliding Weights 25mm X 22mmCOMPATIBILITY: Aprilia – Atlantic 500, Scarabeo 500Gilera – Nexus 500Malaguti – Spider 500Piaggio – Beverly (BV) 500, X9 500SYM – RV250, Citycom 300iWe highly recommend that you begin by upgrading the variator roller weights before engaging in any performance upgrades. This is the simplest of upgrades and the least expensive. This is a minimal investment and offers a maximum return.The main rule for tuning variators is the lighter the roller the more rpm’s are needed to push the rolls outwards through centrifugal motion to set the gear change in motion. Heavier roller weights need lower rpm’s to start moving.Heavier roller weights = slower take-off speed, more acceleration = higher maximum speed.Lighter roller weights = faster take-off speed, less acceleration = lower achievable speed. The right balance is an individual choice since a scooter racer will want heavier weights to achieve a higher overall speed so that they might be faster at full thro