The main role in tuning a variomatic scooter is weight. Rule of thumb: the lighter your roller set, the more turns are needed to push outward rolls through centrifugal motion to set gear changes in motion. Heavier rollers must lower the rpm to initiate this process. This means that if your scooter rolls lighter it will need higher rotation speeds to start moving. Heavier rollers allow you to start moving at lower rpm. Each driver will have to discover what rev level is right for them. A number of factors go into this decision: the degree of tuning, the weight of the drivers, what weight (of rolls) are optimal, etc. Knowing the overabundance of unsuitable material on the market, we can only recommend various rolls from renowned POLINI studios and MALOSSI. Their products are made to the strictest standards, are of the highest quality and are durable - and still affordable! Here are the most common formats: Engine type: MINARELLI 15x12, MORINI 17x12/KYMCO/PEUGEOT/HONDA/PIAGGIO/GILERA -> `98 16x13, PIAGGIO / GILERA `98 -> 19x15, 5 Sport Variators: POLINI / MALOSSI 16x13, 15x12 HEBO PERFORMANCE 17x12/TOP SIP-TIP! By changing variator rollers, each scooter can be tuned exactly to its engine performance or driving conditions. What you should note: The more aggressive your engine is tuned, the more sensitive it reacts to weight changes in the lists. Be careful not to work with weights that are too different! Remember: exact varied tuning is really necessary so that the engine doesn't waste its performance under unnecessary rpm (weights too light) or through gear changes too early (weights too heavy), which won't get you any acceleration.