Hey MO! I want to get some more speed out of my scoot, but I don’t want to spend much money. I’ve heard that by changing the variator roller weights you can do this the most economically. Is this right? and if so, what weight should I go with? -cheapskate in Baltimore
Yes, rollers are an economical way of increasing performance, however, it comes with a compromise as any performance upgrades do. The over simplified explanation that is very common is that heavier weights give you more top speed, and lighter weights more take off. This is true to a point, but not really. The variator weights control what is called the “constant engine speed”. I’m sure you’ve noticed when you give your scoot full throttle it holds a certain engine speed while the vehicle accelerates. The variator controls this engine speed. If your engine is above it’s maximum torque because of too light of of weight, it will not accelerate like it could. If your engine is below it’s maximium torque because of too heavy of weight, it also will not accelerate well as it will bog.
So, this being said, you can actually gain top speed AND acceleration by lightening the rollers. This is true for a number of reasons. Your engine has a certain engine speed, RPM, that is it’s most powerful and most efficient, this is called the torque peak. You cannot get maximum performance without being at this RPM. Second, remember that the variator get to it’s maximum contraction almost immediately upon acceleration, and holds there, it’s the rear pulley that slowly contracts as rear wheel speed increase, thereby increasing the ratio between engine and wheel, making for more road speed.
To conclude and simplify: lighter rollers increase the “constant engine speed”, and heavier rollers decrease it.