Speed Variator Basics

This article is to help you learn what a speed variator is and what it does. To the left you can see a couple of the "speed" variators that we have tested for the Ruckus. Yes, unlike other shops we have tested more variators than you could count. We spend loads of money on R&D at Battlescooter.

It seems like I answer the same questions about the variator all day, every day. It's really what drove me to write another article on drive mods (^_^)

Let's start by listing some myths that are passed as facts every day.

1. "The only difference between variators is the angle of the drive face."

The variator is really complex and can make or break performance. Choosing the right one is not tricky if you follow the rules. Read "Make it faster?" before you spend any money.

To the left you can see our new baby, the Daytona Drag. It has long roller ramps and the rollers get closer to the crank than the Posh part to the right.

The Posh looks larger in diameter but don't let that fool you, size isn't everything. The belt doesn't go all the way to the top of many larger diameter variators. They make them bigger to trick you.

Some people will tell you variators like the Posh and Polini are faster on the top end but it's ultimately in the rest of your setup. One thing is for sure on scooters like the Ruckus and Metropolitan, that is lugging the motor will put you in the back of the pack. Sure if the planets align and you have the wind at your back it's possible they could be faster but I ride in the real world and that stuff never happens.

You really want to start out in as low a gear possible. If the variator lets the belt touch the crank you can't get any better than that. By the rollers getting closer to the crank the belt does too.

In the picture you see the variator with the roller weights all the way at the bottom of the ramps (close to the crank).

The Daytona Drag and KN Kikaku variators both let the belt touch the crank.

The belt moves up the drive face as the rollers are forced up the ramp by the rise in engine RPM. How the belt moves up is controlled by a couple factors.

The ramp floor, ramp plate and variator (movable drive face) angles as well as actual roller weight all have an impact. Steeper angles require more roller weight than the less steep ramps.

The distance between the movable drive face and ramp floor have just as much of an effect on the ratio as the variator diameter and ramp length. I know that was a lot to get your head around but read it until this sinks in. Just picture if the ramp ends away from the actual drive face more than another variator the belt will be forced higher up the face by the roller weights.

In this picture you can see that extreme played out. Of course how the fixed and moveable drive faces fit together is the limiting factor.

This is what the variator looks like when the engine is maxed out as well as the rollers.

It's also something that kills another load people dump on the web. Your roller weights can only go so far. If your weights are reaching the top of the ramps adding heavier weights won't make you faster. Yes, if your scooter is messed up adding heavy weights could make it faster.

This heavy roller myth is just maddening. I cringe every time someone buys 8gram weights for a bike that came with 7gram.

The only caveat for this one is if you are making loads of power and you need to calm the motor. Heavy weights calm the motor. This only applies to people who are taching out in less than a second. If your scooter is messed up calming the motor will keep it from revving up, good if your jetting is wrong or something is broken.

Here you can see the KN and Daytona Drag face to face. Both of these variators (movable drive faces) are the same size. They also both share similar ramp lengths. I'm building a case here so please bare with me.

 Trust me things are about to get interesting... At least they are if you care at all about going fast.

This is the Daytona Drag in my trusty tool. You can see the gap towards the outer diameter of the face. The KN made that profile. The KN has a flatter face than the Daytona. The KN has less of an angle. The Posh came in with the exact same face angle as the Daytona. The next pic will confuse you more if you're not already.

Just as with the ramps, less angle means you will need more roller weight to do the same job.

To the left you can see some pretty amazing stuff and why I picked the variators I did. All three of these variators are shown with the rollers maxed out and with the same drive boss (spacer).

 The overall ratio of the Daytona is higher than the Posh and both are higher than the low geared KN. The Daytona actually pushes the belt up slightly past the diameter of the variator. This is OK since that part of the belt doesn't do much for grip.

The ramp length to compare.

1. Daytona Drag 26mm

2. Posh               24.5mm

3. KN-Kikaku        26mm

The Dayonta Drag and KN both have the same ramp length which makes them work better but the Daytona Drag has different ramp angles allowing it to raise that belt just a little more.

So with this information you should be able to make a good decision as to which variator will keep your engine in the correct power band. That's really what it comes down to. You don't need the variator someone says is good. You need the variator that has characteristics that match your scoot, riding habits and use. That said they are all very similar in performance. Any variator is better than stock. If you choose the right one for you it will be much better than stock.