Roller Balancing

[Wheelman-111]

Greetings:

If you use different roller weights in the same variator, how do you set them up? Like sizes opposite? You still end up out of balance as near as I can figure...

[scooterwerx]

with a 6 roller variator, you would need 3 of each, then set them up every other, so in each little set of ramps, there would be an equal amount of weight. i never got why people do this, it seems like the 3 heavier ones would be doing most to all of the work, maybe it makes the shifting more progressive? hmmm experiment time!

[steffen707]

Yeah i don't see how this isn't counter-productive. Wouldn't it make the variator be slightly uneven? Like it would want to accelerate faster when the heavier weight is towards the bottom, then slower when the lighter weight is towards the bottom. I understand this happens many many times per minute, but still, wouldn't all 6 being same weight be best?

[808BMW]

The roller isn't really influenced by gravity (heavy vs. light roller being on top or bottom).

It's driven by centrifugal force, as the variator spins, each roller will move from the center of the variator to the edge. So as long as you have 3heavy/3light rollers, and you place them alternately, it will still be balanced.

[steffen707]

But if 3 are 13 gram and 3 are 1 gram. They're going to react differently.

[scooterwerx]

but there will still be 42g of rollers trying to expand the variator, im sure the difference wouldnt be that extreme, ive been reading up on it, the ruckus guys are all about it

[808BMW]

Well that's true...

The weights are kinda locked together (not literally) by the ramp plate, so that probably helps keep them together. 3 light weights will want to move out earlier than the heavy weights, but they really don't have enough mass to push out the variator on their own, so they'll have to weight for the heavier weights to catch up and add their mass against the ramp.

Also, a 13-1 split on weights is a bit extreme, I'd try and keep them close.

[Wheelman-111]

Greetings:

Beemer states:

3 light weights will want to move out earlier than the heavy weights, but they really don't have enough mass to push out the variator on their own,

I think you might have that backwards, but your point is taken. Uneven loading on the ramp plates. Alternating light-heavy-light is the way to go.

Werx gives it up:

ive been reading up on it, the ruckus guys are all about it

Please share?

NOBODY has offered any engineering insight as to why the ramps are angled the way they are. There is NO way to balance the rollers. If you divide the variator "pie" into quarters, you cannot draw any two lines at right angles across the diameter and achieve the same roller mass on each half. Unless the casting compensates with more metal someplace, that thing's gonna buzz. The question is: WHY?

[steffen707]

I was just using the 13 and 1 gram analogy to discuss how the differences in weight would cause something of a difference then say 6, 7 gram weights.

[steffen707]

I'll have to buy another weight kit and test this out to see what happens.

Or......somebody with a gps can graph the differences???

[scooterwerx]

wheelie man

your thinking symmetry with respect to an even number of axis. how do five spoke wheels, or even the three spokers on a scoot balance? if you divide the "pie" into thirds and draw, say, a 120 degree angle through it, itll work out. i promise!

[Fishman43]

Bump for an update. Anyone played around with different weights to see the changes?

[hollister_boy]

Yeah its called stargering the weights.

its compleatly harmless,

In my Chinese scooter i have some 4 grams and 5 grams.
and haha i can burn the tire.

[Arnadanoob]

I'm going to try to take a stab at this discussion.

First of all, remember that it's the combined weight that allows the pulley to move towards the direction of the driveface.

Lighter rollers due to their lighter mass will want to move out towards the outer edge of the variator sooner than the heavier rollers which will "want" to remain closer towards the center when they're spinning. The problem is even if the lighter rollers make contact with the ramp plate, it cannot move the variator enough (at all if we're talking 1g weights x3) until the heavier rollers "catch up" to the outer perimeter where the lighter rollers are to finally "push" the variator away from the ramp plate which allows the pulley to slide its way towards the driveface.

Here's a crude analogy. Imagine you (a heavy bowling ball) and your young kid (a light volleyball) running to get out of the house, rushing to open the front door of your house (which opens outwards). Being lighter he's going to get to the door sooner (because his lower mass also has less resistance towards movement) but might not have enough force to push the door by himself until you (big daddy) finally catches up to him and lends him a hand at opening that heavy door. The combined effort is what is needed to get things moving.

[Fishman43]

So I must have slept through that physics lecture, because intuitively I would think the heavier weights would want to spin out farther with less rotational force than the lighter weights.

That being said, what does having mixed weights gain you? Do heavier weights equal a higher top end speed, and lighter weights mean fast early exceleration?