Ducati Monster Forum

Anyone use these?

http://www.innovativebalancing.com/ (http://www.innovativebalancing.com/)

http://www.innovativebalancing.com/motorcycle.htm (http://www.innovativebalancing.com/motorcycle.htm)

http://www.compacc.com/p/Dyna-Bead-Bike-Packs/1714002 (http://www.compacc.com/p/Dyna-Bead-Bike-Packs/1714002)

There's a ton of discussion over on ADVRider, with believers and naysayers duking it out.  An engineer by trade, I am half tempted to create a Verification & Validation matrix, write a test plan, and put these things through their paces.  Wish I had the time.  In the meantime, I'm just curious as to whether any of the local Ducati-ridin' ruffians have used these.

Ride safe!  [moto] [thumbsup]

I use them in the tires of my airplane which takes off from the conveyor belt in my back yard.

I'm no engineer or physics major, but won't these pile up in one spot as the wheel builds up centrifugal force?

I'm no engineer or physics major, but won't these pile up in one spot as the wheel builds up centrifugal force?

My thoughts exactly.  A friend of mine who used to race motocross used to put ATF in his tires to 'self-balance' them.  I think both the ATF and these beads would pass the basic wheel balance test: spin the wheel and it stops in a different spot.  Balanced, right?  I think it's just doing that because the friction of something moving inside the wheel makes it stop in different places.

Lets say you have a tire that is perfectly balanced an a wheel that is way out of balance. Instead of slapping weight on the wheel you use these things instead. At a stop, these beads would all be piled at the bottom of the tire and the wheel and tire would likely not be in balance. As you speed up, the beads begin to get distributed throughout the tire and ultimate centripetal acceleration holds them against the tire carcass. Now the only way I could see that the majority of the beads would go to the side of the tire that needs extra weight would be if somehow, the unbalanced wheel oscillation shook the beads to the required spot. The problem is, the largest rotational moment is going to be focused at the point were the wheel is heavier and logic would tell me that the beads would want to find their way there making the balance even worse. Think of one of those old style party noise makers that you spin around on the handle. If you fill that thing with beads, they aren't going to move to the opposite side of the spinner and balance the whole thing out.

I'm no engineer or physics major, but won't these pile up in one spot as the wheel builds up centrifugal force?

As you speed up, the beads begin to get distributed throughout the tire and ultimate centripetal acceleration holds them against the tire carcass.

well if you want to split hairs, centrifugal force isnt  really a force. ;)

well if you want to split hairs, centrifugal force isnt  really a force. ;)

That's why I said acceleration. I know someone would bring it up.

Ok, so looks like it does work.  Like many things in physics it's the opposite of my first instinct.  Looks like something useful for wheels that might pick up mud/dirt/ice but I don't need none for my moto thanks.

Scott

That video is awesome. I love science. So it looks like these would actually work. Although I wonder about low speeds - it seems like without the magnet, the wheel in the video shuddered more with the balancer on it until it got up to speed than without the balancer.

Still - very interesting stuff!

Anyone use these?

i woudnt say that yet. like all "demonstrations" this one isnt even close to the actual product.

Well to resurrect this old thread. I didn't realize it was almost a year ago that we talked about this.
So I put some new Bridgestone BT021s on the ST. I hadn't driven the ST in a bit due to working on it etc.
Upon driving it for the last couple thousand miles it had a vibration in the bars. nothing terrible, just a vibe is all.
I couldn't remember if it was always there or not. After reading this last year I had wanted to try these and just
never got around to it. I was walking to the guys at Traxion Dynamics about fork parts and noticed they were
carrying the dynabeads. I asked about them and they said they had played with the beads with a shot GL tire.
They said the beads balanced it perfectly and that sold them on the product. Long story short I put the beads
in the tires and the vibe is gone. Even at low speeds of 25-35mph it rides now smooth as glass. No vibe in the bars
or anything. Now we'll just see how the tires wear with the beads in them. So based on my experience they beads work
at low speeds on non problamatic tires. I was suprised.

Snake oil for several reasons.

I am skeptical that most riders under 75mph even benefit from traditional wheel balancing.  Modern mc rims and tires are pretty damn good to start with.  I haven't changed my stock weights on my Monster since owning it, and going through 4 sets of tires.  I have a simple balancer, but haven't used it since the first tire change.


mitt

Lets hear them. Either they work, or my SMT has perfectly balanced rims and tires out of the box.

First off, what happens when you change the rotational velocity of a tire which contains anything not attached to the tire? That's right, the object(s) maintain their momentum--Newton's first law. For the same of keeping typing easier, we'll refer to the wheel/tire combo as simply "the wheel".

Say you have a wheel that is out of balance. We'll call the heavy point "angle 0" and say that it's 1 gram and 8 inches from the axis of rotation. Now if dynabeads were to work, they would need to be exactly one gram, and would need to sit directly across from the heavy point, at 180 degrees away, and at the same distance from the axis of rotation. Say they actually do this, and sit at this point with that mass while the wheel is rotating at, say, 200 RPMs: what happens when you change the wheel's angular velocity? That's right, things inside the wheel move in relation to the wheel. If the wheel decelerates, things inside of it will move in the direction of rotation until friction and other losses reduce their velocity. During this period, the wheel will be out of balance. The same goes for acceleration of the wheel, in which case the contents, such as beads, will go backward in relation to the wheel, again putting it out of balance. So every time you change your speed, your wheels are going out of balance.

Secondly, centripetal force. While rotating, any mass within the wheel won't gravitate toward the lightest point but, rather, will try to continue along a straight path in the direction that it is alreadly traveling. However, the tire prevents the beads from doing this and holds them back. Because of this, they will tend toward the point furthest from the axis of rotation, not the point of least mass.

Thirdly, mass versus distance. Any mass further from the axis of rotation will have more of an effect on balance than an equal mass closer to the axis. Well dynabeads can't magically create mass from nothing. So what if you need more mass to balance your wheel than you added in dyna beads? At best, they'll sit at the outer part of the inner surface of the tire. If there isn't enough mass, they simply can't work any more than a perpetual motion machine could. If there's too much mass in dynabeads, where does the excess go? The same supposed force that causes bead #1 to go where it needs to would also cause bead #300 to go to the same place. The only thing stopping them is that they can't occupy the same space, and therefore they would clump.

So why does it seem to work for some people? Simple. Most wheel/tire combinations aren't far enough out of balance for a rider/driver to notice. You can put absolutely nothing on them and they'll seem to be fine. If dynabeads worked, so would oil. You could literally put an equivalent mass of oil in your tire and it would do the same thing for cheaper.

If they did work, and that's a big "if", you could get literally the same effect by putting a fluid in your tires.  Plus, if you have an imbalance greater than the total mass of the dynabeads, they still couldn't work even if they did magically stay on the exact opposite side from it.

should be a very simple issue.  put them in a new tire and run them on a balancing machine.

Read Visceral's post. A balancing machine leaves out the suspension action, which is critical.

Yes, but it would at least show whether or not they are doing anything at all.  Wheels are not balanced on a suspension, they are balanced on a fixed axle.  If the beads will balance a tire on a fixed axle then they do have SOME value.

Wheels with weights are balanced on a fixed axle, not those using the beads. If the suspension action is required to allow the beads to orient correctly, then testing them on a balancing machine with a fixed axle is useless.

The laws of physics, for one.  And rims and tires don't have to be perfectly balanced in order to feel balanced.  Most automotive (and bike) suspension systems have a natural resonance frequency which coincides with a specific rotational speed (usually anywhere from 50-80 MPH, depending upon a number of factors.)  Meaning you won't necessarily feel it as being out of balance at lower or higher speeds.

One reason they don't work is simple momentum.  Any time you change the rotational speed of your wheel, Newton's first law kicks in.  Meaning anything within the tire will attempt to continue going the direction and speed it was already traveling.  Assuming that they were in a position so as to balance the wheel at a steady speed, upon deceleration the beads/dust/water/whatever you have in there will continue in the direction of rotation until friction slows them down to the wheel's speed.  Conversely, any time you accelerate, they will shift backward in relation to the tire until friction speeds them up to the wheel's speed.

This isn't a problem for traditional weights as they're fixed to the wheel.  And unlike weights, they can't address lateral imbalances at all.

If they did work, and that's a big "if", you could get literally the same effect by putting a fluid in your tires.  Plus, if you have an imbalance greater than the total mass of the dynabeads, they still couldn't work even if they did magically stay on the exact opposite side from it.

To avoid typing everything all over again, here's my post from another forum:

If I ever have an unsolvable wheel balance problem, I'll give them a try.  They have worked in real-world trials.  Right now I have no such problem, and hence no need for them.  We'll see what happens in a few thousand miles when my tires need changed.

Tiz,
you are comparing apples to oranges though.
You are comparing static vs dynamic balancing agents.
Static being lead weights, they sit on the rim and balance the wheel, whether on a fixed axle
or a suspended axle.
Dynamic being the beads, because the can move within the tire carcass. On a fixed axle they will
do nothing. The suspension movement allows the beads to distribute away from the heavy
side of the tire, the beads don't work without suspension.

Tiz,
you are comparing apples to oranges though.
You are comparing static vs dynamic balancing agents.
Static being lead weights, they sit on the rim and balance the wheel, whether on a fixed axle
or a suspended axle.
Dynamic being the beads, because the can move within the tire carcass. On a fixed axle they will
do nothing. The suspension movement allows the beads to distribute away from the heavy
side of the tire, the beads don't work without suspension.

should be a very simple issue.  put them in a new tire and run them on a balancing machine.

my point was that if they balance a tire using a traditional method of checking balance, then they should at least perform as well as the traditional method of balancing said tire.

similar concept in this video:demonstration using a motor with a simulated suspension

How Centramatic Balancers Work (http://www.youtube.com/watch?v=skY6qvzpNXI&feature=related#normal)