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Dyna beads R1200GS

Actually IMHO - that's a good test. The "spin balancer" actually measures displacement forces on the center axle going through the mounted wheel. It does this when the wheel is MOVING - not when it's stationary.

Beads need suspension movement, not the forces that would generate that movement, to have a chance at working. The beads DO NOT BALANCE THE WHEEL. They may balance the effects that an out of balance wheel have on a moving suspension by changing the the coupled mass of the wheel.

An out of balance wheel will tend to compress the suspension as the heavy point is in line with the spring. When it does this the tire, for a brief bit, moves away from the beads that are at the top of the arc. For that brief bit the beads at the bottom are coupled to the wheel but the beads at the top are not. The mass changes. That's the theory as I understand it. I think I see how it can work. But....

  • how fast does the wheel need to spin?
  • how much suspension movement is needed?
  • what effect has suspension movement not associated with an out of balance wheel?
  • how well/fast to the beads react to varying wheel speeds?
  • what, if anything, do beads do to the inside of your tire?
  • since the wheel is not balanced, is there extra wear on wheel bearings?

Those are a few of the unanswered questions that keep me from using beads.
 
Let's say that dynabeads do work. Don't they all settle on the bottom of the tire
each time the bike comes to a stop? Seems like you would have a very out of
ballance tire each time you start off until you reach a speed where they would start to work.
 
Let's say that dynabeads do work. Don't they all settle on the bottom of the tire
each time the bike comes to a stop? Seems like you would have a very out of
ballance tire each time you start off until you reach a speed where they would start to work.

Very true. IIRC, the dynabead guys say the beads are working completely somewhere around 25 MPH. Low enough you don't notice the imbalance.
 
I'm open to seeing some proof. Testimonials and graphics are not proof.


So, who said the testimonials and graphics were proof of anything?

There's been an ongoing discussion of how dynabeads work with different opinions on if and how they work. The link provided an explanation from the perspective of the company that makes them. Nothing more or less.

I'll go have my beer now. :drink
 
It seems like the people who tried Dyna Beads, like them. The others want to disprove them.
 
I'm one who tried them and took them out 3 days and 300 miles later.

Why?

I've been using them for over a year, in three sets of tires (both tubed and tubeless) on my GSPD, with very good results.

Tom
 
The moving suspension part is fine - but a heavy spot will try to move outward harder then a light spot

That's the fundamental misunderstanding that many people have. The heavy spot moves IN. Think about where the mass center of an unbalanced wheel is. That's the point it's trying to rotate around. That's the point the axle is trying to follow, and it shakes the motorcycle in the process.

Tape a wheel weight inside the rim of a Frisbee and throw it. OK, maybe you don't actually need to because you know what'll happen, right?
 
That's the fundamental misunderstanding that many people have. The heavy spot moves IN. Think about where the mass center of an unbalanced wheel is. That's the point it's trying to rotate around. That's the point the axle is trying to follow, and it shakes the motorcycle in the process.

Tape a wheel weight inside the rim of a Frisbee and throw it. OK, maybe you don't actually need to because you know what'll happen, right?
As pointed out - a Frizbee doesn't have anything restricting it's movement (like an axle running through the center of it.) If it did - the weight would try to move the axle out as it rotated around it.

Back to the wheel balancer.. a dynamic wheel balancer (aka SPIN balancer, aka High-Speed-Spin-Balancer) uses sensors around the axle that measure displacement of the axle by the imbalanced wheel/tire.

http://www.gregsmithequipment.com/Atlas-WB11-Wheel-Balancer-p/atwb11.htm

How a Wheel Balancer Works:
The computer within the balancer receives the premeasured values of wheel dimensions and responds to the output of a rotational speed sensor that monitors the rotational speed of the shaft. When the required speed is reached, the mechanical system automatically decouples the powered cranking shaft from the wheel shaft so that there can be no externally applied disturbances for the subsequent measurements of imbalance. Multiple spaced transducers along the shaft determine the wheel run-out attributable to imbalances in both the inner and outer wheel rim planes and the computer provides output signals indicative of the correct balance weight and the mounting positions of the weights on the wheel rim.

Every one of them I've played with - the shaft through the balancer has some movement in it, restricted by the transducers and/or suspension of the motor driving the shaft. This movement should allow the beads to work if they work by displacement of the tire by the imbalance condition.

I can't see why this wouldn't work to test how well Dynabeads work..
 
Awesome discussion

Interesting discussion.

I guess I think they work a bit differently than everyone else. I don't think the beads optimize the suspension, but the suspension is required to initiate the distribution of the beads. Hard to say if a spin balancer has enough movement. The beads may not balance "the wheel", but they balance the rotating wheel/tire assembly when it's rotating above say 25MPH.

Here's what I was thinking.

When the bike is stopped, the beads are at the bottom of the tire (obviously).

When the tire first starts to rotate, the beads distribute evenly around the inner surface of the tire.

As speed begins to increase and the wheel heavy spot crosses the center line of the suspension, the inner surface of the tire accelerates away from the beads. The only place for the beads to go is to flow/roll along the inner surface of the tire towards the light spot of the wheel/tire assembly. Lots of beads move at first and fewer with each additional rotation.

After say 15 tire rotations (just a guess), the beads are fully distributed. They aren't evenly distributed. They are thicker directly across from the heavy spot and taper back with fewer and fewer beads around the inside surface of the tire until you have no beads at the heavy spot.

As long as you stay above 20 to 25 MPH, the force of the wheel rotating holds the beads in place and the tire/wheel assembly is balanced.

As the bike slows below 20 to 25 MPH, the beads migrate back around the inner surface of the tire (proportional to the speed drop). When that happens, the tire/wheel assembly is out of balance, but the speed is so slow you can't feel it. As the bike comes to a stop, the beads drop to the bottom of the tire.

Since you only put in 1 or 2 oz. in a motorcycle tire, there a pretty low limit to how much imbalance they can work with.

Just a thought
 
As pointed out - a Frizbee doesn't have anything restricting it's movement (like an axle running through the center of it.) If it did - the weight would try to move the axle out as it rotated around it.

It may be something you just don't get. Everyone has things they get and things they don't. Do away with the axle. You've got a OOB wheel spinning around some point. Is the heavy spot closer to that point or farther away? You really need to understand this part first.

Now put the axle back in. The axle will move with the wheel. Now put a motorcycle on that axle.

The axle of a motorcycle is not a rigid support and does not keep the wheel from following its eccentric path. If it really stayed stationary, we wouldn't need to balance wheels at all because you'd never feel the effect of the imbalance. But clearly the tail is wagging the dog to some extent when we ride.

What effect do you think actually makes the imbalance that you feel? That might be a better place to start.
 
Real world test?

Hi,
Putting theory behind us, I think the best thing for someone to do is take a tire and force it unbalanced with weights and ride the bike. Keep adding weight until you can feel the imbalance.

Now add the beads to the unbalanced tire and ride again. Did it work. Yes or No?

While I don't use them, (not sure if it would be good with TPM) most of the reports I've read are positive. I may try them on my old Turbos next time around because I hate weights on the gold wheels...

Anyway, assuming that it does work, I can see that there could be a problem of not enough beads in the tire to spread around. I would think that the texture of the inside of the tire would have a bearing on this. Smooth surface would allow a few beads to move where ever they want, but I've seen tires with patterns of shallow pockets in them which could prevent the beads from flowing like they should. More beads should allow them to fill the pockets and flow.
 
One main reason I don't use them? I change tires for seasons... Metz in the summer and Avon's in the winter... Drilling holes in a perfectly good tire to capture beads is idiotic.

The other reason? I have the equipment and I can balance often. Why play with beads when I can inspect my tires and rims when I remove them for one purpose or another. And keeping my rims clean is a purpose...
 
Hi,
Putting theory behind us, I think the best thing for someone to do is take a tire and force it unbalanced with weights and ride the bike. Keep adding weight until you can feel the imbalance.

Now add the beads to the unbalanced tire and ride again. Did it work. Yes or No?

Good idea, although you'll probably get push back that it's just an anecdotal experiment and not "scientific proof" ...

dstuckmann said:
Anyway, assuming that it does work, I can see that there could be a problem of not enough beads in the tire to spread around. I would think that the texture of the inside of the tire would have a bearing on this. Smooth surface would allow a few beads to move where ever they want, but I've seen tires with patterns of shallow pockets in them which could prevent the beads from flowing like they should. More beads should allow them to fill the pockets and flow.

The dynabead guys seem to be pretty upfront about where they work and where they don't. There's a pretty good FAQ here...
http://www.innovativebalancing.com/news.htm

BTW, no financial interest on my part with dynabeads. I've been using them for a couple years and think they've been a terrific product.
 
One main reason I don't use them? I change tires for seasons... Metz in the summer and Avon's in the winter... Drilling holes in a perfectly good tire to capture beads is idiotic.

I might be missing something here, but why would you drill a hole in your tire to capture the dynabeads?

The dynabeads aren't going anywhere. As you take the tire off, the dynabeads will stay inside the tire carcass unless you forcefully try to eject them. After the tire's off, if you stand the tire upright, the beads will all roll to the bottom of the tire. I just use a small parts brush to sweep them into a plastic spoon. It takes about 30 seconds. I put them in a ziploc bag. When the new tire goes on, after the first tire bead goes over the wheel, I snip the corner of the ziploc bag, pour the dynabeads into the new tire, and then put the second tire bead on the wheel. It's a pretty low effort, non-destructive process to reuse the dynabeads.
 
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