I have had d.b. for three hundred miles and they seem to work great. Just checked the d.b. website and they do not recommend them for "racing motorcycles" citing that the inner tire surface is too soft. d.b. says they are ok for street motorcycles though.
That video is hilarious. The bottle is vibrating like crazy. Funny how people don't see it. The difference from it flopping around wildly is apparently enough to give the impression that it isn't out of balance any more. Start the video at the one minute mark. If that's what they call balanced, no thank you. If a motorcycle's front wheel were vibrating on that same scale, the bike would be unridable.
Blake, the point is that the bottle went from vibrating wildly to barely vibrating at all. Sure, it may not be completely smooth, but this is a bottle that weighs a couple of ounces with a weight that weighs more than the bottle itself that is unbalancing it. In contrast, the percentage of weight that the average tire is out of balance in relation to the overall weight of the wheel and tire is tiny.
It seems pretty clear from the demo that the Dynabeads have the ability to make a significant improvement in the overall balance of the bottle, so why wouldn't they also have a positive effect if used for tire balancing?
All the video demonstrates is that if you run a drill with a bottle at low speeds, it wobbles, then if you run it at high speed the bottle is smooth. The beads did nothing, they didn't show the bottle without beads at the same speeds.
>>> It seems pretty clear from the demo that the Dynabeads have the ability to make a significant improvement in the overall balance of the bottle,
They don't. You've been duped. The best frauds are the one that are convincing.
>>> so why wouldn't they also have a positive effect if used for tire balancing?
Have you ever seen a wheel/tire with a 50% mass imbalance at its outer radius? That's abouth what that video showed. And exactly as Frank pointed out, with increasing speed the magnitude of vibration decreases.
It's no different a trick as the hucksters selling some "amazing" new car wax pulled. They subjected the finish of a car treated with some name brand wax to a laser beam; it blistered, smoked and peeled the paint. Then they applied their miracle wax to a "spectator's" car and subjected it to the same laser beam. Miraculously, there was no effect on the paint.
Convincing, yes? You saw it; how could it not be?
The first car was painted dark blue. The "spectator's" car was bright white. White reflects laser light almost as effectively as a mirror. The dark blue absorbs laser light. The wax had nothing to do with the outcome.
Different physics, but the huckster's con is of similar effect and intent in both.
Read rough all the huckster bead threads and weigh the science for yourself.
I don't want to lessen vibration of my wheels/tires; I want them to be balanced well enough so that they don't ever vibrate. The huckster beads cannot ever achieve that. In some circumstances they could make it worse.
Posted on Wednesday, November 02, 2011 - 08:54 am:
Blake, you keep saying that the beads don't work, but unless I've missed it, you haven't provided any evidence or explanation why they don't. The most basic thing demonstrated by the video is that the beads significantly reduced the shaking of the bottle despite a proportionally huge imbalance. What part of that video, exactly, is duping me?
Posted on Wednesday, November 02, 2011 - 10:05 am:
Well this has been an interesting debate, but the jury has deliberated for me. I intended to pull both wheels and then remove the tires last night. I was going to mount the tire paint dots opposite the wheel paint mark and try them without balance weights or Dynabeads. After wasting twenty minutes trying to loosen the rear axle without loosening the pinch bolt, not recommended, I got the rear wheel off and began to try to remove the tire. I used a large c-clamp in an attempt to try to break the bead loose and quickly convinced myself that I would need at least on more large c-clamp to be successful. Since I did not have another one or a set of motorcycle tire irons, I decided to go the traditional route and pay the $25 per tire to have them mounted and balanced. One thing I did notice is that the tape weight that was installed on my rear wheel after the last tire change was no longer on my wheel, and I never noticed any increase in vibration. Removing the front brake caliper mounting bolts was definitely the biggest p.i.t.a. of the entire process. If I had the right tools to change out the tires, I would definitely go without the dynamic balance and without the Dynabeads.
Posted on Wednesday, November 02, 2011 - 11:45 am:
Dave,
>>> Blake, you keep saying that the beads don't work, but unless I've missed it, you haven't provided any evidence or explanation why they don't.
You've indeed missed it, ignored it, refused to see it. Search thread subject titles for "dyna beads", review the discussions, then get back to me. But really, the video itself under scrutiny shows that the beads are not balancing the bottle. Any uniformly added mass would lessen the effect magnitude of vibration displacement of such an imbalance. The more total mass there is, the less deflection an imbalance will cause. Imagine the bottle made of lead. Would that same 22 gram imbalance cause the same extreme wobble? No, it wouldn't. The bottom half of the plastic bottle (the effected portion) might weigh 22 grams (0.78 ounce) itself, but probably not even close that much. Any amount of added mass (like one ounce of beads) distributed fairly evenly about the circumference will GREATLY reduce the wild extreme vibration of such a feather light bottle with such a relatively massive imbalance. Let me see a video showing no vibration.
>>> The most basic thing demonstrated by the video is that the beads significantly reduced the shaking of the bottle despite a proportionally huge imbalance.
You could fill the bottle with dung and it would have the same exact effect.
>>> What part of that video, exactly, is duping me?
The part where you are led to believe that the beads are balancing the rotating mass. The part where you are convinced that the bottle accurately represents an unbalanced wheel/tire. The part where you are convinced that the behavior of the bottle correlates to that of a wheel/tire rolling down the road (bumpy, rough, uneven...) which is also subject to both significant acceleration and deceleration not to mention being turned and leaned.
The part where you are eager to believe those who are looking to separate you from your hard-earned disposable income, versus someone who is well-qualified (professional mechanical/structural engineering analyst) and is objectively analyzing the claims and evidence. Not to mention that the claims and evidence are also corroborated by reports from an unbiased investigative journalist. See Reepicheep's post above quoting the MCN versus Beads people correspondence.
Another of the bead sellers' claims, that a spin balancer won't show the beads working because it eliminates the wobble of an imbalanced wheel/tire, is also suspect. Anyone who's ever closely observed a spin balancing procedure for an out of balance wheel/tire knows that claim is false. The tire surface of an unbalanced wheel/tire definitely goes all vibrating and wobbly at the resonant speed.
We need our own actual scientific video demonstration.
Another thing that should raise a red flag is that the beads proponent's video failed to show a control run, meaning the bottle alone absent any added imbalance weight or beads. That renders it highly suspect right from the start.
Posted on Wednesday, November 02, 2011 - 11:52 am:
I never balance my tires. Ive never had a shake. I took my tires up to be balanced once. payed $40 and one of the two had a .25oz weight on it. two weeks later I was cleaning the wheels and noticed it was gone and I could not tell. Sport motorcycle tires are so light I just dont believe that with the quality of todays tires its needed.
Posted on Wednesday, November 02, 2011 - 02:06 pm:
This has turned into an entertaining thread to watch. I too have done some wondering about these magic balancing beads... To address some of the things that have been said, the claim that a spin balancer won't show the beads working is not necessarily suspect. If the balancer was perfectly rigid, then no the beads would not work. Although I would doubt that is the case in reality. As for the demo video. The bottle is taped to a drill, ie. not mounted on its centerline. Speeds are not consistent. And so on... it is not a great demo. Clearly the bottle is not balanced at any point in the demo. But the reason for this is not only because of the beads.
In principle this type of balancing could work...with a few assumptions. 1st Steady state. 2nd Rotating object is not perfectly rigid about its rotational axis. 3rd Negligible friction between beads, and between beads/tire/wheel. 4th Inside of tire is perfectly round/smooth. 5th Ignore any resonance induced by riding conditions, suspension, etc...(this is covered by steady state assumptions) 6th Correct quantity of magic beads are in play 7th Ignore wear of tire/beads
Operating within these parameters I give you an example. Lets take a tire/wheel that is rotating about its geometric centerline. It is out of balance, and free to oscillate within the limits of suspension components. What does the tire/wheel do??? It will try to rotate about its rotational center of mass, ie. closer to the heavy side of the tire. This is why we feel the vibrations. Now lets add some of these magic beads... Where do they go? They will go to the light side of the tire. Why you ask, because the light side of the tire (the side furthest from the rotational center of mass) is rotating on a larger diameter path. And assuming there are enough beads the tire will be balanced. Thus this type of balancing is sound in principle...
That said I would not use these. Bikes are capable of high accel/decel as well as high lean angles (cruisers aside hehe). Both of which apply forces to the tire/beads that will act against the forces that are keeping the beads where they need to be. Thus driving the wheel out of balance. Also, the inside of tires are not completely smooth and may not be perfectly round. Depending on the rotational speed of the tire assembly, bumps would most likely be enough to jar the beads loose.
I think these things may be practical in some situations, but not in modern sportbikes. Now I better get back to work...
Posted on Wednesday, November 02, 2011 - 04:51 pm:
>>> the claim that a spin balancer won't show the beads working is not necessarily suspect. If the balancer was perfectly rigid,
Nothing is perfectly rigid, not a spin balancer, and certainly not a tire.
>>> then no, the beads would not work.
Then you are saying that unless a wheel/tire is vibrating, the beads won't work. Well, then how do they ever achieve and maintain balance? Answer: They cannot.
>>> Although I would doubt that is the case in reality.
Bingo. Thus the claim is suspect.
>>> In principle this type of balancing could work...with a few assumptions
Not so much, firstly because it is not balancing, if anything, it is vibration damping. Study up on the difference between the two. They are interesting topics. My graduate engineering study of them was very rewarding.
>>> And assuming there are enough beads the tire will be balanced. Thus this type of balancing is sound in principle...
Not so much. See above. Good observation concerning the amount of beads, but you've neglected the fact that if the tire were to become balanced, there'd then be no motivation for the beads to stay put and maintain balance.
You've also neglected the fact that an automobile or motorcycle wheel/tire is relatively fixed in all but one axis of vibration relative to the tire spinning. It's a much more complex problem than your thought experiment implies.
As to the video...
>>> The bottle is taped to a drill, ie. not mounted on its centerline.
I'm not seeing that. The cap looks fairly centered to me.
>>> Speeds are not consistent.
Yes, they don't run the imbalanced bottle up to a high speed, choosing instead the worst resonance speed to show the worst possible displacement.
>>> Clearly the bottle is not balanced at any point in the demo. But the reason for this is not only because of the beads.
The reason is because the beads don't balance the bottle.
Posted on Wednesday, November 02, 2011 - 05:38 pm:
>>>The more total mass there is, the less deflection an imbalance will cause. Imagine the bottle made of lead. Would that same 22 gram imbalance cause the same extreme wobble? No, it wouldn't.
Consequently, less weight would be needed to counter the imbalance.
>>>Any amount of added mass (like one ounce of beads) distributed fairly evenly about the circumference will GREATLY reduce the wild extreme vibration of such a feather light bottle with such a relatively massive imbalance. Let me see a video showing no vibration.
The weight causing the imbalance is 20 grams, so 0.71 oz. An ounce of beads is added to the bottle. That seems to make sense that the weight of the beads would need to exceed the weight of the imbalance to be able to counter it.
How much does it matter if the object being balanced is a bottle that weighs nearly nothing or a wheel/tire that weighs, for example, 10 pounds? If a 1oz static lead weight is enough to counter an imbalance, would it follow that 1oz of beads would also be sufficient to counter the imbalance? If not, why not?
>>>You could fill the bottle with dung and it would have the same exact effect.
I think not, if for no other reason than that the dung does not have the ability to easily and quickly redistribute itself along the inside of the inside circumference of the object that it is supposed to balance.
>>>The part where you are led to believe that the beads are balancing the rotating mass.
Fair enough, it sure looks to me like the beads are having a significant effect reducing the amount of vibration.
>>>The part where you are convinced that the bottle accurately represents an unbalanced wheel/tire.
Also fair enough, but why would a tire necessarily be affected differently than the bottle? There are obvious differences between the construction and layout of the inside of a motorcycle tire compared to the inside of the bottle, but why would those differences negate the potential balancing effect of the beads?
>>>The part where you are convinced that the behavior of the bottle correlates to that of a wheel/tire rolling down the road (bumpy, rough, uneven...) which is also subject to both significant acceleration and deceleration not to mention being turned and leaned.
A tire's inherent imbalance is static--if it wasn't, then static balancing with lead weights wouldn't work. So if the tire's imbalance is static, why would acceleration, lean angle, road conditions, etc, have an effect on the beads once they have redistributed themselves to positions that negate the static imbalance?
So far I've seen a video which seems to make a pretty convincing argument that the beads significantly improve balance in a bottle with a static imbalance. What I would need to convince me that the beads do not work is the following:
1) A test run on a motorcycle with a wheel so far out of balance that it causes vibration which is noticeable to the rider.
2) A test run on the same motorcycle with an appropriate amount of beads installed, in which the rider does not experience a significant improvement in the amount of noticeable vibration.
3) A test run on the same motorcycle with the beads removed and a static lead weight installed in which the rider experiences a significant improvement in the amount of noticeable vibration.
#1 would prove that there is a problem. #2 would prove that the beads cannot resolve the problem. #3 would prove that the problem can be solved by a traditional application of static lead weights.
>>>Dave Searle of MCN says: Our testing indicated that the beads are not as effective as fixed rim weights located by a spin balancer. And the amount required for a motorcycle (two ounces) is enough to noticeably affect gyroscopic inertia.
This sounds similar to what I'm referring to--I guess I'd have to see the original report to see how correct that is. However, I do question being able to notice the affect of two ounces of beads on the gyroscopic inertia of a tire. I'd honestly be surprised if I could notice the effect of eight ounces, much less two ounces. Did MCN do a blind test (with and without beads) so that there wouldn't be any influence on the rider's opinion of the effect of the beads on the motorcycle's nimbleness?
Posted on Wednesday, November 02, 2011 - 06:59 pm:
This discussion of balancing methods has been an interesting read. I work as a vibration analyst for a major electrical utility so I have a little background in balancing. My first observation with out seeing the video is that a lot of the vibration of the bottle is actually from the drill. Their claim that a it won't work in a spin balancer is correct since the balancer is not looking at tire wobble but forces put on an instrument called a vibration transducer. They are correct in that you can't balance the wheel with the beads in it since they will flow to to the area farthest from the center line in a slightly different pattern each time regardless of where the heavy spot is. Vibration displacement changes dramatically due to rpm so I would want scientific proof more than a utube video before I would put something inside my tire. Even slime tells you not to use their product in street bike tires and it would have the same effect.
Posted on Wednesday, November 02, 2011 - 09:10 pm:
>>> Consequently, less weight would be needed to counter the imbalance.
Less percentage of weight of the wheel, but not less weight. A 100 LB wheel with a 1 oz imbalance at the rim requires the exact same 1 oz compensatory wheel weighting as a 1 LB wheel with the same 1 oz imbalance at the rim.
>>> How much does it matter if the object being balanced is a bottle that weighs nearly nothing or a wheel/tire that weighs, for example, 10 pounds?
Exactly, concerning how much mass is required to correct the imbalance. My point was that the featherweight bottle was employed to exaggerate wildly the effect of the imbalance. It's one of the vital visual effects of the con. The same as the laser smoking the paint on the blue car. The viewer is fooled into thinking that the beads are balancing the wild wobble. They are not.
You know what would be informative and very interesting? To have a strobe lit video of what is really happening.
Okay, fresh dung. But I said "fill", meaning it would fill the bottle.
>>> Fair enough, it sure looks to me like the beads are having a significant effect reducing the amount of vibration.
No argument there except that they ought to have spun up the bottle faster and to a high speed like they did with the beads. The magnitude of vibration would have decreased greatly had they done so. A system or device that reduces vibration is a "damping", not balancing.
>>> why would those differences (tire on wheel on vehicle going down road versus bottle) negate the potential balancing effect of the beads?
For a number of reasons. Tire flattens at the contact patch. Acceleration and deceleration would fling beads around. Bumps would disturb the beads. A vehicle wheel is relatively restrained to allow radial motion along only one axis, pretty close to up and down usually. How does that play with the beaders' theory that the wheel needs to be unconstrained in order to work?
>>> A tire's inherent imbalance is static
When the tire spins, a static imbalance becomes dynamic. We don't notice it much until the rate of spin comes close to the natural frequency of the wheel/tire/suspension assembly. That is when a damping system like some loose mass inside the tire can help. But it's a bandaid at best and fails in a number of scenarios as already mentioned.
Posted on Wednesday, November 02, 2011 - 10:57 pm:
They beads, or any similar spherical ballast material like airsoft pellets work great in the 4x4 world. Granted the wheel rpms are lower and the acceleration/deceleration is slower, but they do work. Very well.
Centramatic balancers operate on the same principle and get rave reviews.
I never considered them for a bike - tire tolerences are so much better.
Posted on Wednesday, November 02, 2011 - 11:18 pm:
I'm reminded of all the gun related "solutions" that don't work, and often are looking for a problem to solve.
I agree with many here, for a solution that is so unconventional, I would need some real proof that it actually works, not a demo that is too unrelated to matter, and anecdotal evidence that is too bias to take seriously
So many are anxious for an easy solution, and will rush to unconventional solutions, thinking they've outsmarted everyone else.
Sprint: I did try removing the wheel without pulling the caliper. I didn't see how it was going to work and since I had read the service manual, just figured that it had to come off. I am curious to know how you get it off without removing the caliper?
That trick does not work depending on what exhaust you have. The slots on the caliper are so you can easily remove the caliper. It still is easier to remove the caliper than to remove the fender, then deal with positioning the wheel right, hoping you can lift it clear of the caliper and still have room to get around the muffler.
To support Blake's stance, think of this in terms of unsprung mass... The lighter the rotating assembly the easier it is to react/comply with surface conditions. By adding mass (beads) to the tire, you slows wheels ability to response to surface conditions.
Try this experiment - put a wad of paper in one hand and a brick in the other and shake both back and forth. You'll find that A) the brick hand will oscillate much slower with equal effort, or B) you'll have to shake the brick hand with much more effort to oscillate at the same rate.
So in this situation, the added beads are providing more mass which affects the wheels frequency and amplitude of vibration. Doesn't really balance it, just damps it.
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