Dyna Beads - Do they work? If so, how?

[Fred W]

This topic was recently brought up in another tire balancing thread. I thought this may be worthy of discussion on a scale similar to the Can an Airplane Take-off from a Conveyor Belt thread a few years back.

So, what's the real deal with these things. I know there are a bunch of people that claim all kinds of experience with them and they insist they work. But do they? What is the science behind them? While this has been discussed in the past (often) I have never seen an adequate explanation on how these things actually do what they say (if the do)

The real question comes down to the physics. How would the beads migrate to the lightest spot in the tire/wheel to offset its inherent imbalance?

The manufacturers say it is centripetal force of the inside of the tire, but I do not see how that would work to move the beads to the lightest spot. If anything, to my way of thinking, on a tire/wheel that is severely mis-balanced the heaviest spot would be forced further from the axle by centrifugal force which would also allow the beads to follow suit.

What am I missing?

 

[ionbeam]

Brought to you directly from the people that are trying to sell you something:

I wonder why these aren't used in motor sports...

 

[Fred W]

It is frame #3 that I am having trouble with. What magic causes the beads to go to the opposite side?

Here's a you tub demo from Dyna Beads that shows them working. I just don't get how.

 

[John d]

Fred,

Bullshit baffles brains. Stick with lead!

 

[GeorgiaRoller]

Yes they work. I had them on my last bike and they worked great for several thousands of miles.

It is frame #3 that I am having trouble with. What magic causes the beads to go to the opposite side?

I know your mind wants to understand all things technical Fred, but all I know is I put the appropriate amount in my tire per Dynabeads listed tire size chart, and they felt perfectly balanced. I actually forgotten about Dynabeads & haven't used them on my FJR yet. I really could care less if its a metal tab or dynabeads...as long as they feel in balance when I ride is all I care about.

Email Bill Nye the science guy if you can't sleep at night because of this mind cramping paradigm.

 

[RaYzerman19]

So let's say you have a tire that's 20 grams off balance, seems to me you'd need 20 grams of off-setting weight in there somewhere....... yet they say just put in x amount based on the size of your tire. I'll bet it's not 20 grams (admittedly I don't know how much they weigh)....... so it's impossible the beads would work in that situation. Minor imbalances maybe, because chances are you don't notice those anyway (bike tires do not have that much mass, have to be off a fair bit for you to notice). I'm not buyin'. I'll stick with lead (which is disappearing, they're all "environmentally friendly" steel now).

I'm also voting NEPRT and lock the thread to save us all a bunch of time. There are many posts on other forums that end up the same old way. Debate is fruitless. Those that believe do, and those that don't won't.

 

[GeorgiaRoller]

You guys make stuff way to complicated. THEY WORK!

Google...Isaac Newton + law of interia

Oh wait...you won't buy that either! And Gravity is a scam too! Aye Carrumba

 

[08FJR4ME]

Nope they don't work. Seen it with my own eyes. Due to the moisture in the tire most of them were all stuck to the inside walls.

Confirmed while changing tires for my freinds VTX 1300.

Dave

 

[Fred W]

GR,

You have answered the first question of the two posed. You say they work. I will allow you that as your (and other people's) empirical evidence supports it.

Now, tell me how they work. I understand the Laws of Inertia and that doesn't answer that question. I'm guessing from your answer that you do not know why they work either.

 

[Fly Bye]

Some say they work while others say they don't work.

At this point I'll stay with the tried and true.

Good tires, proper psi, proper balancing with lead weights.

I am an advocate of the KISS principle.

 

[FJRay]

I have a CT on my Wing and it has beads in it. I dismounted it and took them out and felt no change so I put them back in cause it seemd like the thing to do. I have dismounted a number of tires and found them in a wad stuck to the tire but the customer said there was no vibration. I don't see how 2oz of crap stuck in one place could not cause a problem. Maybe people can't feel imbalance in thier bike.

Centramatics are a similar system that some swear by and others swear at. Same principle different method. I remember in the 60's you could buy automatic balancers from JC Whitney that were supposed to do the same thing. I would leave them off to see if anybody complained but it never happened.

I think the answer is that if you paid for them you have to say they work or you'll look dumb. If you didn't pay for they then you get to knock them. I still use weights but not lead ones cause my supplier doesn't sell them anymore so you have to use more to do the same job.

 

[2fjr]

I don't know how they work. I do know I don't want to deal with the little bastards when they dump all over the place when I change a tire. That's the extent of what I need to know, but I look forward to seeing a convincing demo.

 

[Justin]

According to my internet research, they work, and they don't work.

 

[SFCJCA]

According to my internet research, they work, and they don't work.

I believe you are correct.

 

[ionbeam]

How would you feel about finding this when you go to change your tires?

And, is this a tire trying to self balance?

 

[Fred W]

Rubber pearls.

 

[Road_Runner]

So far I have recycled the beads through two tire changes and they have been in perfect condition. No gooey ball 'o beads or anything. As recommended, I don't use anything gooey as lube to mount the tire. I don't notice any imbalance with them in, but it may be that the wheels are not imbalanced enough for me to notice in the first place.

Motorcycle Consumer News looked into this. They checked the balance on a balancing machine, put the beads then put the wheel back on the machine resulting in minimal reduction in imbalance. They also noted that the beads actually caused an undesirable gyroscopic effect. It's in the Feb 2010 issue if anyone has back issues.

Even if they do work they are a PITA to use, so I can't recommend them and instead would recommend a static balancer.

 

[DarkStar]

An option instead of buying Dyna Beads is to pick up a bottle of airsoft pellets... I bought a bottle of 2k heavyweight airsoft pellets, .25 gram, for $7. The pellets are all consistently sized and smooth and they're large enough they won't get stuck in a bit of moisture should it be in the tire... 115 .25 gram pellets = 1 ounce... 1 ounce in the front tire, 2 ounces in the rear, other than sounding silly rolling around in the garage they really do seem to balance the tires well, I've used the pellets on all the bikes for the last several years, so far I see no reason to change back to static balancing...

 

[rushes]

I've never tried them so I can't say if they work or not.

But...

My thinking is if a tire is heavy on one side, centrifugal force will sling it further from axle centerline. Anything loose inside the tire would roll to that spot and only make it worse?

Probably why I never thought about trying them.

The only explanation I can come up with for the people who swear they work, is they may provide a damping effect on the vibration. A kind of a shock absorber in there to soften the shake?

Just a WAG.....