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Old 08-28-2013, 07:29 AM   #76
gravityisnotmyfriend
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There may actually be something to this



How it works? I haven't a clue. But that video sure makes it look like they do. Fascinating. I'd still like to know the principle behind how they function.
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Old 08-28-2013, 08:29 AM   #77
SgtDuster
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Quote:
Originally Posted by gravityisnotmyfriend View Post
There may actually be something to this



How it works? I haven't a clue. But that video sure makes it look like they do. Fascinating. I'd still like to know the principle behind how they function.
Well, using this setup as a "proof" is like using a video of a submarine to explain how a plane works.


Some principles are similar but they are far from being identical in how they work. So the demonstration is irrelevant to me.
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Old 08-28-2013, 09:32 AM   #78
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So, here's my failure at understanding. The model in my head used the center of the wheel as a fixed location. If the axle is held stationary, dynabeads can't and wont' work. But, the axle is not rigid. It's allowed to move up and down.

The theory is that the heavy side of the wheel doesn't pull the tread away from the axle (like I was envisioning), it pulls the whole wheel toward the heavy side. That would move the beads to the lighter side. And eventually even out the whole system.

If one side of the tire is heavier than the other, CG of the tire won't be the same as the geometric center. It will try to rotate around the CG and that's what causes vibrations. That movement caused by the CG not being at the axle is what positions the beads correctly so that the CG and geometric center are the same.

At least I understand the theory behind it.
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Old 08-28-2013, 11:32 AM   #79
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Just had Dynabeads installed on the front tire on my DL650. I am a believer. I don't remember ever feeling the bike so smooth. I will get them again.
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Old 08-28-2013, 12:21 PM   #80
disston
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I have had Dyna Beads in the front tire of my 1975 R90/6 for over a year. They work pretty much the same as the video with a plastic bottle on an electric drill. I sometimes notice a little bit of wobble just when starting off at a slow speed but it is very quickly over and the front end is smooth as I could want it to be. No wobble when later slowing down because the beads maintain the position they have found. The small wobble is only on acceleration and take off.

This past Summer I had a new tire mounted on the rear and was going to add Dyna Beads when I got it home but forgot to tell the tire guy at the new dealership near me who mounted the tire and he had already balanced the wheel. So I have Dyna Beads on the front and weights on the rear. Everything works just fine.
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Old 08-28-2013, 01:03 PM   #81
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As I already said, I have no horse in this race and I don't really care for these beads but I'm always willing to learn something. So here's my contribution to stir up the nest.


Here's a vid I saw years ago but forgot about.



Maybe it could help to clarify the whole thing a bit. It doesn't show everything but it's a start.
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Old 08-29-2013, 05:31 PM   #82
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Originally Posted by El Gato View Post
You're either a troll or work for Dynabeads. If you really teach Physics, you'd understand the difference between something with a rigid circumference spinning suspended on a fixed axis (washing machine) and something that has a contact patch that's constantly moving and deforming, thus dislodging the beads, all while also oscillating vertically due to road vibration, bumps, etc. This whole "it's Physics, stupid" argument is old, and it's not proof of anything. If you really teach Physics, then *prove* that it works (hint, Dynabeads has yet to be able to do this), rather than swinging your dick and expecting me to be impressed.
This. There's so much going on dynamically between the shape of the tire, the flat spot that occurs 11 times a second at 60mph, and the bike's lean (not to mention a sudden application of the brakes or the surface imperfections inside the tire) that the "washing machine" comparison is laughable.


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Old 08-29-2013, 06:50 PM   #83
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Quote:
Originally Posted by '05Train View Post
This. There's so much going on dynamically between the shape of the tire, the flat spot that occurs 11 times a second at 60mph, and the bike's lean (not to mention a sudden application of the brakes or the surface imperfections inside the tire) that the "washing machine" comparison is laughable.


Sent from my iPad, probably while I'm pooping.
So, the beads can't possibly work in a motorcycle tire?
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Old 08-29-2013, 07:38 PM   #84
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What really convinced me is when I bought an old GL500 a couple years ago the 16 year old front tire (tubeless) was badly out of balance. I removed the weights and it was just as bad. Broke one side of the bead and dumped in a handful of airsoft BBs, pumped it up and took it for a ride. Smooth as silk. Now I use them in all my tubeless motorcycle tires. They're cheap and easy so why not?
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Old 08-29-2013, 08:26 PM   #85
gravityisnotmyfriend
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Quote:
Originally Posted by SgtDuster View Post
Well, using this setup as a "proof" is like using a video of a submarine to explain how a plane works.


Some principles are similar but they are far from being identical in how they work. So the demonstration is irrelevant to me.
Nothing to do with Dynabeads - just wanted to point out how absurd this statement is. The airfoil on a plane's wing and hydrofoil on a submarine's fins actually are identical in how they work. Bernoulli's principle works the same on all in-compressible fluids and is exactly what both things SgtDuster mentions rely upon to work.

This is of course assuming you're talking about subsonic aircraft. When a plane goes trans-sonic or supersonic they can no longer be compared to a submarine. But, up until that point - they are IDENTICAL in how they work.

Yes, I did work as an aerospace engineer for several years. Why do you ask?
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Old 10-12-2013, 08:13 PM   #86
ben2go
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I just installed new tires,tubes,and rim strips.I put the dot inline with the valve stem.While I was at it,I added 2oz of beads to each tube as recommended.I now have serious wheel hop front and rear.At 45 to 55 mph,I get head shake to the point of a tank slapper, if I even think about lifting a hand off the bars.Before I installed the tires,I checked my spokes and rim run out.Everything was in good condition.I even checked my steering bearings and wheel bearings.I did remove the spoke weights as recommended.I am also running the recommended 33/36psi air pressure that's on my bikes data sticker.It almost feels like the beads are moving to one spot and staying there causing the hop.I really don't want to have to tear down my bike again.I have always done static balances on my wheels and have always had smooth running bikes until now.I don't know whether to add more beads or just rip it apart and do a static balance.I'm not sure if I can even get the beads out of the tubes.Any recommendations?
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Old 11-27-2013, 12:52 PM   #87
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Hi all,

I stumbled onto this thread while researching tire pressure monitors. Although this thread seems a bit dormant, I thought I should add my two cents worth.

I actually used Dynabeads on my Tundra when it had a set of 6 ply Toyos, and the dam*ed tires wouldn't balance out. Toyo may make good hi-perf tires but their truck tires leave a lot to be desired. Anyway, the Dynabeads did help somewhat but there are a couple of downsides you may want to know about before using them.

First, pouring them into the tire via the valve stem can be tedious and time consuming because the beads can exhibit a static charge that clumps them. I kept touching the stem with the edge of an oscillating electric sander (without the paper of course) and the vibration helped the beads pour in. Second, removing the tire later on guarantees your beads will run all over the place unless you tell Ignatz the tire guy to be careful. Even then, he's unlikely to go to the trouble of scooping them out and saving them for a new tire.

Third, you absolutely cannot ever use a quicky tire puncture slime sealant. Do so, and you'll clump the beads together and cause the mother of all imbalances. And if you have a puncture repair that results in exposed cement inside the tire, be aware that beads could stick to that as well. In theory, the remaining Dynabeads would balance that out, but still.... Fourth, TPMS! Over time, I don't know if Dynabeads would affect internal tire sensors but it's certainly something to think about. Fifth, you'll need to replace the little metal tire valves with those that are designed to block the beads from entering the valve stem. I recall that Dynabeads sells them. And finally, sixth, once inside, if the Dynabeads still don't adequately solve your tire balance problem, know that you can't resort to a conventional balancing until you've cleaned out the beads. In for a penny, in for a Dynapound.

Bottomline, I thought they helped balance my very lumpy Toyos. They weren't the miracle I'd hoped, possibly because the tires had an inner/outer imbalance that the beads couldn't adapt to. Motorcycle tires shouldn't have that problem. My take on Dynabeads is that they are best suited for large tire applications such as on semi trucks where imbalances can be significant, glass smooth operation isn't essential or obtainable, and repeated conventional rebalancing isn't cost effective. Which isn't to say that those who have used Dynabeads in MC tires haven't benefited.

Like I say, just my two cents.
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Old 11-27-2013, 12:57 PM   #88
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[QUOTE=gravityisnotmyfriend;22214599 The airfoil on a plane's wing and hydrofoil on a submarine's fins actually are identical in how they work. Bernoulli's principle works the same on all in-compressible fluids and is exactly what both things SgtDuster mentions rely upon to work.


Yes, I did work as an aerospace engineer for several years. Why do you ask?[/QUOTE]

Last time I check air was considered a compressible fluid.
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