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 08-28-2013, 07:29 AM #76 gravityisnotmyfriend Beastly Adventurer     Joined: Jun 2012 Location: ((kg*m)/s^2), IA, USA Oddometer: 1,649 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.
08-28-2013, 08:29 AM   #77
SgtDuster

Joined: Feb 2010
Oddometer: 3,458
Quote:
 Originally Posted by gravityisnotmyfriend 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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2010 Buell Ulysses
1984 Suzuki GR650 "Tempter"

SgtDuster screwed with this post 08-28-2013 at 08:38 AM

 08-28-2013, 09:32 AM #78 gravityisnotmyfriend Beastly Adventurer     Joined: Jun 2012 Location: ((kg*m)/s^2), IA, USA Oddometer: 1,649 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.
 08-28-2013, 11:32 AM #79 Borghi Adventurer   Joined: Mar 2009 Location: Ithaca NY Oddometer: 31 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.
 08-28-2013, 01:03 PM #81 SgtDuster Beastly Adventurer     Joined: Feb 2010 Oddometer: 3,458 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. __________________ 2010 Buell Ulysses 1984 Suzuki GR650 "Tempter" SgtDuster screwed with this post 08-28-2013 at 05:59 PM
08-29-2013, 05:31 PM   #82
'05Train
Mind is not for rent

Joined: Jun 2011
Location: Maryland
Oddometer: 1,086
Quote:
 Originally Posted by El Gato 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.

Sent from my iPad, probably while I'm pooping.
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08-29-2013, 06:50 PM   #83
Yossarian™
Deputy Cultural Attaché

Joined: Jul 2007
Location: the 'Ha
Oddometer: 9,713
Quote:
 Originally Posted by '05Train 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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 08-29-2013, 07:38 PM #84 hugemoth Beastly Adventurer     Joined: Sep 2007 Location: In the TARDIS Oddometer: 3,071 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?
08-29-2013, 08:26 PM   #85
gravityisnotmyfriend

Joined: Jun 2012
Location: ((kg*m)/s^2), IA, USA
Oddometer: 1,649
Quote:
 Originally Posted by SgtDuster 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?

10-12-2013, 08:13 PM   #86
ben2go
Moto Flunky

Joined: Jun 2011
Location: Upstate SC USA
Oddometer: 3,850
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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 11-27-2013, 12:57 PM #88 MrPulldown Beastly Adventurer     Joined: Aug 2009 Location: Truckee Oddometer: 3,536 [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. __________________ 94 DR 350 SE LED Turn Signals, Flasher Relays, and Diode Kits for SALE

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