Dynabeads - Anyone use them?

[duc_fan]

well if you want to split hairs, centrifugal force isnt  really a force.

+1

"Centrifugal force" is an imaginary force (to be fair... it does show up in the math sometimes, but only if you're using a rotating frame of reference).

Centripetal force is the force required to make the path of an object curve (and, say, travel in a circle).  What you have are the inertia of the object in motion, which wants to make it travel in a straight line, and you have centripetal force which pulls it into a curved path.

So, what holds the beads in place is friction, and friction needs a "normal" force (no force, no friction)... the normal force in this case is the centripetal force applied by the tire carcass constraining the beads to a fixed distance from the point of rotation.

Science is fun... but I'm still wondering if anyone uses a dynamic balancing agent like Dynabeads on their Ducati. 

[pennyrobber]

well if you want to split hairs, centrifugal force isnt  really a force.

That's why I said acceleration. I know someone would bring it up.

[He Man]

That's why I said acceleration. I know someone would bring it up.

Hey, christian wanted to split the hairs. 

In newtonian terms, no acceleration = no force!

unless we start having beads that use nuclear force to adhere to the surface of the tire!

[scott_araujo]

Ok, so looks like it does work.  Like many things in physics it's the opposite of my first instinct.  Looks like something useful for wheels that might pick up mud/dirt/ice but I don't need none for my moto thanks.

Scott

[He Man]

Ok, so looks like it does work.  Like many things in physics it's the opposite of my first instinct.  Looks like something useful for wheels that might pick up mud/dirt/ice but I don't need none for my moto thanks.

Scott

i woudnt say that yet. like all "demonstrations" this one isnt even close to the actual product.

that wheel is HORRIBLY off balance, and those are metal bearings taht are sliding around perfectly in a fluid.

While in real life, the beads are catching on the walls of the tire and just flopping around wherever they please. unti lthere is enough force to pin them to the wall (which really is probably anything over 10mph or something.

So you wonder why they didnt use real dynabeads in that video instead of an example of how it works.

[errazor]

If you look closely at the bolt below the wheel it seems that it is more vibration with the balance ring.

[suzyj]

That video is awesome. I love science. So it looks like these would actually work. Although I wonder about low speeds - it seems like without the magnet, the wheel in the video shuddered more with the balancer on it until it got up to speed than without the balancer.

Still - very interesting stuff!

I think there's a big difference between steady-state speed and the dynamic case, where the wheel is accellerating/decellerating, and the road is flexing the tyre carcass.  I'd imagine the balls would just bounce around.

[Blue]

Hello Everyone,
<nervous glance around the room>
I am a Ducati owner and I have purchased and used the Dyna Beads.
The bad news:
I have never used the beads to balance my Ducati's tires.  The last time I had a shop mount and balance the tires, they only put 1/4 of an ounce of weight for each rim.  No point in spending the money to have them do it and no point in putting the beads in to balance that out.  The tires wear evenly and do not vibrate or shake going down the road.
The good news:
I have used these bead in my other motorcycles and truck tires. 
I have used them in the front tire of one of my other bikes (a cafed out KZ running a bias ply 100/90-19).  When I bought it, it had two ounces of weight on the front rim.  It felt lumpy going down the road with the weight, it felt lumpy going down the road without the weight, it felt smooth with 1 ounce of the beads.  I was happy!  Of course, this was only at highway speeds as below 35mph, I couldn't feel any vibration.
I have also used the beads in my truck's tires.  The weights on my rear tires got thrown off in some spirited off road driving resulting in a vibration on the highway and interstate.  I added 2 ounces of the beads to the tires that had lost their weights and the ride smoothed out.  In fact, the ride was better than before.  So, I pried off the other weights on the other rims and added the beads.  The ride was nicer with the beads then before when the tires were balanced with the weights. 
This has been my experience.
I would not tell anyone to go out and buy these or pronounce them to be the Holy Grail of balancing.  I just haven't had a bad experience with them yet. 
I also feel that the whoever balance the tires on my truck and motorcycle before I bought them did a poor job.  The beads may work as well as balancing with lead weights.

[Desmo Demon]

Anyone use these?

All I can say if that my wife's R1 developed a nasty front end vibration/wiggle that was so bad in mid curve that she felt the bike would go into a tank slapper. It was bad enough that she almost was going to quit riding that bike. I tried and tried to get the vibration out. I checked the steering stem bearings and they seemed fine. I static balanced and rebalanced the front wheel several times. I used two completely different front wheel and rotor combinations. After two or three tires and alternating the wheels/rotors, I finally put some of the Dynabeads in the front wheel at the recommendation of a riding buddy of ours, and......the vibration disappeared. The vibration has been gone for about 30k miles, using both of the front rims and rotors, and running several different tires (10+). She also says the bike is smooth as glass up to 165 mph (indicated). She's sold on the Dynabeads, and we run them in every tire mounted on her R1. Interestingly, though, we do not use them on any other bike.

For other tidbit of info....I do not balance my tires any more. Other than the tires on the R1, the other bikes only get the tires mounted and then we ride them. I have not noticed any vibration or concerns with non-balanced tires on any of the bikes, and my 748 has been a hair north of an indicated 150 mph without any vibration. Also, I have not seen anything that I would indicate an increase in tire mileage with the Dynabeads, and we've gone through over 80 tires in the last four years.

[Amlethae]

So is this *the answer* to getting rid of those ugly dirt-collecting rim weights?  Seems simple enough to install without having to remount the tires (except for the 90deg bend in the front tire stem). 

Thoughts? 

[scott_araujo]

i woudnt say that yet. like all "demonstrations" this one isnt even close to the actual product.

But I expected it not to work at all.  It seems it's definitely worth a second look.

Scott

[mitt]

seems like good experiences so far on problematic wheels, but also not many of us have problem wheels.


mitt

[scott_araujo]

I'm still skeptical but I do remember these from when I was a kid.  Kinda the same thing and I really liked these:
http://ijustwantaneasylife.blogspot.com/2006/07/spokey-dokes.html

Scott

[duc_fan]

Thanks for sharing!

From what I have gathered (here and elsewhere):

1) Most modern motorcycle tires are very well made, and often don't require balancing.

2) More often than not, the wheel is more out-of-balance than the tire.

3) Numerous riders change their own tires w/o rebalancing and have no problems.

4) Many other riders change their own tires and do a simple static balancing with no problems.

5) Dynabeads are unnecessary in most cases... but for problem wheels/tires they can do the trick.  They are great for steady-state or nearly steady-state conditions (i.e. freeway or highway with moderate accel/braking), but probably not great for the very hard accelerations and decelerations experienced at the track.  Hence why they and similar products are very popular with the trucking industry.

This is just what I, personally, have come away with from my web searching and question asking.  I don't have any problems with out-of-balance moto tires right now, so I see no reason to spend money on them.  Actually, the greatest thing I've come away with is realising how many riders do their own tires changes!  This could save me a bit of money, and I'm always down for that. 

[Duck-Stew]

Also looks like this is a fool proof design with merit!