Dyna Beads how's it going !!!

[L J VFR]

 

[dgc67]

Number 12 shot is similar in diameter, but made of lead or steel, much cheaper.

but the weight sure aint the same as the ceramic beads.

And besides, It's much easier getting bird shot into a tire.. That whole putting ceramic pellets through a valve stem is taxing on an unpatient person like me..

I guess I was lucky, the 2 times I have used the dyna beads they went in super smooth and easy.

[lragan]

I did not order their installation kit, just the beads.  Used a squeeze bottle dispenser that honey came in, and a short length of flexible tubing left over from my air horn installation.  No sweat installing these little hummers.

As for weight of shot, maybe that is an issue -- for the same weight, one would not have nearly so many beads.

Allen I would like to participate in any order -- I could use 7 to 10 oz.

[silveradocowboy]

Definition of the $0.50 word of the day. And before anyone asks, yes I had to look it up, most of us rednecks don't keep words like that lying around. 

Main Entry: del·e·te·ri·ous
Pronunciation: \ˌde-lə-ˈtir-ē-əs\
Function: adjective
Etymology: Greek dēlētērios, from dēleisthai to hurt
Date: 1643
: harmful often in a subtle or unexpected way <deleterious effects> <deleterious to health>

synonyms see pernicious

— del·e·te·ri·ous·ly adverb

— del·e·te·ri·ous·ness noun

[dgc67]

Gee, Hoot, do you think there might be deleterious side effects to this injection method?

Now that the rest of us know what that word means, I would think the answer is "No".
The results might be unexpected from a naive soul, but I doubt they would be subtle by anyone's standards.   

[Greg Cothern]

Pardon me if this has already been mentioned, BUT.  What is the material that makes up the Dyna Beads?

I would be leery of lead shot deteriorating as it bounces around and etc against each other, and potentially creating a problem.

[roboto65]

They will go out. Tuesday Lawrence Thanks they should be here Monday

[L J VFR]

I balanced my front wheel with it on the bike with a spin-up wheel balancer.  We just jacked the front of the bike up.  This is the only TRUE way to balance a tire because you balance the whole wheel, tire, and axle with it on the bike. Many times you will take your car tires and have them balanced, and they take them off the vehicle and spin them up separetely.  Then you put them back on and it falls out of balance somewhere. This is due to the fact that spindles, axle shafts, etc are at play now.  I work sometimes on the weekend's with my brother and family who own and run Tontitown Frame and Axle.  You would be amazed at how many people put brand new tires on at Goodyear or ?? and leave and 15 minutes later call us for a wheel balance.  We spin up the tire and the right/left  fender shakes as if it is going to fall off. Once done, smooth as a kitten.  All my vehicles get their tires balanced this way. We have people stop in from all over the nation to get their tires balanced, especially semi trucks.  Been doing it for people since 1970.  Now we have seen many different brand of tires on many different vehicles, and for quality and trueness, it has always hands down been Michelin in our opinion. 
Sorry if I got of subject....

[lragan]

Pardon me if this has already been mentioned, BUT.  What is the material that makes up the Dyna Beads?

I would be leery of lead shot deteriorating as it bounces around and etc against each other, and potentially creating a problem.

The Dyna-beads are ceramic.  Perhaps this is the secret.  They neither compress nor corrode, although if dinged  hard enough, they will break.

[hootmon]

The Dyna-beads are ceramic.  Perhaps this is the secret.  They neither compress nor corrode, although if dinged  hard enough, they will break.

They are probably small enough and light enough to not do damage to the inside of the tire/wheel as well.. Just a thought..

[roboto65]

They have been in use for a while and I do not think they have caused any issues with tire wear inside.. I will putting them in the wifes truck and Gavins car and my Valk.

[lragan]

I would be leery of lead shot deteriorating as it bounces around and etc against each other, and potentially creating a problem.

This is a valid point, in my view.

I present the following theory on how these beads work.  Start with the beads just inserted, and the tire inflated.  I assume that most of the beads reside in the lowest part of the tire, as it sits on the ground, just due to gravity.  I say most of them because of electrostatic forces which come into play, which I will get to later.

As the tire begins to rotate, the beads must acquire kinetic energy from friction with the inside of the tire.  If the tire were frictionless (an impossible ideal for purposes of illustration), the beads would roll around and stay near the ground, responding only to gravity.  The inside of the tire is rough, however, especially from the point of view of the tiny bead.  Let's concentrate on a particular bead for a moment, and get back to the others later.  As our intrepid bead begins to sling around inside the tire, due to energy it has acquired from friction with the inside of the tire, the question becomes "where does it come to rest on the inside of the tire?".  Actually "rest" is a misnomer here as it is whirling around at the rate of rotation of the tire.

Assuming that the tire distends in the direction of the heaviest part of the tire/wheel/axle assembly, (A reasonable assumption, since the rubber is constrained but flexible.  The reason that a tire left unbalanced will get out of round.) then the tire takes on the shape of a cam, be it ever so slightly.  The first thought is obvious -- the bead will migrate to the portion of the tire furthest from the axle, as it is being constrained by the tire from flying off in a straight line.  I think this assumption is incorrect, because of energy considerations.  The kinetic energy of the bead is related to its mass and the square of its velocity.  The velocity of a point on the inside of the tire is proportional to its distance from the center of the axle, so to settle in the "bulge" of the tire requires the bead to acquire more energy than to settle closest to the axle. 

Our little bead is a good deal like me, in that it will settle in the position that requires the least energy.  This occurs only because it is free to move on the inside of the tire.  So, it tends to the point furthest from the "bulge", thus contributing to balancing the structure. 

That it is made of ceramic causes it to acquire electrostatic energy as well.  For those of you who still have hair, you have seen, when you comb it in a very dry environment, how the hair is attracted to the comb after a few strokes.  This is because the comb becomes charged, due to friction with your hair, with the opposite charge from that which remains in your hair.  I have observed this electrostatic effect in the beads in a plastic bottle, or even in the plastic bag they were shipped in.  Since all the beads have a like charge, and like charges repel, they tend to avoid one another.  This keeps them from "clumping" together in the lowest energy part of the tire, unlike, say steel or lead shot.  It also causes them to cling to the inside surface of the tire, which carries the opposite charge.  The charge they can carry, and therefore the electrostatic force exerted on them, will be roughly independent of the size of the bead, so the small size causes them to cling tighter to the inside of the tire than a larger bead would.

Someone has speculated that the beads fall to the bottom of the tire when you stop.  They may, but I think it may take awhile.  No insulator is perfect, and the charge will leak off over time.  So if the tire sits there long enough, they should fall to the bottom.  I just don't know how long this may take.  In a plastic drink bottle, they cling to the sides for days, at least. 

Anyway, that's my theory, and I am sticking to it, at least until someone can point out the error of it.

[Charles S Otwell]

Anyway, that's my theory, and I am sticking to it, at least until someone can point out the error of it.

Not pointing out any errors in your theory, heavens knows I would never challenge an engineer , So this is just a question for my clarity. If the tire being distended because the extra weight, causing it to become out of round and this causing the vibration, then how does a lead weight attached to the wheel keep the rubber from distending and becoming out of round which would still cause a vibration. If it could why wouldn't a wheel weight correct an out of round tire, which it won't. I was under the assumption that the vibration came from an unequal pull from the center of what ever was rotating, disrupting the harmony. Hence the need for a harmonic balancer on a crankshaft. Or weights on a flywheel, or drive shaft etc.. I realize I'm setting myself up for a thrashing, but oh well, it won't be the first time

[lragan]

I didn't make this point very clear as to what is cause and what is effect.  If the system is out of balance for any reason, the tire will be distended.  If the axle were perfectly fixed and immovable this would not happen unless the imbalance was due to the tire alone, but this is not the case, because of springs and, even if there were no springs, the finite weight of the vehicle.  The distension of the tire is due to the imbalance in the system, and variations in the tire weight may not even be the principal cause.  Nonetheless, the tire will distend in the direction of the heavier portion of the whole system -- tire, wheel, brake rotor or drum -- whatever turns can add to the imbalance.

I think Lance's point is that modern tires are pretty well balanced from the get-go, and imbalance in the rest of the system can be quite significant.  I might venture a guess that the cast aluminum wheels on our bikes are better balanced than the stamped steel ones on most automobiles, but I have no facts to back up this conjecture.

It seems intuitive to me that the optimum approach would be to dynamic balance the entire system, sans tire, with weights, then mount the tire and insert beads.  This way the beads are only compensating for the sins of the tire, and not having to act on the tire to correct imbalance in the non-tire components.

Someone stated that the beads would not work on a "wide" tire.  I can see where, if the tire is wide enough, there may be lateral variations that cause a more complex vibration/shimmy.  This one makes my head hurt, and I don't intend to try to deal with it...

[Charles S Otwell]

If the axle were perfectly fixed and immovable this would not happen unless the imbalance was due to the tire alone, but this is not the case, because of springs and, even if there were no springs, the finite weight of the vehicle.

IF this is the case how can a perfectly fixed and immoovable spin balancer compensate for these other variables?