1. I really don't understand what all the discussion is about. They don't fix anything and they make tire balancing harder. What is there to discuss?

When I get tires put on they balance them and I ride, no more balancing till my next set. Whether I ride motocross, do wheelies, or jumps the grand canyon the wheels are always balanced. You can run the argument of "what if you throw a weight?". I carry a few stick on weights in my bag for that very reason. If one flies I stick another in it's place, done. It's never happened to me...ever.

With the beeds your always in a perpetual state of balance and unbalance. Every time you stop your wheels lose balance. Every time you hit a significant bump you lose balance. If you change tires you have to mess with beed swapping. If you let air out of your tire you can get beeds stuck in your stem.
All for what? a tire thats only balanced when your cruising and requires more work.

These are good for semi trucks and large vehicles that are a pita PITA to balance.

2. Originally Posted by piperjim
It's surprising to me that the company that manufactures Dyna Beads hasn't commissioned a non-biased, i.e. university, research study to determine the efficacy of Dyna Beads.
The cynic in me can think of a very good reason.

3. Originally Posted by PGlaves
but I am trying to understand how they would work, assuming that they do.
In a spinning tire any beads will, due to centripetal force, be spread out around the inner circumference of the tire. Assuming a round tire with no low spots where the beads could accumulate the location of the beads will be somewhat random. Next assume (there's a lot of assumptions going on here ) that the tire and/or wheel is out of balance enough to cause a reaction against the sprung suspension. [If there is no sprung suspension the beads will do nothing.] As the tire goes around the heavy spot will cause the suspension to compress. In an extreme case the out of balance wheel/tire could lift the tire from the road.

So you've got beads plastered against the inner circumference of the tire, the tire connected to the wheel, and the wheel moving up and down with the suspension. As the heavy spot aligns with the forks the wheel tends to hop up. At that instant the beads in contact with the upper circumference will not follow the new path of the wheel, but instead will tend to continue at a tangent. Thus, for a short while, the beads at the top of the tire will not be in contact with the tire. The beads at the bottom will. This temporarily changes the mass of the tire/wheel and, in theory, tends to counteract the out of balance effect on the suspension. I'd guess the effect would follow the sine function with maximum force/change of mass as the heavy spot is in alignment with the forks. That is only a guess.

Or something like that.

The parts I don't get... what happens during velocity changes? Will an out of balance wheel alway wind up in harmony with the suspension... after how long? What effect, if any, will a deformed tire due to rough road conditions have? What effect will suspension damping have? Etc.

They may work at a constant velocity on a smooth road.

4. this is all very interesting. i find it odd that people get such varying experience with the Beads...
can someone explain the Static Balancing process for me please? is that on a stand with the tire held vertically?

5. Put an axle through the wheel. In the case of the rear wheel on a modern BMW you need an adapter so the axle is centered. Both ends of the axle fit in bearings. Suspend the bearings far enough off the ground so the wheel spins freely. Let the wheel go and the heavy spot will sink to the bottom. Rotate the wheel about 1/4 turn and watch the heavy spot sink to the bottom again.

Here I am checking the wheel sans tire using the Marc Parnes balancer and an older version of his rear wheel adapter. Some tires come with a colored dot which marks the light spot on the tire. You match that with the heavy spot on the wheel which is assumed to be the valve stem. Notice where the valve stem is in this picture.

On this wheel the valve stem is the light spot. Interesting. But then these days fewer and fewer tires are marked with the dot so the actual location of the wheel heavy spot isn't so important, I guess.

Balance is done by adding weight to the light spot (the top when the wheel stops). When you've got the right amount the wheel will stop in random spots when given a gentle spin. The balancer is good enough in practice that you will not find the PERFECT amount of weight. You'll get it to where adding or removing 5 grams is enough to move the heavy point from one location on the wheel to another. That is plenty close enough.

6. Originally Posted by leesrt
I really don't understand what all the discussion is about. They don't fix anything and they make tire balancing harder. What is there to discuss?

When I get tires put on they balance them and I ride, no more balancing till my next set. Whether I ride motocross, do wheelies, or jumps the grand canyon the wheels are always balanced. You can run the argument of "what if you throw a weight?". I carry a few stick on weights in my bag for that very reason. If one flies I stick another in it's place, done. It's never happened to me...ever.

With the beeds your always in a perpetual state of balance and unbalance. Every time you stop your wheels lose balance. Every time you hit a significant bump you lose balance. If you change tires you have to mess with beed swapping. If you let air out of your tire you can get beeds stuck in your stem.
All for what? a tire thats only balanced when your cruising and requires more work.

These are good for semi trucks and large vehicles that are a pita PITA to balance.
I'll take a shot at your statement that your "tires stay in balance", sorry to inform you that maybe they suit you the whole time they're on the bike, but they wear unevenly & thus are not in balance with the same weights in place.A tire thats balanced "while I'm crusing is the reason I balance it in the 1st place!? Carrying weights to stick back on-I have a hard enough time remembering where I've been , let alone how much weights on the wheels of various vehicles-get real-do you have a "wheel weight log"? As to being hard to install, beads are very easy and besides you are paying someone else to do it anyway so what's the point there? Yes they work in big truck tires. Going on, as stated there are bead threads that extend to many posts elsewhere and go all over.
I love bead threads for the "smoke & mirrors aspect they offer" which is hard to come by in an oil thread!

7. Originally Posted by marchyman
But then these days fewer and fewer tires are marked with the dot so the actual location of the wheel heavy spot isn't so important, I guess.
Your wheel is more likely to be out of balance than your tire. I haven't bothered balancing the rear wheel/tire for the last couple of years. No vibration issues. I do balance the front, but could prolly get away without doing it.

8. Originally Posted by kantuckid
I'll take a shot at your statement that your "tires stay in balance", sorry to inform you that maybe they suit you the whole time they're on the bike, but they wear unevenly & thus are not in balance with the same weights in place.A tire thats balanced "while I'm crusing is the reason I balance it in the 1st place!? Carrying weights to stick back on-I have a hard enough time remembering where I've been , let alone how much weights on the wheels of various vehicles-get real-do you have a "wheel weight log"? As to being hard to install, beads are very easy and besides you are paying someone else to do it anyway so what's the point there? Yes they work in big truck tires. Going on, as stated there are bead threads that extend to many posts elsewhere and go all over.
I love bead threads for the "smoke & mirrors aspect they offer" which is hard to come by in an oil thread!
All you have to do is look at the size weight that on there and keep an extra couple. If one gets thrown it's pretty easy to see where it was by the little square ouline with nothing in the middle.

Whether they use lead weights or weights made out of goat cheese they still do the same thing.

9. Originally Posted by martinPH
yeah i saw that video once before, on the Dyna Beads website, after i heard about them from a buddy of mine. it's relatively easy to understand how -and i mean without knowing the actual physics of the matter- centrifugal forces and the dynamics of wheel/tire mass etc., will allow the beads to re-assemble themselves with each start/stop.

for me, here's the thing:
quite obviously, the old way works well- it's a time tested reality. also, it stands to reason that modern tires no longer require as much offset in added weights to achieve balance as they once did. the fact that several folks have stated they got better overall wear out of their tires with the beads is enough for me- i, too, have experienced scalloping or uneven tire wear over the years on different bikes.
not being an engineer or physicist, this very concept FEELS sensible to me. OK, it's NOT our granddaddy's tire balancing method.... but for the most part, we aren't riding our granddaddy's bikes either.

i likes to take advantage of new technologies, and i know many of you guys do, too- tell me you don't have a big fat GPS/Sat NAV or a Blackberry or iPhone? why not employ any and every tool available to us?

i'm goin for it.

i don't ride as much as some of you guys, AND i have 5 bikes, so my year's mileage totals are spread out between at least two of them, or more in any given year, with the bulk of my riding spread out between the two BMWs. why wouldn't i try the beads in one out of 5?

i'll mention to the shop guys i want them to install Dyna Beads in the new tires on the K100. it'll be interesting to see if this sparks comment or debate from them!

10. Originally Posted by martinPH
That is one of the infamous videos.

Here is the other.
This one is much more compelling because of the strobe stop action. As well, note this is a different company using the same principle in a different way.

IMO these 2 videos together should be enough to convince anyone of the physics involved.

That is one of the infamous videos.

Here is the other.
This one is much more compelling because of the strobe stop action. As well, note this is a different company using the same principle in a different way.

IMO these 2 videos together should be enough to convince anyone of the physics involved.

Thanks Mike! That is interesting, I hadn't seen that one before.

12. I'd like to see Mythbusters take this on one. They do some stupid stuff lately, and this one is a good one.

13. Originally Posted by marchyman
Put an axle through the wheel. In the case of the rear wheel on a modern BMW you need an adapter so the axle is centered. Both ends of the axle fit in bearings. Suspend the bearings far enough off the ground so the wheel spins freely. Let the wheel go and the heavy spot will sink to the bottom. Rotate the wheel about 1/4 turn and watch the heavy spot sink to the bottom again.

Here I am checking the wheel sans tire using the Marc Parnes balancer and an older version of his rear wheel adapter. Some tires come with a colored dot which marks the light spot on the tire. You match that with the heavy spot on the wheel which is assumed to be the valve stem. Notice where the valve stem is in this picture.

On this wheel the valve stem is the light spot. Interesting. But then these days fewer and fewer tires are marked with the dot so the actual location of the wheel heavy spot isn't so important, I guess.

Balance is done by adding weight to the light spot (the top when the wheel stops). When you've got the right amount the wheel will stop in random spots when given a gentle spin. The balancer is good enough in practice that you will not find the PERFECT amount of weight. You'll get it to where adding or removing 5 grams is enough to move the heavy point from one location on the wheel to another. That is plenty close enough.
I'll add that my balancer easily detects two grams of weight. If you are really patient, it will pick up 1 gram, but that level of accuracy is not needed.

Also, it is reproducible which is important. You always want to double check for reproducibility by removing the balancer setup, putting it back on in a different orientation, and confirming no change. I find the static balancer is excellent, easier than the beads that I no longer use, and more satisfying to perform.

I also confirm the light spot, and it is always NEAR, but not really AT, the valve stem.

Marchy, I've heard about guys lightly grinding away at the rim to produce a perfectly balanced wheel with no tire. Seems a bit obsessive/compulsive to me. Have you ever calculated how many grams out of balance your bare wheel is? I keep meaning to do that, but never get around to it.

14. ## Just try it???

I know that there must be someone that would like to experiment. Who cares about theory?

Force a tire and wheel out of balance with weights, ride it and note the condition. Add beads to the unbalanced wheel and ride it again. Did it correct the out of balance condition or not?

That being said, it needs to be somewhat reasonable test. By that that I mean you can't throw a wheel out of balance by 6 oz and expect 3 oz of beads to fix it.

I would think that someone could have feedback on this by the end of the day and finally put this issue to bed!

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