tire balancing weights

[Theo]

In regard to Dyna Beads, there was a letter in the February 2010 Motorcycle Consumer News asking about Dyna Beads. MCN's response was that they tested the beads in October 2006. While they didn't reprint the entire review they did offer a summary:

'....we tested them on a Honda 599. Using a shop's spin balancer, we checked the bike's rear wheel, which had 1.6 oz. of balance weights in place. The balancer agreed with the amount and location of the weights. After installing the specified two ounces of beads in the rear tire and removing the rim weights, the balancer found an out of balance condition. This test was repeated five times and the balancer continued to call for the replacement of the 1.6 oz. of rim weights in the same location. Over-the-road testing was next. Without the rim weights, the rear wheel produced noticeable vibration and the installation of the beads gave a barely perceptible improvement. Also, the weight of the beads added so close to the tire tread gave a noticeable increase in gyro stability, making the steering heavier. We also tried them on a car and were disappointed. Bottom line: save your money for a proper spin balance.'

Keep in mind that MCN is entirely subscriber funded, they do not take advertiser's dollars so it is arguably the most unbiased motorcycle magazine available.

Their conclusion seems to make sense. The beads are forced to the outer diameter of the tire by centrifugal force so the speed at which the tire is rotating dictates the distribution of the beads. If the tire is rotating at a fixed speed the beads will be evenly distributed around the tire and theoretically have no effect on the balance of the tire/wheel. The only situation where I could see the beads actually affecting balance would be if there was a defect in the tire and the inner diameter was inconsistent. Beads would be concentrated in the area where the diameter was largest as the larger diameter would cause the centrifugal force to be higher at that point.

Thanks,
Joe

Well that may all be well and true, but one thing bothers me about that test. On their website and everywhere you look, they have a big disclaimer "Not for car tires". Why would they even bother testing this. Excerpted from their site:

We don't market to cars, SUV's or minivans due to the overall style of those tires, which are low and wide. This style of tire commonly exhibits varying degrees of lateral imbalance due primarily to the width. This type of inbalance can only be corrected with carefully placed wheel weights. So that means that while Dyna Beads should not be used as the sole balancing method for these tire types, they can be used as a supplemental method.
Using a combination of weights and Dyna Beads results in higher tire mileage and a reduction, or elimination, of future rebalancing requiements.

But back to motorcycle tires. Like I said before, I have had them installed for 5000 miles and have not noticed any of the effects they mentioned. No vibrations, and no sluggish steering. Also, maybe if the tire was truly round and balanced, then yes, when spinning at speed the beads would be evenly distributed. Otherwise in an out of balance tire, the beads would be doing their thing. Anyways, I don't want this to turn into an oil thread so that's all I have to say.

[Joe Nardy]

Also, maybe if the tire was truly round and balanced, then yes, when spinning at speed the beads would be evenly distributed. Otherwise in an out of balance tire, the beads would be doing their thing. Anyways, I don't want this to turn into an oil thread so that's all I have to say.

I don't want it to turn into an oil thread either but I'd like to be able to understand the science behind the beads.

I think the question here is: What determines the distribution of the beads?

A. Speed of rotation
B. Roundness of tire (diameter)
C. Weight distribution of wheel/tire (balance)

I would think A and B. However, I m not a physicist so I'd appreciate input from others with more knowledge.

Thanks,
Joe

[Nessism]

In regard to Dyna Beads, there was a letter in the February 2010 Motorcycle Consumer News asking about Dyna Beads. MCN's response was that they tested the beads in October 2006. While they didn't reprint the entire review they did offer a summary:

'....we tested them on a Honda 599. Using a shop's spin balancer, we checked the bike's rear wheel, which had 1.6 oz. of balance weights in place. The balancer agreed with the amount and location of the weights. After installing the specified two ounces of beads in the rear tire and removing the rim weights, the balancer found an out of balance condition. This test was repeated five times and the balancer continued to call for the replacement of the 1.6 oz. of rim weights in the same location. Over-the-road testing was next. Without the rim weights, the rear wheel produced noticeable vibration and the installation of the beads gave a barely perceptible improvement. Also, the weight of the beads added so close to the tire tread gave a noticeable increase in gyro stability, making the steering heavier. We also tried them on a car and were disappointed. Bottom line: save your money for a proper spin balance.'

Keep in mind that MCN is entirely subscriber funded, they do not take advertiser's dollars so it is arguably the most unbiased motorcycle magazine available.

Their conclusion seems to make sense. The beads are forced to the outer diameter of the tire by centrifugal force so the speed at which the tire is rotating dictates the distribution of the beads. If the tire is rotating at a fixed speed the beads will be evenly distributed around the tire and theoretically have no effect on the balance of the tire/wheel. The only situation where I could see the beads actually affecting balance would be if there was a defect in the tire and the inner diameter was inconsistent. Beads would be concentrated in the area where the diameter was largest as the larger diameter would cause the centrifugal force to be higher at that point.

Thanks,
Joe

Interesting read Joe. Thanks for sharing.

[Theo]

I don't want it to turn into an oil thread either but I'd like to be able to understand the science behind the beads.

I think the question here is: What determines the distribution of the beads?

A. Speed of rotation
B. Roundness of tire (diameter)
C. Weight distribution of wheel/tire (balance)

I would think A and B. However, I m not a physicist so I'd appreciate input from others with more knowledge.

Thanks,
Joe

I'm no physicist either so I can't really offer anything intelligent. The best I can do is give link to the dyna bead site explaining how it works.
http://www.innovativebalancing.com/HowItWorks.htm. To me from that link, it seems like it's more of A and C that have an affect on the balance of the tire.

[Nessism]

I'm no physicist either so I can't really offer anything intelligent. The best I can do is give link to the dyna bead site explaining how it works.
http://www.innovativebalancing.com/HowItWorks.htm. To me from that link, it seems like it's more of A and C that have an affect on the balance of the tire.

According to this link the beads move in the direction of motion which makes sense, however I don't see how they can move fast enough to counteract the vibration in real time. I'll stick with cheap and effective balance weights.

[dpep]

For my 1100E I had the beads put in the last set of tires I got. I do not like the ride on my bike now, but it could be something other than the beads. I don't have near the miles to compare on the E that I do on my other bikes, and it is the first time I have tried this tire brand (Cheng-Shin Hi Max). It certainly feels like they might be out of balance. I am going to dump the beads and balance with weights to get a direct comparison.

Are the beads used in professional racing? That is usually a pretty good indicator of efficacy.

[Theo]

Are the beads used in professional racing? That is usually a pretty good indicator of efficacy.

That got my curious so I looked it up. Apparently they can not be used in racing tires.

Can I use Dyna Beads for motorcycle road racing?
No. The inner liner compound of motorcycle road racing tires is too soft to allow Dyna Beads to perform properly. (this does not apply to off-road motorcycle racing)

[bakalorz]

According to this link the beads move in the direction of motion which makes sense, however I don't see how they can move fast enough to counteract the vibration in real time. I'll stick with cheap and effective balance weights.

Let me first off say that I have not yet used their or other beads yet
(although I intend to try them at some point)

Their description could be clearer ...
Let me try to describe it better.

First of all, the best way to think of the beads is that they are a bunch of little balance weights that AUTOMAGICALLY move to the correct spot to balance the tire each time it starts to spin. The force that makes the tiny weights move to the right spot is the vibration of the imbalance itself. Their drawings try to describe the way the process works.

But, before we begin, a couple of assumptions that need to be spelled out
1) the inner surface of the tire is perfectly concentric to the axle
2) the inner surface of the tire is smooth enough that the beads can move relatively freely
3) that there is "more than enough" weight of beads installed

For the first drawing, we look at the tire sitting there not spinning.
All the beads are on the bottom.

For the second drawing, assume a perfectly balanced tire begining to spin.
Basically the beads spread around all around the tire and are evenly distributed. Once they are distributed, each bead basically stays in one spot on the tire as the tire goes around. (i.e. the beads are going around with the tire) ... It's like a tire with a whole bunch of tiny balance weights evenly spaced all around it.

For the third drawing, assume the same situation as the second, but add a heavy spot in the tire. As the heavy spot goes over the top, the tire "HOP"s up just a little bit (say 1/16 of an inch). The beads were originally evenly distributed around the tire (and spinning with it, not moving relative to the tire). As the tire hops up, inertia of the beads resists the hop, so the beads move 1/16 of an inch in the direction opposite the heavy spot and then continue to stay in the same (new) spot on the tire as it goes round. After a few hops, the distribution has changed to look like figure 3
and the tire is less out of balance ... The whole bunch of tiny balance weights are no longer evenly spaced on the tire, but are crawling around inside the tire to fix the balance.

For the fourth drawing, they are trying to show that as long as the tire has a little bit of remaining unbalance, the beads get a force that moves them to fix the unbalance ... the tiny weights keep crawling as long as there is imbalance

until in the fifth drawing the tire is balanced and all the beads stay in place on the tire as it rotates around ... all the tiny weights have reached their final position.

----

So thats how it works in theory anyways.
Does it work in real life too ?
It should; but, well remember those assumptions above ... If any of them are violated, then it won't work right.

If you don't have enough balls, they will all move to the opposite side, but still won't be heavy enough to offset the imbalance ... and I suspect that you need some excess just to have some distributed around the tire.

If the balls can't move around easily enough then they may never reach the spots that they need to. This point makes me wonder about the tire balance machine and if the balls can properly balance a tire in it. The machine may be too smooth, and some vibration probably helps the balls move around in the tire. Also, the suspension on a motorcycle lets the tire hop a little, the axle on the balance machine may hold the tire to rigidly for the tire motion to move the balls where they need to go. And finally, a tire on the road has the contact patch, where the tire flexes inward relative to its "neutral" position, which I'm sure helps the balls move around.

But the big thing that may cause problems is if the inside of the tire is not concentric enough to the axle. A thin spot could collect all the balls, even though it may not be opposite the heavy spot of the tire (that said, a thin spot IS pretty likely to be the light area on the tire and where the balls SHOULD collect anyway ... but its not guaranteed to be the right spot)

I also found the MCN article a little suspect based on this sentence
Also, the weight of the beads added so close to the tire tread gave a noticeable increase in gyro stability, making the steering heavier
NUH UH, I don't think so ... 2 ounces of balls makes the steering heavier, but 1.6 ounces of lead an inch or two further in doesn't? (To say nothing of the several pounds of tire)


The two biggest selling points for the tire balls to me are:
1) Less work balancing (and you can't get it wrong by accident)
2) As the tire wears, the balance will change, and should be rebalanced every once in a while, with the balls you don't have to.


Well, that was way more than I expected to write at first.

[SqDancerLynn1]

More snake oil ! has anyone tried balancing the rim seperatly and putting the weights on the inside, then mounting the tire?

[almarconi]

According to this link the beads move in the direction of motion which makes sense, however I don't see how they can move fast enough to counteract the vibration in real time. I'll stick with cheap and effective balance weights.

Before condemning them, why don't you give them a try? They really do work quite well.

[lurch12_2000]

Before condemning them, why don't you give them a try? They really do work quite well.

As a point of comparison:
With clip ons, I usually see 10, 20 , and 30g weights. With stick on, 7 and 14g weights. With beads, what is the equivalent number of beads to use? ...or is just a package of 20? 30?... that supposedly covers any out of balance condition?
I've had to use up to 84g of weights to balance out some of these old rims and/or new tires.
Another question:
If the bike sits for a few months and there's some moisture inside (usually) the tire, are they coated metal, or non-rusting metal, or prone to rust and clumping together possibly negating any usefulness?

EDIT:
This may answer some of my questions, specifically with Dyna-Bead brand:

http://www.dynabeads.ca/chart.htm#MotorcycleChart

ceramic not metal

2-3oz depending on bike tire size (56g-84g)

if the basic theory works, then a plus is the dynamic balancing over the life of the tire

NOTE: check out the website's link for the installation tutorial...maybe a new use for a vibrator?

[lurch12_2000]

I am going to dump the beads and balance with weights to get a direct comparison.

Do you mount your own tires? I assume from the year of your 1100E, it uses the tubeless rim, so you would break the tire bead, pop one side off from the top as usual, and then scoop or shop vac out the beads?...then pop that side back on before inflating? ...since you'll still be using the same tire.
I wonder what the guys who do this for a living think about beads?...hassle or no? Any opinions, besides us who change a few tires a year out? I'm no expert since I've only changed about 10 bike tires myself in the last 2-3 yrs on my collection of GSes.

[Theo]

NOTE: check out the website's link for the installation tutorial...maybe a new use for a vibrator?

Haha yeah. I just ended up using my electric shaver and it all worked out. But it still does go pretty slow. You have to pour them in real slowly.

[Ohioan]

Use stick on weights.

Give the clip-ons to someone who molds their own bullets.. like me

[Dogma]

Chiming in on the beads: I have them in my 850. Tube in the rear, tubeless up front. They do work. I've had them up to near triple digits. I rode with them at Brown County and WV last season. Probably equal fuss to installing weights, but you don't need extra apparatus. Maybe a little more fuss, if you're experienced at balancing.

They do their thing when the wheel is still turning slowly. At the slow speeds, you can't feel the wheels out of balance, but it's enough shake to get the beads to where they need to be. Motorcycle Consumer News should have known not to put them on a static balancer. They won't work if the axle is held rigid. They should have known not to put them on a car. They add only slightly more centrifugal inertia to a wheel than static weights. If they really can feel more centrifugal force from a couple ounces added to a 15 lb wheel, then I'm impressed. As far as I'm concerned, MCN failed to do any homework before doing their testing. I'll have to remember to discount anything they say.

All that said, there is one significant shortcoming. Hard bumps at highway speed can upset the beads. At those speeds, they have a hard time redistributing themselves, and you'll get a noticeable shake for a while or until you slow down. Not necessarily a dangerous shake, but definitely adds to the irritation of really bad pavement on the slab.

After trying them out for a while, I'm thinking I may not use them again. There is a section of interstate near here that can upset them reliably. On the other hand, that particular stretch of pseudo-pavement might knock a sticky weight off. If I was paying someone else to mount my wheels, I might want weights, preferably not sticky. Doing it myself again... I might re-use them for being to lazy too build a balancing rig.

Bottom line, they do work. Would I recommend them? Eh. Make up your own mind.