Dyna-Beads for Balancing Tires?

[Dan Filetti]

Anyone ever use the Dyna-Beads for balancing their tires as apposed to traditional wheel weights?  A buddy of mine is trying to talk me into them.  I've done some forum searching on BMW lists etc. and seems there a decent number of folks that like them.  Most of the folks that come out against them seem to have never actually try them.  One guy said he'd felt a vibration north of 100MPH but only a slight one.

I'd appreciate any input any of you had.

Dan

[rktmanfj]

My mechanic of choice loves them.

I'm not convinced enough to try them yet.     

Randy T
Indy

[Harvy]

Dan, funny you should ask....... just today I received an email from a local supplier about them, so I have ordered some. I'm intending on using them with the NEXT set of rubber.
I'll let you know what I think.

Cheers
Harvy

[Dan Filetti]

Please do.

Thanks,

Dan

[FJ Flyer]

Another guy on the Yahoo group (not sure if he's made the transition) that is a friend and lives near me used them on his '86.  He had limited results.

I just can't figure out the physics.  It seems to me if you have a heavy spot, the beads would naturally accumulate there, making it worse.  Kind of like a washing machine that is out of balance.

I'm skeptical, although if they work, it certainly would make life easier.

[ddlewis]

I hear good things from the dual-sporters re: dynabeads.   I've been tempted to try.  takes a lot of lead to offset a rimlock. 

Interested to hear what you think Harvey.

[Shaun]

Guys around here with 4x4s and big tires use airsoft pellets to balance them out and say they work fine. On the extreme end with barley legal tires some folks have been known to use golf balls, balances the tire in rotation but as you slow down you can imagine the effect/noise it would produce. I imagine the dyna beads work the same way a kind of dynamic balance so to speek. I've pasted an articale from a 4x4 web site 4x4 trail hunters the authors name is Eric. It is a good read and explains how it works. I know it is a 4x4 article but it relates directly to the question here, just on a different scale.

Enjoy the read.
Shaun

For those of us with large tires, 33" or taller, having perfectly balanced tires seems more a fantasy than a reality. Especially if your tires say Interco on the side. As you know, tires are normally balanced by putting them on a special machine which tells the technician where the tire is out of balance and by how much. They will attach weights to the side of your wheel and viola, the tire is fully balanced.

Why Reinvent the Wheel Weight?
So traditional wheel balancing sounds okay, but here is the problem. The larger the tire, the further away from the wheel the tire gets. That means the balancing weights are further from the tread and it requires more weight to balance the tire. Also, a larger tire weighs more overall and potentially could require more counter weights to balance the tire's greater mass. Add these two things together and there could me a lot of weight on the side of your wheel.

First of all, having 6" of wheel covered with weights is ugly and they can damage the finish on the wheel. Second of all, it's bound to get knocked off when you come in contact with a rock. It will happen eventually if you drive on rocks. You probably won't notice until you stop to air your tires up and that weight will be long gone and your tire is now out of balance.

The other problem is tire wear and how it affects tire balance. Tires don't always wear evenly. Even when they do, the weight distribution can change putting your tire out of balance. The only solution to this is to get your tires re-balanced every 10k miles or do one of the following.

This idea isn't really new, but the way you apply it has matured quite a bit. The idea is to move the weight as far to the outside of the tire as possible and to make it so the tire is always in perfect balance. The way to do that is to put weight inside the tire which is as far away from the center of the wheel you can get and use some sort of material that can freely move around to naturally balance the tire when it spins.

How it Works
The physics of how/why the free mass inside the tire automatically knows where to go is hard to conceptualize. The best way to understand why this works is to exaggerate the problem. Imagine there is a 5 lb weight fixed to one place on the tire. When you spin that tire to normal high way speeds, it will be so terribly out of balance that the tire would probably hope off the ground with every rotation. The axis of rotation is actually moved away from the center of the wheel toward this extra mass because it's pulling the whole tire with it as it spins. The free moving balancing weights inside the tire are not affected the same way by these forces. First as you get up to speed, centripetal force will make the balancing weight stick to the inside of the tire. Then the force of the imbalanced weight on the tire will move this balancing weight away from the imbalance. When enough of the mass is opposite of the imbalance, the vibration disappears and the axis that the tire is rotating on returns back to the center.

To give you another example to explain why the balancing weight moves away from the imbalance and balances the system, think about what happens when you accelerate fast in a car. Anything that's loose moves to the back of the vehicle. This same force is created on an imbalanced spinning tire. The imbalance is jerking the tire sending the free mass inside away from it and the centripital force holds it here.

What to Use
Okay, so we know the theory about why it works, but what do you use for the weight inside your tire? Over the years people have used some pretty strange things from golf balls, steel BBs to water. None of these are very good at balancing your tires. Golf balls have too much mass for each unit so they can't balance a tire as evenly as using many more less massive weights. BBs work well to evenly balance the tire because they're small and heavy, but their material is their downfall. Moisture does exist in your tire unless you always fill them with Nitrogen. The BBs will eventually rust and completely disintegrate over time.



Steel BBs that rusted. Pic courtesy of InnovativeBalancing.com

Water can work, but it is slower to align itself because of its high surface tension. Also, since you wouldn't use much, as far as volume, the water would have to spread thin and would likely evaporate after a season's worth of airing down your tires. Other substances like Nu-Mag, Equal, Magnum and other balancing powders are susceptible to clumping as they absorb this same moisture and they're not round, so they don't roll into position quickly.

There are a couple of commercially available products designed just for balancing tires. One company in particular, Innovative Balancing, has developed a product that works very well. They call them Dyna Beads. They are small ceramic balls that can be inserted through the valve stem. Since they are perfectly round, they quickly roll into position and adapt to balancing changes. They will not clump from moisture inside the tire. Since the media is small, they recommend a filtered valve stem so you don't loose any of the media when air is released.

Compared to other media and bolt on balancers, the Dyna Beads are a bargain. On average, to buy the media, filtered valve cores and the removal tool for four tires, you're looking at about $60. They claim their beads reduce the operating temperature of the tire and can extend tread life 35%. They have also developed a great chart which you can use to determine how much balancing media you need. Use it here, http://www.innovativebalancing.com/BigTirechart.htm.

Always one to save a buck or two at the expense of some effort, I found Airsoft pellets to be an excellent alternative that has most of the benefits of Dyna Beads and none of the drawbacks of the alternatives. Airsoft pellets are too large to fill through the valve stem and they are less massive per unit, so they're not as efficient as Dyna Beads, but still very good. They are perfectly round balls of high density plastic which will not clump from moisture or breakdown over time. I ordered 2 KG of pellets online for $26 shipped to my door.



1 KG of common Airsoft pellets

Installation (1 hr)
I got creative, but you can use a Hi-Lift jack to unseat the bead of your tires. Simply remove all of the air from the tire by removing the valve stem and place the base of the Hi-Lift right where the bead seats on the tire. Then position the jack underneight something heavy like a sturdy work bench or your rig and begin jacking. Once you get the hange of it, you can do all four in less than an hour. Please be careful, Hi-Lifts are dangerous and mix this with putting a lot of force on an unstable tire, you could get hurt. There are other products like Tyreplyers which are supposed to work well. Using Innovative Balancing's chart above to determine how much media to use, I dumped the pellets in and reseated the tire. One of the beauties of this system is its okay if you put more than the recommended amounts. In fact, it's better to go over than under because the extra material will just find a neutral place inside the tire and will not affect the balance.

Results
Now take it out and enjoy tires that are rebalanced every time you drive. I have to get up to about 20 mph for the pellets to stick to the inside of the tire and begin working. It's at speeds greater than 20 when tires need to be balanced. They will not fall off the tire until a you're below 5 mph. I can hear the pellets fall off when the window is down, but otherwise, I never notice they are there. My tires have never been balanced and they are worn very unevenly and ride terribly on the road. After using the pellets, the operation was noticeably smoother and quieter. All of the uneven wear has evened out. I'm sure using them from the beginning when the tires are new will yield greater gains than I have. I have yet to confirm the extended tread life claims because that's impossible to measure. Your driving habbits will influence this a lot.

[FJ Flyer]

How it Works
The axis of rotation is actually moved away from the center of the wheel toward this extra mass because it's pulling the whole tire with it as it spins. The free moving balancing weights inside the tire are not affected the same way by these forces. First as you get up to speed, centripetal force will make the balancing weight stick to the inside of the tire. Then the force of the imbalanced weight on the tire will move this balancing weight away from the imbalance.

To give you another example to explain why the balancing weight moves away from the imbalance and balances the system, think about what happens when you accelerate fast in a car. Anything that's loose moves to the back of the vehicle. This same force is created on an imbalanced spinning tire. The imbalance is jerking the tire sending the free mass inside away from it and the centripital force holds it here.

The axis of rotation can't change.  The center of gravity of the spinning wheel may shift, but its still rotating around the axle.  If not, you're in trouble.

And linear acceleration and angular acceleration are two different animals. 

I still don't see a legitimate scientific explanation here.   And the "hard to conceptualize" statement is a a cop-out, akin to the magic of putting magnets on your fuel lines to increase gas mileage because they say it works.  Not saying they don't work, I just want some hard evidence of why...

[Shaun]

Fair enough, that was just one persons opinion and his attempt at an explanation. I am not for or against them just noted that I had read something about them and had heard of them being used around here in a different application. However I do have some experience with a slightly different product, but the principle/outcome was the same. I say outcome because at the moment we do not have a definitive answer as to how it works. I was on a ride across Canada from British Columbia to Nova Scotia, part way across somewhere near Winnipeg on a Saturday afternoon a back tire change became critical. My chances were not that good of finding somewhere open, but on a secondary road I did find a motorcycle shop that was closed but with the owner sat on the front porch out of the sun enjoying a cold one. Long story short he wheeled my bike in the back and changed my tire. Just before he put the valve core in he walked over to a 45 gallon barrel and pumped something into my newly mounted tire. I was somewhat curious so the question, what was that? His reply "a tire sealer and an internal balancer, protects the tire from rapid air downs caused by road debris he said, and I don't have to spin your tire to balance it, just add air and ride, it balances as you go." So I did. He did show me what it looked like, it was a kind of green liquid slime, never went hard, never dried out always moving around inside the tire I guess, as it was still there the next time I changed the tire. I never had any problems with the green slime, my wheel did not have any external weights but my tire didn't have any vibration either. The tire ran just fine its entire life span on my bike with no problems. So far I have not been able to find this green slime again either though, maybe it was just a passing fad like the magnets in your gas line made to improve your fuel mileage, I don't know. Here is a link of a company that has produced a short video and a crude example of Dyna beads at work, www.crosshaircustoms.com choose Products scroll down. And as for a real technical explanation I have a Mechanical Engineer upstairs that may be able to come up with the solution as he likes things like this, so I'll ask him and see what he thinks and if he comes up with something real I'll post it up for you.

Cheers
Shaun

[racerrad8]

Here is the product you described: http://www.slime.com/index.php

Not sure of the balancing aspect of the product, but is does help with flat tires.

Randy - RPM

[FJ Flyer]

They sell Slime at Harbor Freight, saw it the last time I was there.  Yes, same principle.

I'm not saying these products don't work.  In fact, I hope they do.  But I'm a skeptic and I want the process explained a little better.  Given that Dyna Bead aren't that expensive, I may just give them a shot for the hell of it.

Appreciate your inputs and posting the info.

[jamesearthdrum]

I've been running them in my '89 for about 5000 miles now. Seem to be doing the job. I have not noticed any tire vibration that would be caused by out of balance condition. I am also not sure that I would know the difference.  My tires are wearing very evenly.  I have also read that tire manufacturers are getting very good at producing tires that need very little balancing. What we need is a controlled test. Maybe we can get Bill to try them at a track day? One day with and one day without.

[racerman_27410]

One of my riding buddies comes over to the shop to use our no mar tire changer and for the last three sets of tires he doesnt even want ot mess around with balancing them..... he says they dont need balancing (he runs michelin pilot powers exclusively) and by the way he rides i would say the difference between balanced and non balanced is minimal.

JMO % Kookaloo!

Frank

[FJ Flyer]

Sorry to dredge up the topic.  Couple weeks back, I spooned on some Pilot Road 2s onto the FJR.  Being brave, and perhaps naively optimistic, I decided to give the dyna beads a shot.  (Even though it was against my better judgment).  

I can now report that they don't work for shit.  Above 70 mph it gets pretty bad.  So there's another data point for those considering them.

I will probably invest in a Marc Parnes balancer and some weights.  

[SlowOldGuy]

I will probably invest in a Marc Parnes balancer and some weights. 

Hey Chris,
I use one of those, just be sure to order it with the longer rod.

It works great.  I just installed a Dunlop Roadsmart front tire last week and use the balancer to check the weight needed.  It appeared to need a single 20g weight.  As an experiment, I marked the location of the weight, removed it,  then took the tire to a local Honda dealer and had them balance it with their computer balancer.  They put a single 20g wieght right between the marks I made on the rim.  This is the second time I've done this and both times my home balancer matched exactly what a computer balancer says a tire needed.

Get a couple of sheets of their stick-on weights.  I reuse weights all the time.  Just remove the old stickum and use a little silicone to hold them to the rim.
DavidR.