Tire Balancing Beads

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WardPAW
Posts: 76
Joined: Tue Feb 04, 2014 10:03 pm

Tire Balancing Beads

Post by WardPAW »

Has anyone has installed tire balancing beads? Is your ride improved? Did you have better tire wear and extended tire life?

This link is a Good Sam RV Tech discussion forum about the topic.

http://forums.goodsamclub.com/Index.cfm ... 400956.cfm
Ben Ward
2005 26 RSB, Diesel
RV Name: Lion PAW
User avatar
cmeadows
Posts: 156
Joined: Sat Mar 02, 2013 5:54 pm

Re: Tire Balancing Beads

Post by cmeadows »

Ben,

The ride, tire wear and extended life of the tire while balanced with beads would be the same as with rim mounted weights—so long as the rim mounted weights keep the tires balanced for every service life mile of the tire. The primary benefit of using beads is that you don’t have to rebalance the tires. Because the tires are always in balance, the tread life is not compromised by running partially out of balance until the next rebalance. Beads keep the tire in balance and as a result they usually wear more evenly. Beads also balance the entire wheel assembly including the stainless steel wheel liner and air hose extensions.

Beads work great on the Born Free tires. I use beads instead of rim-mounted wheel weights and they run smooth as silk. I put in 3 ounces per tire when the tire is mounted to the wheel. The beads that I use will not fit through the valve core so they must be added while the wheel is off the coach with one side of the tire pushed off of the rim enough to pour them in.

Using beads for a static tire balance is not magic, it's physics. Beads will not correct an out-of-round tire or dynamically out-of-balance tire. If a 225/75R-16 tire on a Born Free doesn't balance with beads, then it is either: out of round—replace the tire; or out of balance dynamically—have it computer balanced with rim mounted wheel weights to correct for dynamic balance and then add beads for a long-term static balance. If you have any doubt about the dynamic balance condition of your new set of tires, you can have them computer balanced to correct the dynamic balance and then leaving the rim weights intact, break down one side and add the beads for a long-term static balance.

There are lots of brands of balancing beads and powders out there. Many are ridiculously expensive. I use Crosman "High Impact" .25 grams 6mm airsoft BBs (available at Wal-Mart). There is nothing special needed to use these beads. They are too large to come out of the valve core so they stay in the tire when adding/removing air—no need for a special filtered valve core. They are made from a polymer and will not rust. I weigh them with postal scales and put 3 ounces worth of these in each tire when mounting. I also keep a couple 3 ounce pre-measured zip-lock bags of these beads in the coach in case we ever need tire repairs while traveling.

http://www.amazon.com/Crosman-AirSoft-5 ... B003QNGOTY

About the only negative to using these beads is the slight tinkling noise when slowing down to a stop. When gravity regains control of the beads from centrifugal force, you may hear them tinkling down onto aluminum wheels. With the stock steel wheels on a Born Free, you might faintly hear them with the ac/heater fan off, the radio off and the windows down. In a diesel coach it is difficult to hear them at all. In a silent electric car, they can be heard about every time you stop. :D The noise doesn't bother me at all and others in the vehicle never hear them at all.

Below are links on the site to other discussions that mentioned using beads for tire balance.
Chuck

http://bornfreervclub.org/bulletin_boar ... ilit=beads

http://bornfreervclub.org/bulletin_boar ... ilit=beads

http://bornfreervclub.org/bulletin_boar ... ilit=beads

http://bornfreervclub.org/bulletin_boar ... ilit=beads

http://bornfreervclub.org/bulletin_boar ... ilit=beads
Chuck & Laura Meadows
'99 24RB PSD
WardPAW
Posts: 76
Joined: Tue Feb 04, 2014 10:03 pm

Re: Tire Balancing Beads

Post by WardPAW »

Chuck,
Thanks for the detailed response and other links. Sounds like the beads are the way to go, especially since the beads will balance the whole wheel assembly (rim, tire, wheel cover and valve stem extender).
Ben Ward
2005 26 RSB, Diesel
RV Name: Lion PAW
Nancy
Posts: 172
Joined: Sun Aug 14, 2005 8:01 pm

Re: Tire Balancing Beads

Post by Nancy »

got em and love em.
2005 26' RSB Casual Elegance
oliverpsmile
Posts: 271
Joined: Thu Dec 18, 2008 2:46 pm

Re: Tire Balancing Beads

Post by oliverpsmile »

..... weights to correct for dynamic balance and then add beads for a long-term static balance....

Chuck,
What is a long-term static balance and how is it achieved with beads?
Oliver P Smile
2005 26ft RSB
User avatar
cmeadows
Posts: 156
Joined: Sat Mar 02, 2013 5:54 pm

Re: Tire Balancing Beads

Post by cmeadows »

Oliver,
That's a good question. Let's start by looking at the definitions for static and dynamic balance as they pertain to tires, then we'll look at what beads can and cannot do, cover a little science, and finish with how beads work. Below are links to 5 sites that offer varying levels of detail to explain static and dynamic tire balance.

Define Static and Dynamic Balance
Bridgestone Truck Tires – Why are there TWO kinds of Balance?
http://www.bridgestonetrucktires.com/us ... doctor.asp
This link contains good information but with red print on a blue background, it is difficult to read. If you click your curser on the site's text and "Select-All" in your browser (with Control-A or Ctrl-A), it is much easier to read while the text is selected. Also, while not documented in the legend, the little blue squares with a white "W" on the tire graphics indicate where the weights are placed—this is helpful in understanding the corresponding text. (Deselect the text to see the weight markers.)

AGCO Corp – Wheel Balance, Shimmy and Vibration
http://www.agcoauto.com/content/news/p2_articleid/110

Road Force Touch – What choices do I have in balancing a wheel?
http://www.gsp9700.com/technical/4202T/6GLOS003.htm

Wikipedia – Tire balance
http://en.wikipedia.org/wiki/Tire_balance

Balance Technology Inc.
http://balancetechnology.com/resources.html
Balance Technology Inc. has great information on the physics involved in all types of balancing available in 2 downloadable PDF documents: Basics of Balancing 101 and 202. The sections in each document for "Static Unbalance" pertain directly to bead balancing.

Bent Wheels and Out of Round Tires
Beads won't help bent wheels and out of round tires. While bent wheels and out of round tires can be corrected for balance—both dynamic and static—they will not roll smooth. A square tire could be balanced but it won't roll smooth. Circles roll smooth. Wheels can be checked for roundness runout with a dial indicator. With the tire removed from the wheel, spin the wheel on a front axle hub and take measurements. I like to see measurements less than .035" for both roundness and wobble on a 16" steel wheel. Out of round tires can be more difficult to measure. Drive a few miles with the tire in question mounted on the front to get it warm. Jack up the front axle and slowly spin the tire. Use a jack stand as an axle-high reference point and use a ruler to find the high and low points of the tread. The tire runout should be less than 3/32" (or about .090). Unfortunately, some tires that are out of round may not show the severity of the defect until reaching highway speeds.

As an alternative to measuring rim and tire runout, a shop with a Hunter Road Force Balancer has the equipment to detect runout/roundness problems. As a troubleshooting tool for out of round tires, the Road Force balancer is a great machine. The idea is to match the tire runout with the wheel runout for the lowest runout match possible on the tire/wheel assembly—before adding rim weights. The challenge is to get the operator to take the time to measure the runout (force in pounds) and break down and remount the tire as many times as necessary to get the best match possible before adding wheel weights. In practice, it really depends on the operator's skill and level of effort applied to solve the problem—the same applies to all operators and balancing equipment.

Hops & Wobbles
Beads will cure hops but not wobbles. For an oversimplified description of what static and dynamic balancing do for a tire/wheel assembly, it all comes down to Hops & Wobbles:

Hops — caused by a heavy spot on a single plane (static imbalance).
Wobbles — caused by the two sides of a tire having differing heavy spots (dynamic imbalance).

Hops are corrected when weight is applied 180 degrees across the plane from the heavy spot. This is static balance and can be measured with a simple bubble balancer. Hops can be corrected with beads.

Wobbles are corrected when weight is applied along 2 planes: the inside rim of the wheel; and the outside rim of the wheel. The most common way to measure for wobbles, or dynamic balance, is with a computer balancer where axis forces are calculated for the inside and outside planes of the wheel. Rim weights are mounted in fixed locations along these two planes. Once corrected with fixed weights, the relative side-to-side balance does not change—at least until tire wear causes a new imbalance.

When beads are used inside a tire, they travel in the circumference center plane of the tire. Because of this, beads are only helpful in achieving a static balance. If beads are used in a tire with bad dynamic balance, the wobble will persist as beads have no ability to correct for a side-to-side imbalance—they just ride along in the center plane, keep the tire in static balance, and have no positive or negative effect on the side-to-side wobble.

After the dynamic balance has been corrected with computer balancing and rim mounted wheel weights (if needed), beads added to the wheel assembly will keep the tire in static balance for the life of the tire. This represents the long-term static balance and the beads prevent the need for additional computer balancing with rim mounted wheel weights. (In practice, I usually start with good tires, skip the computer balancer, put beads in the tires, and go for a test drive. If a tire is manufactured with a slight dynamic imbalance, it is often minor enough so as not to cause a wobble.)

Static Imbalance—Rotational Mass Axis vs. Wheel Axle
Because an object of any shape will rotate around its center of mass, an out of balance tire rolling down the road will have its heavy spot move in a circle the closest to the rotational mass axis while the lightest portion of the tire will circle the farthest away from the rotational mass axis. This, of course, is limited by the vehicle's spring travel and shock absorber dampening the movement.

The problem is that the tire/wheel assembly already has an axis—the axle to which it is mounted at the dimensional center of the tire/wheel assembly. With each axis, the rotational mass axis and the physical axle hub, claiming rotational rights, the tire/wheel assembly will attempt to satisfy both and roll in more of an oval path instead of a circle—it hops instead of rolls. For the tire/wheel assembly to be in balance and roll smooth, the rotational mass axis (which is force derived) must be moved to match the point of the fixed axle axis. This is accomplished with weights to counter-balance the heavy spot on a tire.

Photo 1 — Rotational Mass Axis away from Axle
If a hammer were round like a tire, it would be severely out of balance. For this hammer/tire example, ignore the fact that a hammer is not round. Drawn circles will represent the hammer/tire to make it round.

The gray tape represents the dimensional center and lug nut mounting point for the hammer/tire. The gray arrow points to the vehicle axle/hub to which the hammer/tire is mounted. The gray circle indicates the outline of the hammer/tire rotating on the vehicle's axle.

The blue tape is the mass balance point of the hammer/tire and the blue arrow points to the rotational mass axis. The blue circle indicates the outline of the hammer/tire rotating on the mass axis.

The hammer/tire is shown balanced on the chair at the blue tape. This is the point and axis upon which the hammer/tire will rotate according to its mass. This point is not fixed and can be altered with the addition of balance weights. The gray tape representing the axle/hub is a fix point and cannot change because the hammer/tire is bolted to the vehicle with lug nuts. The objective is to align the blue and gray arrows to balance the hammer/tire. As shown, the distance between the blue and gray arrows indicates that the hammer/tire is out of balance (by a large amount) because the rotational mass axis and the vehicle axle are not at the same point.

Photo 2 — Rotational Mass Axis Matching Axle
When we add weight to balance the hammer/tire, the mass balance point and rotational mass axis (the blue marks) are moved to the center of the hammer/tire. With the blue and gray marks aligned on a point, the hammer/tire is now in balance. The rotational paths are the same, the rotational mass axis and the vehicle axle are the same, and the hammer/tire will now roll smoothly down the road. (Ok, so it's not quite round enough for a smooth ride, but you get the idea.)

How Beads Work
Balancing the tire is a byproduct of the beads trying to escape. (For simplicity, we will recognize centrifugal force.)

Beads will correct for static balance where weight is applied 180 degrees across the plane from the heavy spot on the tire/wheel assembly. Unlike fixed rim mounted weights, beads are loose inside the tire and are free to go wherever the forces take them. As the tire rotates, the beads move around freely until around 20 mph when centrifugal force keeps them at the outer circumference of the tire.

While the beads are held captive inside the tire, they are still trying to escape—outward—away from the axis. Because of this, the beads will travel along the circumference of the tire until they find the longest radius away from the rotational axis—a point 180 degrees across from the heavy spot on the tire.

In the hammer/tire example in Photo 1, the longest radius distance from the rotational mass axis (blue arrow) is to the lightest spot—the end of the hammer handle. In the same photo, the shortest distance from the rotational mass axis (blue arrow) is to the heaviest spot—the head of the hammer. Instead of using another hammer for balance weight, we could use beads. When the hammer/tire rolls up to speed with beads for balance weights, the beads would accumulate at the longest radius (end of hammer handle) and balance the heavy spot (the hammer head.)

Remember that the rotational mass axis is not fixed and will move with a weight shift—as shown in Photo 2 where the blue arrow is in center rather than near the hammer head. If too many beads accumulate at the end of the hammer handle (the longest radius), then the handle will become the heavy spot and the radius will thus be shortened as the rotational mass axis moves toward it. The result of a heavy handle with the beads is that the hammer head will have the longest radius and beads will travel to it. The beads are still just trying to escape by finding the longest radius.

As some of the beads start to travel toward the hammer head, the rotational mass axis will change again and alter the radius lengths. This continues until the rotational mass axis settles to a point whereby all of the radiuses are equal and the beads have nowhere else to go to try to escape the tire. With the beads settled in and the radiuses being equal, the rotational mass axis is aligned with the fixed axle/hub (the dimensional center of the wheel), and . . . this also means that the tire is balanced.

Through the movement of the beads, normalization occurs and the beads settle in with just enough beads to equal the heavy spot located 180 degrees across from the heavy spot in the tire. The remaining beads that are not needed to counter the weight of the heavy spot then neutralize around the circumference of the tire cancelling out each other. The result is a tire assembly that is in static balance.

Once up to speed (around 20 mph when centrifugal force captures the beads), the balancing activities are completed in less than a couple seconds. This will occur whenever the tire gets up to speed—a perfect balance every time.

Chuck
Attachments
photo 1 -- rotational mass axis away from axle.jpg
photo 1 -- rotational mass axis away from axle.jpg (279.61 KiB) Viewed 16822 times
photo 2 -- rotational mass axis matching axle.jpg
photo 2 -- rotational mass axis matching axle.jpg (250.5 KiB) Viewed 16822 times
Chuck & Laura Meadows
'99 24RB PSD
Ray

Re: Tire Balancing Beads

Post by Ray »

Wow - Thats allot of info to absorb, Thanks for taking the time and effort to put this together. Ray
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CuJo's Pride
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Re: Tire Balancing Beads

Post by CuJo's Pride »

Thank you so much for explaining this in such detail. This is fantastic info.

Perfect..
Curt and Jo
Our Springer Spaniels - Betsy and Moxie
Member of The Born Free Leap'n Lions
"BeMo" is our 2004 26'RB
Trex 27 Speed Tandem Bicycle
oliverpsmile
Posts: 271
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Re: Tire Balancing Beads

Post by oliverpsmile »

Chuck

Thanks for the References. Balancing 202 was the most detailed.

From the Paper: "Dynamic balancers rely on the effects of centrifugal force to detect unbalance. They are
capable of detecting all forms of unbalance static, couple, dynamic or quasi-static."


So once the tires are PROPERLY balanced on a computerized balancer - it appears that the beads really help in a long run by automatically (adding and/or removing weighs) correcting ANY UNBALANCE which may be developed over normal wear and tear. The exact definitions in the paper clarified this subject for me.
Oliver P Smile
2005 26ft RSB
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cmeadows
Posts: 156
Joined: Sat Mar 02, 2013 5:54 pm

Re: Tire Balancing Beads

Post by cmeadows »

Oliver,

I agree that a computerized balancer will correct for all types of imbalance. One thing that I didn’t state before is that a tire in dynamic balance will also be in static balance.

The two-plane balance correction used in computerized balancers boils down to addressing only static and couple forces. Beads will correct for static balance. Beads cannot correct for couple force imbalance. Beads will correct the static portion of a dynamic imbalance which leaves behind an uncorrected couple force imbalance—the same applies to a quasi-static imbalance. Of all of the unbalances in a tire, static is usually the largest by force. Measured by the corrective weight applied, a dynamic unbalance is often comprised of 2:1 static to couple force imbalance.

Tires balanced on a computerized balancer are ready for the road, but they will be slightly out of balance. These variables work against perfection:

• Weight tolerance for the balancer to display 00.00 representing a perfect balance. Depending on the machine, the tolerance can be 1/4, 1/2, or on some machines even 3/4 ounce and still display the perfect 00.00 reading. If you find a willing operator, have them push the "fine" button that shows the true balance reading in 1/10th of ounce increments overriding the default imbalance tolerance of the machine. (Expect scowls for this request—it takes time to balance within 1/10th of an ounce.)

• Calibration of the balancer. As a calibration check, after a tire has been balanced, ask to have your tire rotated 90 degrees on the balancer shaft and spun again. (Expect more scowls.)

• Accuracy of the operator placing the weights on the wheel. The operator should spin up and check the tire balance after adding wheel weights (preferably in "fine" mode).

When beads are added after the tire is computer balanced, the above points become irrelevant. The beads will correct balance imperfections left by the computerized balancer. For the beads that I use, this costs about a dollar per tire.

Chuck
Chuck & Laura Meadows
'99 24RB PSD
WardPAW
Posts: 76
Joined: Tue Feb 04, 2014 10:03 pm

Re: Tire Balancing Beads

Post by WardPAW »

I finally had the balancing beads installed in our tires about a month ago. The lead weights were left on the rim and beads placed in the tire. Noticeable difference right away in the ride.

My test for better tire balance is the 7" GPS we suction cup to the front window. The GPS no longer has a shimmy as we drive down the road.

The local tire store used Magnum Plus balancing beads. 4.5 oz package per tire which includes a replacement valve stem insert.
Ben Ward
2005 26 RSB, Diesel
RV Name: Lion PAW
ddbowen

Re: Tire Balancing Beads

Post by ddbowen »

Wow Chuck!! Splendid white paper on road force balancing. Your post should be sticky. Best of all you've obviously spent some time around technicians. Are you headed to Humboldt in June?
rhyde

Re: Tire Balancing Beads

Post by rhyde »

Chuck,
I wish my engineering instructors (Maine Maritime Academy 1974-78) had your skill at explaining basic engineering principles. It would probably have helped my grades. Excellent explanation!
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cmeadows
Posts: 156
Joined: Sat Mar 02, 2013 5:54 pm

Re: Tire Balancing Beads

Post by cmeadows »

WardPAW, your stability test with a 7" gps on the windshield sounds like a great check for tire balance. Glad to hear your tires are rolling smooth with beads.

Ddbowen and Rhyde, thank you for the kind words. The kids have scouting events in June so we will be unable to make it to Humboldt.

Oliver P Smile prompted the explanation on beads by asking a reasonable question. I wrote a response after first searching for but not finding a satisfactory answer on the topic. So, hats off to Oliver P Smile for asking the question.
Chuck & Laura Meadows
'99 24RB PSD
Mary

Re: Tire Balancing Beads

Post by Mary »

I have searched on line and looked at my local Wal-Mart and cannot locate the Crosman High Impact BB's that some suggest to use as balancing beads. Everyone seems to be out of this product.

I have located one site on line that still has a few in stock. It doesn't list them as high impact but it is the same manufacturer (Crosman) and the BB size is the same. Oops, I don't know how many jars to order.

Would someone please tell me how many jars of BB's I'd need to order to use for 6 new tires? My sincere thanks for the assistance.

Does this sound like the correct item?
Crosman Maximum Precision 6mm BB Blk .25g /5000 25GPB5J

Maximum Precision 6mm BB Blk .25g (Per 5000) | Game Face Airsoft Maximum Precision BBs

Features:

- Double Polished
- .25g Maximum Precision BBs
- 5,000 count in a bottle
- Black

Specifications:

- Caliber: 6mm
- Color: Black


Model: 257319
Shipping Weight: 2.85lbs
11 Units in Stock
Manufactured by: Crosman
UPC: 028478143050
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