Tape a wheel weight inside the rim of a Frisbee and throw it. OK, maybe you don't actually need to because you know what'll happen, right?
Back to the wheel balancer.. a dynamic wheel balancer (aka SPIN balancer, aka High-Speed-Spin-Balancer) uses sensors around the axle that measure displacement of the axle by the imbalanced wheel/tire.
Every one of them I've played with - the shaft through the balancer has some movement in it, restricted by the transducers and/or suspension of the motor driving the shaft. This movement should allow the beads to work if they work by displacement of the tire by the imbalance condition.How a Wheel Balancer Works:
The computer within the balancer receives the premeasured values of wheel dimensions and responds to the output of a rotational speed sensor that monitors the rotational speed of the shaft. When the required speed is reached, the mechanical system automatically decouples the powered cranking shaft from the wheel shaft so that there can be no externally applied disturbances for the subsequent measurements of imbalance. Multiple spaced transducers along the shaft determine the wheel run-out attributable to imbalances in both the inner and outer wheel rim planes and the computer provides output signals indicative of the correct balance weight and the mounting positions of the weights on the wheel rim.
I can't see why this wouldn't work to test how well Dynabeads work..
I guess I think they work a bit differently than everyone else. I don't think the beads optimize the suspension, but the suspension is required to initiate the distribution of the beads. Hard to say if a spin balancer has enough movement. The beads may not balance "the wheel", but they balance the rotating wheel/tire assembly when it's rotating above say 25MPH.
Here's what I was thinking.
When the bike is stopped, the beads are at the bottom of the tire (obviously).
When the tire first starts to rotate, the beads distribute evenly around the inner surface of the tire.
As speed begins to increase and the wheel heavy spot crosses the center line of the suspension, the inner surface of the tire accelerates away from the beads. The only place for the beads to go is to flow/roll along the inner surface of the tire towards the light spot of the wheel/tire assembly. Lots of beads move at first and fewer with each additional rotation.
After say 15 tire rotations (just a guess), the beads are fully distributed. They aren't evenly distributed. They are thicker directly across from the heavy spot and taper back with fewer and fewer beads around the inside surface of the tire until you have no beads at the heavy spot.
As long as you stay above 20 to 25 MPH, the force of the wheel rotating holds the beads in place and the tire/wheel assembly is balanced.
As the bike slows below 20 to 25 MPH, the beads migrate back around the inner surface of the tire (proportional to the speed drop). When that happens, the tire/wheel assembly is out of balance, but the speed is so slow you can't feel it. As the bike comes to a stop, the beads drop to the bottom of the tire.
Since you only put in 1 or 2 oz. in a motorcycle tire, there a pretty low limit to how much imbalance they can work with.
Just a thought
Now put the axle back in. The axle will move with the wheel. Now put a motorcycle on that axle.
The axle of a motorcycle is not a rigid support and does not keep the wheel from following its eccentric path. If it really stayed stationary, we wouldn't need to balance wheels at all because you'd never feel the effect of the imbalance. But clearly the tail is wagging the dog to some extent when we ride.
What effect do you think actually makes the imbalance that you feel? That might be a better place to start.
Putting theory behind us, I think the best thing for someone to do is take a tire and force it unbalanced with weights and ride the bike. Keep adding weight until you can feel the imbalance.
Now add the beads to the unbalanced tire and ride again. Did it work. Yes or No?
While I don't use them, (not sure if it would be good with TPM) most of the reports I've read are positive. I may try them on my old Turbos next time around because I hate weights on the gold wheels...
Anyway, assuming that it does work, I can see that there could be a problem of not enough beads in the tire to spread around. I would think that the texture of the inside of the tire would have a bearing on this. Smooth surface would allow a few beads to move where ever they want, but I've seen tires with patterns of shallow pockets in them which could prevent the beads from flowing like they should. More beads should allow them to fill the pockets and flow.
One main reason I don't use them? I change tires for seasons... Metz in the summer and Avon's in the winter... Drilling holes in a perfectly good tire to capture beads is idiotic.
The other reason? I have the equipment and I can balance often. Why play with beads when I can inspect my tires and rims when I remove them for one purpose or another. And keeping my rims clean is a purpose...
The dynabead guys seem to be pretty upfront about where they work and where they don't. There's a pretty good FAQ here...Originally Posted by dstuckmann
BTW, no financial interest on my part with dynabeads. I've been using them for a couple years and think they've been a terrific product.
The dynabeads aren't going anywhere. As you take the tire off, the dynabeads will stay inside the tire carcass unless you forcefully try to eject them. After the tire's off, if you stand the tire upright, the beads will all roll to the bottom of the tire. I just use a small parts brush to sweep them into a plastic spoon. It takes about 30 seconds. I put them in a ziploc bag. When the new tire goes on, after the first tire bead goes over the wheel, I snip the corner of the ziploc bag, pour the dynabeads into the new tire, and then put the second tire bead on the wheel. It's a pretty low effort, non-destructive process to reuse the dynabeads.
Last edited by alzyck; 06-24-2010 at 08:13 PM.
So there you have the rest of the story...
Yup, it sure would have been nice to know that they were in there.
I hear that a good way to remove them is to vacuum them out with a small nozzle once the tire bead is broken and one side of the tire is cranked out of the rim. The trick is to insert a sock between one of the hose connections and then the beads are bagged for you too!
This is better than an "Oil Thread". Where is Paul Glaves on this one? All I know is my front tire dosen't cup any more and my wheels feel balanced.