I just finished installing a front tire on my sport bike and a rear tire on my FLHP-I. Instead of the dynabeads, I used the 0.25 gram Airsoft "BBs" like I have read that others have used. Of course, they can't be installed through the valve stem, but since I'm replacing the tire, it's not a big deal to toss them in prior to setting the bead. I put 115 in the front tire and 230 in the rear tire. By my calculation, that should be 1 oz and 2 oz respectively. I did not notice the previous tires having *any* balancing weights on the wheels.

 

FWIW to those considering these, in the Oct. 2006 issue of Motorcycle Consumer News, Dyna Beads were tested and found to be ineffective. I couldn't find an on-line copy of that test but did find a summary from the Dec. 2010 issue:

"MCN evaluated the Dyna Beads on a reader's suggestion back in October of 2006. Although the tiny white ceramic beads have apparently found favor with long-haul truckers, we tested them in 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 then 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."

I have no first-hand experience with Dyna Beads and am not trying to rain on anyone's picnic, but just offer this info as a FYI.

 

First time bead user in new E3's, some say " snakeoil ", and a mag sez ineffective, can't prove if it's just a good set of tires or what, but the end result for me is no vibes at all, very smooth (2500 miles on tires).

 

I just installed them in a new rear tire and work great.

 

Dyna beads will show an imbalance on a spin balancer. This test was performed by folks who do not understand physics. There are some very rare occasions where the harmonics of the tire and rim combination will not allow the dyna beads to compensate, but most of the time they work great. They are not snakeoil and there is some very sound physics behind the principle they rely on. Just don't try to spin balance them with dyna beads in.

 

What are these sound physics? It seems to me that if you put spherical items in a tire, that they will evenly space out around the outer limit of the tire when the bike reaches a high enough speed for them to spread out. If they are evenly spaced, how could they correct an imbalance? Wouldn't that just add mass evenly around the tire? It's not like they could actually hunt out an imbalance in the wheel and counteract it. Besides, new tires SHOULD feel a lot better than old, worn out tires.

I'm not saying anyone is full of sh*t, but if anyone has an explanation behind how they actually work, I'd really appreciate it.

 

So spinning on a balancer is different than spinning on a bike? Please explain the physics.

 

I don't know much about physics

I try to picture how they work too,...... probably an opposite reaction to the unsprung weight trying to lunge or move towards the heavy spot. Centrifugal force keeps the beads in contact with the tire and they roll opposite of the highest force, then stay put when the forces are equal.

Maybe the wheel assy needs more freedom of movement for the beads to work, rather than mounted to an almost fixed axle of a balance machine.

Just a guess

 

http://www.innovativebalancing.com/HowItWorks.htm

The principle of dynamic balancing relies to some extent on the movement of the wheel within the suspension system. The wheel not only needs to go roundie roundie, but up and down. The spin balancer does not typically allow enough up and down to assist the beads in repositioning. Centripetal force will tend to lock the beads against the tire to quickly without some agitation from the up and down. Just sayin.

 

Right on, you are correct. Where did you get your physics degree at.