High speed vibrations with Dyna Beads

Discussion in 'The Garage' started by tututis, Jan 16, 2010.

  1. BossMaverick

    BossMaverick Been here awhile

    Joined:
    Jan 6, 2012
    Oddometer:
    279
    Actually, most top-loading washing machines have a hollow ring that is partially filled with liquid (my guess is just dyed water because it can freeze). The balance ring is mounted on top of the washer's drum. The liquid inside the ring acts as a dynamic balancer, much like how tire beads are supposed to work. The ring does the vast majority of the balancing for the washer's load. Due to the ring containing only a couple pounds of liquid, it cannot balance extremely off-centered heavy loads, especially if there is a broken mounting spring, or if the drum "skateboard" pads are worn and sticky, or if the washer used is on a weak floor.



    I'm wondering if the people that are having balancing bead problems just don't have tire, wheel, and suspension combinations that have a natural resonance or springiness that can't be eliminated, or are made worse, by free moving beads (much like a washing machine that is on a weak or bouncy floor). It would be interesting to see if bikes with relatively weak or flexible forks are more likely to have balance issues with tire beads than bikes with stiff forks (like typical sport bikes). I also wonder if steering and suspension geometry plays a part in the equation.

    I believe in the concept of how tire beads work, but I also see issues with how it is executed. I imagine rim mounted balancing rings that contain a non-freezing liquid would work better than beads, but the added cost and risk of damage to the ring would outweigh the benefits.
    #81
  2. ultane

    ultane sqeezin the bag

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    ...And as pointed out by Woody some time ago, no amount Dyna Beads or wheel weights will make an out of round or untrue wheel ride smooth.
    #82
  3. WacoDirtryder

    WacoDirtryder Been here awhile

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    Aug 3, 2009
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    343
    Location:
    waco, texas
    They work great for me when i bought my GSA the tires were new and he told me he added beads. When i put on a new set of tires i lost some of the beads in the front tire on the change and it didnt seem as smooth then.
    #83
  4. Süsser Tod

    Süsser Tod Long timer

    Joined:
    Dec 29, 2010
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    Location:
    Mexico City, Mexico
    Gave them a fair chance, I'm not using them again.

    First time it was not my choice, I needed a new rear tire in Lafayette, LA and the shop that installed the tire used Dyna Beads instead of balancing the tire. It was not like I had many options on a Saturday to get the tire installed, so I went with it. At first they seemed to work, but over time I noticed that sometimes the bike would vibrate, sometimes it wouldn't. I found out why when I replaced that rear tire, the lazy ass mechanic had just tossed a bad with beads in the tire, about half of them were still inside the bag, so depending on the position of the bag the tire would balance or not...

    At first when I removed the tire I thought of just tossing them to the bin, but when I noticed the bag I knew I couldn't just blame the Dyna Beads, so I saved them.

    Then I put a new front tire. According to their chart it only needs 1oz:

    Tire Balancing Charts for Light Truck, Commercial and Motorcycles

    I had more than 1oz of the stuff, so I used them on the front. They work "fine" at lower speeds, but over 75 it vibrates, closer to 100mph and it vibrates wildly, at 100mph I had blurred vision and the vibration was so bad I could see the front wheel jumping. I know my Versys can do 120mph but I never tried that. Heck, I used to cruise at 90-100mph, but with the Dyna Beads that was simply out of the question.

    I had to take them out, and this time, I did toss them into the bin. To make things worse the first time I removed them they were on a rear Dunlop Q3 and they were clean, nothing came out of that tire other than the beads and air. This time, on the front tire, there was a lot of black rubber dust. They did not embed to the inside of the tire, but they did rub off some rubber. You know that Dunlop won't honor the warranty on a tire that had Dyna Beads?

    Guess what? It took exactly 1 oz, 4 x 1/4oz, of wheel weights to balance the tire properly, and now the bike is back to being smooth as silk at 100mph.

    Eff them. Stick on tire weights work just fine and I can re-use them, just peel off the old adhesive and put new double sided adhesive in them. The stupid Dyna Beads end up being more expensive over time, just to save 5 minutes that it takes to balance a tire?
    #84