dyna beads

DSN_KLR650
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beachmike1
Posts: 41
Joined: Tue Feb 23, 2010 3:57 pm

dyna beads

Post by beachmike1 » Fri Aug 13, 2010 2:16 am

OKay I thought this through a bit. The web site does not give a wholly accurate picture of the issue of an out of balance tire beig affected by these weights but it is not bad. On the surface it may seem like snake pils but bear with me on this.. If we assume the inside of the is close to a perfect circle in the radial direction then at a steady stae with no load these beads will settle against the max radius by centripital accereation. Okay so far? Next assume first the case where the tire is out a balace and the heavy part is moving from the bottom of the half circle of rotation (defined by an iamginary line dividing the assembed system n the bike into a top and bottom half. the bottom hafl containing the contact patch. As the heavy part moves toward the top of the cicle we mentioned the force it applies to the axle is translated to the suspension and the tire can unload slightly for the contact patch in a slight verticle movment. THe teory is with this acceleration (forget the centripital for a sec, ) the tire moves(say ) up the beads on the bottom half of the tire move up as they are stuck to the tire by the centripital acceleration an the beads on the top half also move up. So far physics seems good but no balancing takes place......HMM The force to from roattion is much greater than the force from the unbalance. However the force on the beads is a bit diffferance. You have to thin a bit in vectors here. The force from the centripital accelleratio acts agains the beads radially (outward) and is the same for all beads. (forget the contact patch for now). the force form the accelation due to the vibration however is directed in this case in the direction of translation! So the beads on the bottom have this force applied throught the tire casing to their bodies toward the heavy spot (which is forcing the tire "up". the beads on the oppisite side DO NOT HAVE ANY FORCE FROM THIS MOVEMENT APPLIED to them because the acceleration is that of the tire carcass moving "UP" where the they are touching the tire. If the air in the tire was abe to tranmit loads it would carry the accelleration to the beads on the top half. SO it should work. HOWEVER. The beads at the bottom are beig distrubed every time the teir contact patch moves throught rotaion laong the face of the tire radially. The beads therefore are in near continuous motion. ther can be an issue with tore wear and oil water and other crude wearing the back side of the tire and making a bunck of powder that would interfere with this action. I cannot determine a reason these would not work as long as you only put in saw 20 to 40 grams. Much more that that in a street tire will cause another issue with continuing force being back feed into the sterring from the beads constantly moving with the contact patch. Interest stuff. Personally Ill stick with solder and a plaesant after noon working on the bike.

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