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What gives a string more repulsion?

Discussion in 'Badminton String' started by JoeyC., Mar 3, 2007.

  1. JoeyC.

    JoeyC. Regular Member

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    Hi, I was wondering why some strings such as bg-80, bg-66 say they have more repulsion then strings like bg-65, is it because of their thickness or some special core? I mean lots of people seem to prefer strings with more repulsion, but could the repulsion part be all in the head, from the advertisements?
    I personally don't find much difference in strings except for tensions. But that could be me.... so does a more repulsive string really give "more repulsion"?:confused:

    Thanks!
     
  2. Dummey

    Dummey Regular Member

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    Repulsion, as far as i know, has to do with the ability of the strings to stretch and go back to it's shape. The less it stretches then the less repulsion you have.
     
  3. taneepak

    taneepak Regular Member

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    The string consist of a center core and an outer jacket. It is the center core that determines a string's strength, resilience, and the source of a string's power. The outer jacket determines a string's abrasion resistance and control. Filaments in the center core can come in one monofilament, or many multifilaments, or in even more (counted in the thousands) microfilaments. Given the same diameter core, a monfilament will feel hard and has the least power. Next one up is the multifilaments type, in which the hundreds of filament, that go into the same size core as the monofilament, are finer, more resilient, and therefore more powerful. The next higher step is the microfilaments that go into the center core. Because we now have thousands of filaments that go into the same core, the resilence is even greater, and so is the power. Given the same tension, the higher count filaments string will have more power because of their greater resilience. Some will use the words hard and soft to describe a smaller number of filaments string vs a greater number of filaments string.
    If you own fine Persian carpets and walk on them barefoot or sleep on 700 threads per sq inch bedsheets, you will know what I mean.
    As an example, Yonex at least tries to explain that their BG80 and BG85 should be strung at a tension that is 10% lower than BG65 if you want to have the same 'feel'. The real reason for this is that the vectran in BG80 and BG85 has better resilience and almost zero creep that other Yonex strings do not have.
    Also, AOTBE the thinner the string the more power you will get. This is due to reduced air drag or resistance from the smaller diameter which will help you to hit harder and faster.
     
  4. CoolDoo6

    CoolDoo6 Regular Member

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    String at the right tension for the user produces the greatest repulsion.

    It is possible some strings are more elastic than others and produces increased repulsion for certain users, but reduced repulsion for other users.

    For people lacking effective strength/power they may find thinner strings more elastic, therefore more repulsive.

    For users with greater effective strength/power, strings with too much elasticity will reduce repulsion as the string is over stretched and absorbs too much impact energy. These users may compensat by increasing the tension to stiffen the string and lowering the elasticity. The drawback for this is that the string will be more easily stretched permanently (plastic transformation) leading to an early demise. The alternative solution for these users is that they could use a stiffer string (ti, kevlar coated) or use a string with lower elasticity per unit of impact-power such as thicker strings.

    My working theory on repulsion is that whenever the shuttle depresses the string bed by precisely X mm during an impact, maximum repulsion is achieved. If the depression is lesser or greater than X, repulsion is reduced. I believe X is a universal constant for all strings. I have no idea what X is, but it can be assumed to have come into being when maximum repulsion is experienced. There are 2 main factors that determin if X can be achieved by an impact. These are the string tension and the player's effective strength/power. The beauty of this theory is that it allows all strings to be repulsive, which is generally true in reality given the variety of strings people actually use and swear by for power. The theory also explains why people would need different tension depending on their effective strength/power in order to achieve X and maximum repulsion. Further more the theory accommodates the possibility of maximum repulsion for both high and low tension users.
     
  5. taneepak

    taneepak Regular Member

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    When comparing string A and string B, all other things must be equal. It is a fruitless journey to nowhere if other variables are introduced. For player X who wants to find out whether string A is more repulsive than string B, if all other things are being held equal, the thinner string will always be more repulsive at all tensions.
     
  6. CoolDoo6

    CoolDoo6 Regular Member

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    A trampoline may be repulsive to a thin man given the height it can achieve for him. But if a fat man were to jump on the same trampoline, it would no longer be so repulsive. Likewise for a string bed, if the user's power were to overwhelming the string, it would no longer be so repulsive. Thin or more elasic strings are more easily overwhelmed than thick and and less elastic string. So thin strings are not always more repulsive. The repulsion depends a great deal on the impact power.
     
  7. taneepak

    taneepak Regular Member

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    Have you tried using tennis strings for badminton to test out your line of reasoning?
     
  8. Heftiforex

    Heftiforex Regular Member

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    i dont think that some1 will make it to push 2 or even 3 strings through a badmintont grommet. especially higher end racktes tend to have smaller grommets. e.g. it is extremly tricky to get 2 strings of BG 65 through 1 single grommet of my armortec800. not that i do that, but i just tried once, to see if there is a real differnece in grommet-size.
     
  9. CoolDoo6

    CoolDoo6 Regular Member

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    Nope. But my theory would predict an extremely low tension, or extremely powerful arm, or a combination of both is needed on a very thick string in order to achieve the X impact depth.
     
  10. JoeyC.

    JoeyC. Regular Member

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    Thanks

    Thanks for all the replies guys!
     
  11. cooler

    cooler Regular Member

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    fresh string always have more repulsion
     
    #11 cooler, Mar 5, 2007
    Last edited: Mar 5, 2007
  12. jerby

    jerby Regular Member

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    isn't that step 2 after making a 'theory'? testing it? (though tennis strign would be a bit too much)

    personally, I think thinner string give more repulsion at equal tension...and I actually go úp in tension with thicker strings to compensate the loss of feel...to lower the tension on thick strings would mean you like a dead, soft rubbery stringbed...'different' repulsion that the "tiiinggg" of thin strings:eek:
     
  13. NoName1225

    NoName1225 Regular Member

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    wd-40, look at the thread string mods that i started. Apparently there's a debate on whether wd-40 will make it bouncier. But no one has tested it yet.
     
  14. j_e_thompson

    j_e_thompson Regular Member

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    You ever seen a fat man on a trampoline? Believe me, it's pretty repulsive :D

    (Sorry, couldn't resist. We have to put up with a trampoline class on the court next to us where we play)
     
  15. Boonbeng

    Boonbeng Regular Member

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    lol..........
     

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