tension loss

Discussion in 'Badminton Stringing Techniques & Tools' started by pompey, Aug 20, 2011.

  1. pompey

    pompey Regular Member

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    I'm experiencing a bit of a problem trying to string my racket to the tension I want and I'd be grateful for any advice.

    For my first attempt at stringing to 27lbs with nanogy98 I dialled in 26 mains and 28 crosses on my Pros Pro. I ended up with a tension that was quite a bit lower than I wanted - approx 24.

    This was not totally unexpected - I'm using two flying clamps and I can see them moving back perhaps 1 cm after unlocking the tension head, plus it's not possible to get them right up against the frame.

    So for my next attempt I just put in an extra 3lbs to compensate (29*31). It came out exactly as I wanted and I checked all the strings to make sure I hadn't created an nicks etc.

    The next day I went to play with it and during the warm up and the first part of the game I was really happy with the tension .......then it just seemed to drop dramatically over the rest of the game and I had to change rackets. I think it ended up at about 24lbs. What is even more baffling is the state of the strings. One of the centre crosses right in the middle between two mains (i.e. not where they intersect) was very notched/frayed and looks like its on the verge of snapping. Also other strings have some more minor fraying, but still far too much after 15-20 mins of play.

    I've heard that multifilament strings can lose tension quite quickly, but this seems excessively quick and the damage that has been caused is unacceptable. I can imagine that losing about 3lbs in 10 mins would place some stress on ther strings and maybe cause this damage.

    I didn't do any formal prestretching (i'm not sure of the correct technique) but i did take time to pull the string with the crank.

    I'm very confused and any help would be great - otherwise I can't string my racket :crying:
     
  2. anthemtwins

    anthemtwins Regular Member

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    Have you checked/calibrated your machine?
    This would maybe explain the first phenomenon of having to 'overtension' to achieve your desired results.
     
  3. Mark A

    Mark A Regular Member

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    ^Second on the calibration check.

    To pre-stretch a string, loop it around a (smooth) doorknob and pull it by hand until the "play" is removed. String stretches by a few percent and then becomes a lot more elastic - you'll "feel" it happen:).
     
  4. pompey

    pompey Regular Member

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    Cheers for the replies. I probably will calibrate it, although that isn't my main problem at the moment....it's the large drop in tension after 10 minutes of play and damage to the string. Surely this can't be normal? Has anyone else experienced this and what are the likely causes?
     
  5. kwun

    kwun Administrator

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    once the string is on the racket. the only way that can cause tension loss are:

    - the knot was poorly tied and slipped - this can be check easily. there is only so much that the knot can slip before it become undone.
    - the frame collapse - ie you broke your racket and the tension goes to 0. ;)
    - the string stretched over time.

    the first two can probably be eliminated easily and that leaves the last one. that's just the nature of the string itself and unfortunately one cannot do much other than doing some pre-stretching of the string during or before the stringing process.

    which Pro's Pro do you have?
     
  6. Brale90

    Brale90 Regular Member

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    I have also problems with tension lose. After stringing i "feel" the 26 -28 lbs.
    After 1 session ~ 24 lbs. So i restring every week.
    When i start with 22-24 lbs i dont lose tension.
    I have a pro pros pilot, working with yonex flying clambs and bg 66 and bg 68 t.

    My flying clambs damage the bg 66 a bit.

    I cant help you. I only can say that youre not the only new stringer with this problems.
     
  7. pompey

    pompey Regular Member

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    I have the Shuttle Express, but as you say once the stringing is done there are not many reasons why the tension should drop. My knots seem ok, maybe not expert, but they haven't slipped.

    Is there any way that my stringing technique could have caused this? Do I try different strings? Will prestretching cure all this?
    Unfortunately 24 lbs is no good to me - I need to get up to 27 or I'll have wasted my cash :eek:
     
  8. yan.v

    yan.v Regular Member

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    Prestretching will make a big difference depending on the string you use. It should be quite noticeable with the nanogy. Other than that, just use the recommended pattern (or at least do not use some funky pattern), make sure that your knots are tight enough (there is a thread here about how to tighten a knot properly, notably using starting clamps), straighten the mains/crosses after stringing and do not use the racket for at least a day after stringing.

    That is all I can think of relating to tension loss. Also note that the tension will always drop 1-3 lbs after the first 24 hours (there is also a thread about that, it's quite interesting if you can find it).
     
  9. kwun

    kwun Administrator

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    GrandMaster Pete uses a crank like the Pro Pro's pilot.

    what he does is he tensions twice. crank it once, slowly, wait for the tensioner to reach the desired tension, disengage. and then uncoil the crank, reengage the tensioner and then crank again. it makes the process much much slower but it works really well for him to get rid of the extra slack. this will have the same effect as pre-stretching, perhaps even much better than the manual hand pre-stretching.

    even so, with any string, even with pre-stretching, the string does lose tension. that's just a fact of life. we have done experiment and see that the tension loses gradually over the course of a day by 1lb or 2lbs, and then the first time one uses it, the tension go down another pound.

    as i said, that's just a fact of life.
     
  10. Fidget

    Fidget Regular Member

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    Notes from another novice:

    a) The double pull technique, as preached by PeteLSD, is slow but satisfyingly good for keeping consistent tension. However I don't assume that it replaces pre-stretching. There is a definite difference in the final result if I don't pre-stretch.

    b) The OP says that his knots don't slip ..... but does that also mean that there is no looseness between that perfect knot and where the last clamp is? A little lack of tautness in that last unclamped length of string has ruined an otherwise fastidious job for me in the past.
    (I don't fancy jamming a metal awl into grommets. I have tried a wooden skewer, but I dont think it really prevented any slippage.)

    c) Pompey, to what do you attribute the fraying of the centre crosses? One possible cause would be pulling those crosses through quickly whilst threading creating friction (although you'd think that would hurt the mains more). Or perhaps you are getting kinks/twists earlier on that are weakening the string ,but not becoming apparent until under tension and used for a few games. Only you would know what might be the cause there.

    Enjoying all the comments from the more experienced folks. :)
     
  11. LazyBuddy

    LazyBuddy Regular Member

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    If you use a crank machine, either pre-stretch or double pull will greatly reduce the tension loss. The extra fray means the string is damaged during the process, either by ultra fast pulling (cross), or the clamps are too tight, or have rough / sharp surface.
     
  12. Mark A

    Mark A Regular Member

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    Taking off from kwun, the slower you move the crank, the less tension falls off due to sag (but you have to compromise between tension fidelity and speed). You can do what I did and over-clock the crank 10% higher so the tension falls to the correct value by the time you clamp the string.

    However, once the crank locks out you should move as FAST as possible with the clamps - there's a couple of videos of a guy stringing some tennis rackets on a PeteLSD-style gamma, and he threads mains WHILE the crank is locked. This is a HUGE no-no: tension is falling off every second the crank is locked. Here's one (see 3.15 ish).
     
  13. Pete LSD

    Pete LSD Regular Member

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    Mark,

    The string loose tension whether the tensioner locked out or it was clamped already, because nothing is pulling it.
     
  14. Mark A

    Mark A Regular Member

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    ^I think a longer string under the same tension will sag more than a shorter one, so it's in our interest to get the clamps on ASAP - you'll see in my video that I also nudge the tension head forwards before pulling for the same reason:).
     
  15. Pete LSD

    Pete LSD Regular Member

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    (a) GrandMaster Fidget, what do you think of using weight plates to pre-stretch strings in the form of a drop-weight string stretching machine?

    (b) The safest way to reduce tension loss is to tension the very last bit of string. The distance between where the string is clamped and where it comes out of the grommet to form a knot is not substantially stretched. The OP should consider pulling that part with the help of a starting clamp with a string extension. I can post photos later of the procedure but I think Kwun and Tedski know what I am talking about.

     
    #15 Pete LSD, Aug 21, 2011
    Last edited: Aug 21, 2011
  16. Pete LSD

    Pete LSD Regular Member

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    There is a certain ratio that I keep to: for every one pull on the main except for the middle eight main strings that I do double pull, it is two pulls on the cross. Through experience and the nature of the Gamma 6004 machine, pulling twice on each main string and cross produces a slightly round frame. Of course, each stringer has his/her preference. Your mileage will vary :D.

    Engage and re-engage the tensioner is quite effective and a lot faster than putting the flying clamp to the strings and tension again.

     
    #16 Pete LSD, Aug 21, 2011
    Last edited: Aug 21, 2011
  17. Pete LSD

    Pete LSD Regular Member

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    Sure GrandMaster Mark, as long as we get good reasons and that is all that matters :)!

     
  18. Mark A

    Mark A Regular Member

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    ^We users of the mediaeval crank machines have to - or at least should - be super-OCD (unlike our lacadaisical constant-pull cousins). I'd give my left arm for a WISE, but at least when I use the crank I feel like a purist:D.

    I have seen diagrams of contraptions for pre-stretching string involving big heavy cylindrical weights - overkill, IMO, even for my raging OCD.
     
    #18 Mark A, Aug 21, 2011
    Last edited: Aug 21, 2011
  19. Fidget

    Fidget Regular Member

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    Thanks for the advice, Pete. :)
    However, as far as prestretch, I don't see why a cumbersome weight is any better than a doorknob. Please explain.
     
  20. Pete LSD

    Pete LSD Regular Member

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    Perhaps, the stretch would be more consistent than door knob or round staircase knob.

     

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