Tension Loss

Discussion in 'Stringing Techniques / Stringing Machines' started by Roger Wawrinka, Feb 3, 2014.

  1. Roger Wawrinka

    Roger Wawrinka Professional

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    If you were to string a racquet then not use it for a couple days rather then use it that same day, does the tension decrease enough to notice a difference?
     
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  2. Irvin

    Irvin G.O.A.T.

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    I recently got a used Star 5 stringer. When set @50# the Star 5 pull at 50.4# and the Wise pull at 50.1#. Last night I strung one of my rackets at @50# on the Star 5, but no measurement made. This morning I strung the other on my 6004 / Wise @50# and when I pinged them they were both the same but the one strung on the Star 5 was +0.3# higher. Tonight the ping sounds are different so I measured again. The one strung on the Start 5 is still almost the same 48.4 and the one strung on the Wise has dropped 3# to 45.1.
     
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  3. jim e

    jim e Hall of Fame

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    The USRSA tests strings routinely.
    Although tension cannot be measure once it is strung you can measure SBS.
    With their string tests they measure string bed stiffness (SBS) with an RDC machine. Their control string is Prince Syn. Gut original 16g. 60 lbs.
    The SBS is measured immediately after stringing and again 24 hours later no hitting and that reference string has a 9% loss in SBS. Many strings compare to this contol string as this is a reference as each string and type are different. Some are a little less, and some are more as depends on string and gauge.

    Will you notice, I rather doubt it.
     
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  4. Roger Wawrinka

    Roger Wawrinka Professional

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    Thanks guys, just as an add on does it matter what string? My usual setup is lux. alu power at 55/54.
     
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  5. pmata814

    pmata814 Professional

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    When I string my racquet with my WISE I check the tension with the Racquetune app. Strangely it usually reads 3-4 lbs higher than what I strung at. I don't trust that number much but I do feel that it is good to track relative tension loss. Anyways, my racquet loses 3-4 lbs overnight of just sitting in my bag.
     
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  6. mad dog1

    mad dog1 Legend

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    what racquet and what string or strings? may or may not be strange at all depending on the racquet and/or string.
     
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  7. mad dog1

    mad dog1 Legend

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    remember that the Star 5 overshoots the reference tension so it results in a stiffer stringbed. the overshoot serves a bit like a prestretch so the stringbed loses less tension over time.
     
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  8. pmata814

    pmata814 Professional

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    Its happened on my ig radical pro with ogsheep17 and with solinco tour bite17. Also with my pro staff 95 w/ head pps 17 And all 3 times it reads higher fresh off the stringing machine than the tension i strung it at. However, by the next day it's settled/stretched back down to where i strung it at. (Again, this is all according to racquettune) i only use racquettune to keep track of tension loss. I suspect it's pretty accurate for that.
     
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  9. mad dog1

    mad dog1 Legend

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    for those strings and racquets, what you're describing is strange. did you use the correct string factor for racquettune?
     
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  10. Irvin

    Irvin G.O.A.T.

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    I have head the Star 5 overshoots but I don't see that. I put a digital scale on the Star 5 when set at 50 it did not overshoot like I've heard. But I am seeing a lot less tension loss from Star 5 strung racket compared to a Wise strung racket. I'm think is has a lot to do with the very small drawback on the Star 5.
     
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  11. mad dog1

    mad dog1 Legend

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    it overshoots at the peak and then settles back down very quickly to the reference tension. it's instantaneous so it's a bit hard to see and measure. i've observed my sensor overshooting ~2#s on poly and ~5#s on syn gut/multi/gut. the limited drawback is certainly a factor as well.

    how do you like the star 5 vs the gamma?
     
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  12. jmnk

    jmnk Professional

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    Just out of curiosity - how do you measure the tension of the strings on the strung racket?
     
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  13. Irvin

    Irvin G.O.A.T.

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    It is a toss up. Some features I like better on the Gamma and some are better on the Star 5. Mounting frames is much faster and easier on the Gamma but frame distortion (total length) is almost non-existent on the Star 5. All features considered I like the Star 5 the best.
     
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  14. Joonas

    Joonas Semi-Pro

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    In my world drawback should lead to instant tension loss = lower SBS.

    Pre stretching, overshooting or pulling longer should lead to slower tension loss as elasticity of the string is being pulled out during stringing and less elasticity is left to lead to loss in tension.

    Congrats on Star5! I have been looking into Sensor but trying to talk rationale to my self and stick to my current machine. Enjoy it!
     
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  15. pmata814

    pmata814 Professional

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    I don't ever mess with string factor. Don't know what it is. I just select the string from the drop down menu when available. If not i just put if it's poly, synthetic gut, etc. and the gauge.
     
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  16. Irvin

    Irvin G.O.A.T.

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    You made me start thinking again. I had previously asked the Babolat tech if the Star 5 had over and he said no. I tested it before with Kevlar string and could not see overshoot but with different strings the Star 5 pulls differently. So I used a stretchy SG string to test at 58# and it pulled at 59.x but just for an instant. Too fast for me to catch the tenths digit then settled on 58-57.9. So there is a little bit of overshoot depending on the string but for no more than one second if that.
     
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  17. mad dog1

    mad dog1 Legend

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    yes, this is what i observed as well. it's possible the have improved the tension head to minimize the overshoot over time. my sensor is an older one from the first year they were released.
     
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  18. mad dog1

    mad dog1 Legend

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    if you don't use the correct gauge, the racquettune reading will look odd and you will experience what you've seen.
     
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  19. Irvin

    Irvin G.O.A.T.

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    I used RacquetTune. If you set up the string factor properly it comes out put pretty close to set tension I use to string the racket. I believe for what you pay for the application it is pretty close if you use it correctly. The frequency of a string is dependent upon the composition of the string, the diameter, tension, and length. If you set it up so the string is close enough to the microphone and you get the length and tension correct I think you can get a string factor that is very close.

    Then you have to set up your racket. The area of the frame number of mains and cross and the string used all make slight changes in the overall frequency of the stringbed. Is it "Dead on Balls Accurate?" I doubt it but it is close enough and the main that is am doing here is measuring tension loss of the stringbed the main topic of this post. I have yet to hit with the rackets because of the weather here but if I can tell the difference I will let you guys know. I think I will be able to. The racket strung on the *5 if at 48.1# (~4% loss) while the racket strung with the Wise is 44.3 (~11% loss.) But I attribute the differences in tension not to the tensioners but the clamps and support functions of the Gamma and Babolat machines.
     
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  20. Irvin

    Irvin G.O.A.T.

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    ^^+1 - As they say garbage in garbage out but if pmata814 is only looking for relative tension loss he should be ok he just needs to be ignoring the number.
     
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  21. pmata814

    pmata814 Professional

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    Im inputting the correct gauge. That im certain of. And ofcourse i fill in the correct pattern of the racquet. String factor i just use what racquet tune fills in. Is there a way to determine the correct string factor on our own?
     
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  22. Irvin

    Irvin G.O.A.T.

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    Absolutely RACQUET & STRING page top center select Add. On the ADD A STRING page select the > symbol to the right of Measure the string factor. You should be good to go from there.
     
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  23. pmata814

    pmata814 Professional

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    Thanks. I looked into it and it sounds like hassle. I'll just continue using it for tracking relative tension loss. :)
     
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  24. Joonas

    Joonas Semi-Pro

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    I have both Racquet Tune and ERT300.

    It seems to me that string factor in Racquet Tune plays impotent role as some strings (for example Yonex Poly Tour) give as a default poly 1.25 setting DT values quite near to the ERT300. Then again some other strings give DT values that are much higher than ERT300 reading. Also many times Racquet Tune gives higher drop in tension over time than ERT300.

    I have not played around with string factors. I would assume that exact values should return quite universal values on DTs. Overall Racquet Tune DT values seem to be higher to ones of ERT300.

    I use Racquet Tune to store my string jobs and keep track on tension loss over time.
     
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  25. ProStringing

    ProStringing Rookie

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    Overshooting reference tension

    Regarding Babolat machines and overshooting reference tension, Albert Lee has investigated this issue very thoroughly.

    This is explained comprehensively in this post, and in this entire thread.

    This overshooting does not register on the tension display on the machine, but instead requires laboratory grade equipment to recognize.

    Hope this can be of help,

    ProStringing
     
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  26. Joonas

    Joonas Semi-Pro

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    ^^4 ERT DT points up is a lot. I would believe that this is depending on the string type as well.

    But again for me this looks like the prime reason for slower tension loss on Star5 strung racquets Irvin was facing.

    Racket distortion and clamp slip should have an immediate effect on string bed stiffness - not for the tension loss.
     
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  27. Irvin

    Irvin G.O.A.T.

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    Not sure what you're getting at here. I think the *5 does have some overshoot but how much and for how long I'm not sure. Babolat says it doesn't have overshoot and it's possible that issue has been corrected. I see some peak but only a pound for a second at the most. If it is just a short peak for an instant it wouldn't be much different that hitting a ball.
     
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  28. Joonas

    Joonas Semi-Pro

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    Irvin, let me clarify.

    If your clamps have drawback or slip then string bed won't come as tight as it would with lesser drawback. But this effect is in your hands immediately after stringing. It has no impact on tension loss afterwards.

    If the racquet mount allows frame distortion which is the racquet gets shorter it will have similar effect on immediate overall string bed stiffness. The frame gives in to the mains tension and crosses can not make it up due to the friction. So again your mains end up being looser. And also this will not have an effect to the tension loss after racquet is taken out of the stringer.

    In my experience long pull time or pre stretching (overshooting) takes out the the "elastic headroom" of the string and thus less string elongation will take place after racquet is strung. This is slower tension loss isn't it?

    I don't see Star5 or Sensor overshooting as any problem. It is just the characterstic of those machines.

    I have seen and taken measurements of racquet distortion during stringing. And some expensive machines are not so good in that. Babolats should be on better side. But again the effect of frame distortion is immediate and is visible straight after stringing. The string bed is looser. But this will not affect the tension loss over time.

    You can try out how much your racquet mount gives in during stringing quite easily.
    1. Mount the racquet and take exact width of the empty frame
    2. String all the mains at 60lbs and measure the width again
    3. If width has increased less than 0.2in (5.1mm) the you have quite good racquet mounting.

    I did this test to my Stringway ML100 and when using the normal mount (not Babolat retainer) the width increase was about 3mm. This is one reason why I dropped the idea of going to the Alpha Ghost. The Sensor is still in my mind but as said before SW is doing the job well for me :)
     
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  29. Irvin

    Irvin G.O.A.T.

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    Thanks Joonas I see what your saying now. I have not measured the distortion of the frames with just the mains strung in the *5 yet but I will. On the Gamma machine after stringing the mains only the center mains are what I would call loose and I could tell there was a difference in tension. But after stringing the cross the racket length was correct so tensioning the cross did stretch the racket back out.

    After stringing the mains only on the *5 the mains are not loose (slightly maybe but not like the Gamma.) So when tensioning the cross they are being pull through a more uniform set of mains and I think the cross string tension will be more uniform. I could be wrong but if the tension is more uniform it seems to me the tension loss over time will be less.
     
    Last edited: Feb 6, 2014
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  30. Joonas

    Joonas Semi-Pro

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    ^^This is how it should be with Star5 compared to Gamma.
     
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  31. Irvin

    Irvin G.O.A.T.

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    Finally got around to hitting with my rackets today. The *5 strung racket was @47.9# after hitting and the Gamma strung racket was @44.3# a difference of 3.6#. I liked the *5 strung racket much better as the other one felt like I was playing with dead balls. If the tensions were the same now in both frames I'm sure I couldn't tell the difference.
     
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  32. Joonas

    Joonas Semi-Pro

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    Irvin, I think that Star5 little overshooting of tension comes handy in stringing crosses. We know that to overcome friction you need little extra force. So what you thought about cross tension makes sense.
     
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  33. stoneage

    stoneage Rookie

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    "The ultimate tension loss measurement thread"
    http://tt.tennis-warehouse.com/showthread.php?t=398516

    ___________________________________________________________
    RacquetTune and [URL="http://www.appmaker.se/swingTool”]SwingTool[/URL] racquet apps for iOS (and soon Android).
     
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  34. Imago

    Imago Semi-Pro

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    If you tight hard any frame will be distorted because the side towers are outside and the top and bottom towers are inside - the only possible outcome of tightening them is the elongation of the racket frame. In order for it to become shorter, the side towers have to be inside and the top/bottom towers outside - and this is clearly not the case.

    When you string the mains the geometry of the frame doesn't change; when you string the crosses, the frame head always get longer, so often you may end up with the towers totally loosened at the end.

    Following this universal mechanical distortion rule, immediately after dismounting the racket, we should expect the mains getting overtensioned and the crosses undertensioned (mainly because of the 3-5 kg drawback, which is totally ignored by almost all professional stringers around here - I wonder why!).

    As the frame tends to restitute, i.e, to get its normal geometry, depending on the individual rate/speed of restitution, the tension of the mains will be expected to drop down in the restitution time, while that of the crosses - to come up. After that, it all depends on the quality of strings and intensity of play.

    BTW, using Racquet Tune to gauge the tension is a joke, because it gives you the combined tension, not the tension of any main or cross.

    Even the most expensive automatic stringer serves only as a reference tool when tension is concerned and correspondingly cannot replace the experience and compensatory practices/habits of the human behind it.

    Human factor is the most important in the stringing, machine can only make the stringing process shorter, nothing more.
     
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  35. mad dog1

    mad dog1 Legend

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    Stop bashing a great product. RacquetTune works quite well assuming you know how to use it. If you want to know what's a joke, you only need to look in the mirror. No experienced, knowledgeable, and proficient stringer would ever do something as ridiculous as you've done in your picture...

    [​IMG]

    from your post...

    http://tt.tennis-warehouse.com/showpost.php?p=7790946&postcount=31

    I imagine it could be complicated to figure out how to use a computer application seeing as you have trouble figuring out how to use a basic mechnical stringing machine. ;)
     
    Last edited: Apr 27, 2014
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  36. GlenK

    GlenK Professional

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    Was going to send you some feedback today but since I saw you here.. Latest update on RT is awesome. Love the setting for saving units and you corrected the "saving" issue I was having. Great tool and great job and I appreciate your efforts on all the apps!!!
     
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