RacquetTune way off?

Discussion in 'Strings' started by JTJet, Feb 6, 2013.

  1. jmnk

    jmnk Professional

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    Honestly - I still do not get your point. RSI data shows that an individual strand of a tennis string will lose X amount of tension (what exactly X is does not really matter). You are saying that does not match your experience. And you are saying that somehow data showing tension loss of an individual string is somewhat not applicable to the tension loss of a full bed. Why isn't it? Are you suggesting that the strings in a full bed lose tension somewhat differently than if they were completely separate?
    BTW - there are already a pretty good threads on such tension loss topic, with empirical data here:
    http://tt.tennis-warehouse.com/showthread.php?t=397033
    and here;
    http://tt.tennis-warehouse.com/showthread.php?t=398516
     
    #51
  2. Buford T Justice

    Buford T Justice Semi-Pro

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    Thanks for posting those....great info there.

    I've been tracking two frames with RT and they seem to follow the same trend. There is a very definite big drop that occurs very early on, then the tension kinda hangs out there with small steps downward with each play session.

    In fact, I've been able to find the sweet spot with the app(where I find the stringbed the most playable) and can now guesstimate the initial stringing tension needed to have the stringbed stay in the desired tension range the longest. In my case, I believe the best initial tension with the Gosen Polylon will be ~65 lb.

    IMO, for $1.99, this app is a great tool.
     
    #52
  3. mikeler

    mikeler G.O.A.T.

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    I think he is saying that the RSI readings should underestimate tension loss not overestimate them.
     
    #53
  4. Centerforward71

    Centerforward71 Rookie

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    I'm not suggesting it I'm telling you they do.
     
    #54
  5. jmnk

    jmnk Professional

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    Would you care to elaborate? Provide some data? Measurements? Papers by someone that run some experiments? Cite some physics phenomena that would explain how a string is aware that it is in a full bed so it 'knows' to behave differently?
     
    #55
  6. Centerforward71

    Centerforward71 Rookie

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    In being so busy trying to discredit what I'm saying you have missed all the data, testing, phenomenon etc etc etc that you ask me to find for you......

    It's right n the very table you so adamantly pointed to from RSI, duuhhhh. If those numbers versus the ones we get on full beds isn't enough proof of this then sorry I got none other to offer you.

    The point is the full bed tension is different than single strand therefore making those numbers deceiving. Is that clearer ....

    Physics and some scientific common sense will tell you that a string that is on its own versus one that is weaved between many other will lose more tension and more rapidly because of the fact that it is being pulled independently versus pulled and then supported by other points along its length.

    I am not gonna go further and argue with you. If you disagree then continue doing so its ok ill sleep just fine. And also go ahead believing that your full bed going to lose tension at the rates stated in the RSI table and string accordingly and suit yourself to your own scientific conclusion.
     
    #56
  7. jmnk

    jmnk Professional

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    In short - you cannot provide any data, or explanation of what you believe is true. Fine with me.

    Now, when you happen to find more time - could you at least explain what a 'full bed tension' is? I know what 'string bed stiffness' is - is that what you mean?

    Finally - I'm not trying to discredit you. You stated that RSI data is wrong because you see different results. All I've asked is how you have measured your tension. I was hoping that perhaps indeed you were right, and by replicating what you did I could try and see for myself.
     
    Last edited: Feb 10, 2013
    #57
  8. mikeler

    mikeler G.O.A.T.

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    The RSI tables tend to overestimate the amount of tension loss we are experiencing using RacquetTune's measurements. Since those RSI measurements are only taken with 5 strikes, it would seem like our RacquetTune measurements should show greater tension loss than the RSI test. I'm still wondering if the title in the RSI title should be tension loss by percent and not pounds.
     
    #58
  9. Centerforward71

    Centerforward71 Rookie

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    I provided you data with my own use of Genesis Twisted razor over the poeriod of about a year, the data compared my stringbed stiffness/tension whatever you want to call it versus the single strand RSI table. Again if thats enough data to give you I dont know what data you want me to give you. I used a string for a year and tested it over that whole year on about 20-30 string jobs of my personal racquets. Does that not qualify as testing and data that you are asking me to give you ? If not then your right I dont have the Theory, Hypothesis, Testing and Conclusion of a scientific method to provide you.

    I realize we are comparing Apples with SORT OF Apples but there is a correlation difference and its the point I have trying to make to you here. That the data of RSI not that its false but that the portion of tension loss as a reference is not accurate because they themselves are measuring a single string hit 5 times which is WAY different than a weave of the same under the same conditions.

    Perhaps I should have said that the data is not truly applicable if taken at face value. I am not saying that the data is WRONG AS TAKEN but its WRONG as applied. Again I am sure you are trying to take some knowledge here rather than argue I would hope. So if what I am trying to say does not agree with you then thats fine state your case and point and it will be taken for myself and other to decipher if they agree.

    Let me again state my point to you and whoever reads this.

    Do not take these numbers at face value for determining tension loss possibilities or you WILL be misled because of the fact of all I have mentioned in the previous post and specifically the difference in the way a string will react at tension X in a weave of itself or all by itself can have a large varians "as shown by my testing and experience".
     
    #59
  10. Centerforward71

    Centerforward71 Rookie

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    Just trying to make the point that the numbers taken of this single strand can have large variances and may not even agree in overall terms with that taken from a full bed. I appreciate what RSI tries to do here but I think this can me misleading for stringers and players both. I beleive full bed testing should be a much better value.

    Something I dont mention is that The same full bed, same string, but different racquet and different pattern can also have an appreicable variable difference. POINT AND CASE and tested is my testing of the Wilson steam 99S over a months time, WOW this racquet and pattern lose tension about twice as rapid as some 16x19 and even more than 18x20. This also further proves and is further testing of how full bed reacts different than the RSI numbers as my friend JLNK asks me to give data.
     
    #60
  11. Buford T Justice

    Buford T Justice Semi-Pro

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    It sounds like the best correlation to make is that the RSI data can be used to demonstrate the differences in how various strings lose tension compared to each other, rather than trying to use those numbers as absolutes as to what should be seen (numerically) in a given frame.
     
    #61
  12. mikeler

    mikeler G.O.A.T.

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    Interesting about the Steam tension loss.
     
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  13. JT_2eighty

    JT_2eighty Hall of Fame

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    Agreed. It's not the specific numbers that matter when looking at RSI or TWU data, but comparisons and relative differences or trends between strings can be better understood with the accompanying data found at RSI and TWU.

    For instance, as a whole, Natural gut always have the lowest tension loss numbers and stiffness, and are all fairly close together. Then you have synthetics, multis, co-poly and finally kevlar; each group increasing in stiffness and tension loss, respectively and in most cases (the occasional stiff multi or soft poly or whatever can be seen as well). There are other trends one can browse, like stiffness, and then all sorts of other relationships on TWU, like dwell time, energy return, and so on.

    I agree the tension loss stats are the least useful on these two databases, although they do generally show that natural gut, for instance, has better tension hold than poly. But whether "string X loses 17 pounds" versus "string Y loses 18 pounds", that hardly will matter on court. I also agree that a StringBed of interwoven strings behaves way differently than a single strand, which applies also to stiffness, dwell time, etc. The racquet you put a string in also changes the way a string behaves. There are strings I love in the dense, flexy PT280 but can't stand in the open, stiffer YTPP. Yet both of the racquets I have setup to the same weight and balance, swingweight, etc. Strings also remain playable longer in the denser, flexy racquet; and breaking much faster in the open pattern.

    Getting too fixated on the exact pound or percentage loss of a string isn't that important. The importance in the RSI and TWU tables, to me at least, is to see how various strings compare to each other. This can give people a good starting point in trying out a new string or finding something to compare to their favorite string. It's definitely not the 'end all, be all' but can be a useful guide.


    In the end, on court testing will always be the best guide because only then can one Experience the characteristics of a string or racquet or whatever; and while subject to subjectivity or other things that can't be displayed on a graph, experiencing different strings and racquet combos tend to be very subjective; one man's trash is another's treasure and that does go a long way on the tennis court.
     
    Last edited: Feb 11, 2013
    #63
  14. ultradr

    ultradr Hall of Fame

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    By the way, also note that human sensory systems (what we actually feel)
    are often NOT linear. In fact, quadratic or logarithmic in a lot of cases.

    Just a food for thought.:)
     
    #64
  15. jimbo333

    jimbo333 Hall of Fame

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    Really interesting thread to read, great stuff!
     
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  16. mlocke1322

    mlocke1322 Rookie

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    My racquettune has gotten so screwed up. Every time I try to input a hybrid, it tells me that I haven't set all of the parameters and that the string factor is "0" when it clearly has a calculated number for the string factor. Anybody having this? I've deleted and re-installed it several times. Suggestions?
     
    #66
  17. Dags

    Dags Professional

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    I reported that as a bug in an earlier version, and Sten fixed it. Just to check - you are running the latest release?
     
    #67
  18. mlocke1322

    mlocke1322 Rookie

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    Yep. I have done all updates and have even deleted, reinstalled and checked for updates a few times. I'll report it and see if I can get it fixed
     
    #68
  19. Dags

    Dags Professional

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    You're not going mad: mine is broken too. Must have been that latest release that did it!
     
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