USRSA Ratings

Discussion in 'Strings' started by DrewRafter8, Oct 21, 2009.

  1. DrewRafter8

    DrewRafter8 Professional

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    When do the stiffness ratings come out? Once a year, or as strings are released? I'm wanting measurements on the Genesis stuff.
     
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  2. jim e

    jim e Hall of Fame

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    It will be published in the Jan. issue of RSI as that is a larger issue and more details can be printed.They usually send it out about the 3rd week of Dec. They use to put it out in Sept. issue, and this was the response emailed to me when I inquired!!
     
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  3. DrewRafter8

    DrewRafter8 Professional

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    Thanks! .
     
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  4. jim e

    jim e Hall of Fame

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  5. i suck at tennis

    i suck at tennis Rookie

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  6. scotus

    scotus Legend

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    Wonder why Weiss Cannon does not participate in this.
     
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  7. PED

    PED Legend

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    Jim, thank you very much :)

    It's funny how different the feel is when hitting with a string versus the number on a page. For instance, Bab Revenge in the 16g is rated at a stiffness of 302, the third firmest string but I felt like it played quite soft.
     
    Last edited: Dec 29, 2009
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  8. DrewRafter8

    DrewRafter8 Professional

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    In terms of a string being the same type, i.e. poly, nylon, gut, do the ratings always indicate that a lower number on the stiffness rating is better for joint health?
     
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  9. PED

    PED Legend

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    Supposedly so ;) I think you can use numbers for comparison across categories though: syn gut versus Poly for example.
     
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  10. davidahenry

    davidahenry Professional

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    Just received the January Issue of RSi yesterday. Here are the stiffness numbers on the Genesis strings I see listed...

    Spin X 17: 250 (lb/in.)
    Black Magic 17: 252
    Spin X 16: 258
    Black Magic 16: 261
    Spin X 17 (Silver): 265

    Hope this helps.

    Take care.

    DH
     
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  11. DrewRafter8

    DrewRafter8 Professional

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    I saw that on the link posted. 265 is nuts! Guess it goes to show that I don't have a clue when it comes to guessing what a string will measure based on feel....
     
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  12. raygo

    raygo Semi-Pro

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    #12
  13. samster

    samster Legend

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    #13
  14. Shangri La

    Shangri La Hall of Fame

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    This is good stuff!
     
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  15. stanfordtennis alum

    stanfordtennis alum Hall of Fame

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    thanks for the link jim...
     
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  16. BigT

    BigT Professional

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    According to this list:

    SPPP 1.18 is stiffer than SPPP 1.23
    Big Ace 1.25 is stiffer than Premier Ace 1.25

    You tell me if these numbers mean anything.
     
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  17. jim e

    jim e Hall of Fame

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    ...............................edit
     
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  18. old coach

    old coach Rookie

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    No surprise here. You all should read how the test has been performed and what kind of inaccuracy can occur in this data. This test probably the best under current technology available to USRSA, but it is not accurate. That why (maybe) some of manufactures of smaller string companies decide not to participate as lot of this information is simply misleading.
    Happy New Year to you all!
     
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  19. Greg Raven

    Greg Raven Semi-Pro

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    How do you know it's not accurate? That is, against what are you comparing?

    Also, are you saying that these alleged inaccuracies are somehow more pronounced in the testing results of strings from smaller companies, and only in an adverse way?

    I'm puzzled by your logic.
     
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  20. Kevo

    Kevo Hall of Fame

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    I'm not sure he meant inaccurate in a technical sense. I think he meant it doesn't correlate well with real world experience. (Old coach, correct me if I'm wrong please.)

    I've commented on this testing before, and I think it's useful for what it is, but not so useful if you don't pay close attention to what is actually being measured.

    My main complaint is that all the strings are tested at one tension, 62lbs. I only have a few customers that string that high, and only one who strings poly that high, and that is in a hybrid. This test doesn't really tell me much about the stiffness of the strings at lower tension. The same thing applies to tension loss.

    This is something that could be tested or at least considered on a sampling of strings with the current testing method. At least that would give some insight as to the potential merit of testing a range of tensions. There may be no merit at all, but we don't know that.

    Secondly, there is the interaction of the ball with the strings. That is, after all, what we feel. I don't think this test addresses that at all. Again, there may or may not be any significant merit to trying to test a balls impact with the string, but it's just a guess as to why sometimes the numbers don't seem to make sense with personal experience.

    In the end, the feel of hitting a tennis ball is probably quite subjective, so using the numbers strictly as a tool for making educated guesses for demo selections is probably the best way to think of it.
     
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  21. Greg Raven

    Greg Raven Semi-Pro

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    As to the "test tension," we did initially test at different starting tensions, and it turned out to generate cubic work for no additional data. Also, if you will note the test methodology and results therefrom, you will see that the stiffness is tested AFTER it has lost tension for 200 seconds. Most strings seem to work best between 40 pounds and 65 pounds, and this methodology ensures that most strings are within this window during the test.

    Not only is there interaction between the string and the ball, but there are string-to-string interactions in the stringbed. Of the two, the string-to-string interaction is more complex and, frankly, less linear. For the string-to-ball interaction, the stiffer the string, the more ball compression you get. The more compliant the string, the more string deflection you get. There is only a difference of a percentage point or two (IIRC) as you go up and down the scale. There can also be interactions with the grommets and frame characteristics.

    However, these non-string-to-ball interactions are extremely difficult to model, and that's assuming that you can consistently string a test racquet essentially identically from test to test, which is impossible at some levels.

    Therefore, we test a single string and generate two valid data points (well, three including diameter), rather than test a stringbed and wonder what the heck is actually being tested. This avoids the kind of confusion one sees when comparing -- for example -- ERT stringbed measurements against RDC measurements.
     
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  22. DrewRafter8

    DrewRafter8 Professional

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    So Greg, since you were on the testing team, I repeat my earlier question. Can we corollate a stiffer string from USRSA data to causing more stress on joints i.e. tennis elbow? Thanks!
     
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  23. Greg Raven

    Greg Raven Semi-Pro

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    There is some evidence that stiffer strings can contribute to tennis elbow. The same goes for stiffer racquets. However, you hardly ever see anyone using a sub 60 flex racquet with natural gut, and plenty of players use poly in 70 flex racquets with no problem. IMHO, poor stroke mechanics are much more likely to cause tennis elbow than stiff strings. YMMV.
     
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  24. scotus

    scotus Legend

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    Hello Greg Raven,

    Do you re-test older strings (i.e., the strings that remain in production for years) every year? Or do you re-publish the old result?

    Thank you.
     
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  25. JT_2eighty

    JT_2eighty Hall of Fame

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    The only evidence I've read about is that a more elastic string will absorb more shock because the ball sits on the strings just a bit longer than it will on a stiff stringbed, so then the assumption is that by absorbing more shock, a string like nat gut will be better for the arm/joints. Now, is the opposite true then that a stiff poly-type string by absorbing less shock will contribute/cause TE? I'll leave that to the scientists, but it seems the jury is still out, but for sure technique/mechanics are probably the #1 concern, but if you are playing in pain, it wouldn't hurt to use a more elastic string as well as work on form. Of course, there are also some who even have TE when using flexy-gut-filled sticks, so it all comes back to form.

    On another note, I use a PT280 (58 flex rating) with full gut, and all I have to say is it feels like butter out on the court. Sweet, scalpel-y butter.:)
     
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  26. Greg Raven

    Greg Raven Semi-Pro

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    No, we only add new strings.
     
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  27. blackfrido

    blackfrido Hall of Fame

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    Is there any comments about tension maintenance for Black Magic?
     
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  28. Nojoke

    Nojoke Rookie

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    those seem high considering how soft everyone says (myself included) black magic feels.
     
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  29. old coach

    old coach Rookie

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    ^^^^^^^^^^
    If it's feels soft, it's probably is soft. This data not to tell you, if the strings are soft or stiff. Same strings will feel and play differently in different rackets, different racket flex, different balance ........... and the last and most important a different player.
    Test been performed with a single piece of string, NOT in the string bed of the racket. Someone correct me if I'm wrong.
     
    Last edited: Jan 14, 2010
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