Poly really more powerfull or only heavier?

Discussion in 'Strings' started by Veninga, Oct 27, 2012.

  1. Veninga

    Veninga Rookie

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    Guys,

    Reading about poly's, I noticed 2 main observations:
    - poly has more power
    - poly is heavier. up to 5 grams.

    Almost every racket (with a SW below 340) will definitely feel an increase of power if it would get an additional 5 grams in the hoop.

    So is poly really more powerfull or is just a effect of the extra swingweight?
     
    #1
  2. realplayer

    realplayer Semi-Pro

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    Poly is not more powerful.
     
    #2
  3. MikeHitsHard93

    MikeHitsHard93 Hall of Fame

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    Poly is not more powerful than, per say, a multi.

    Also, there is not a big enough difference in weight between strings to really increase or decrease swing weight
     
    #3
  4. ChicagoJack

    ChicagoJack Hall of Fame

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    Veniga -

    I don't know what you've been reading but string bed power is about conserving the energy of the ball at impact.

    (Long Answer For Deeper Understanding)

    - Balls Are 45% Efficient : Softer strings, and or lower tensions are more powerful because the ball compresses less, and loses less energy. The rules of tennis dictate that when you drop a tennis ball from a height of 100 inches onto solid concrete it must bounce to a height of 53-58 inches. If the ball bounced back to 100 inches high, then the ball would have been 100% efficient at preserving the impact energy. This bounce height of 55 inches or so, tells you that tennis balls are designed to convert 45% of the collision energy to friction, heat and other things not very useful to a tennis player.

    - String Beds Are 95% Efficient : So, what we want for maximum ball velocity is to have the ball squash less, because the ball sucks at converting impact energy into outgoing velocity. String however, is 95% efficient. We know this from measuring the bounce heights of things that don't squash, like wooden bocci balls. By the way, this 95% efficiency, explains why changing string type, and changing tension makes so little difference in ball velocity. There just isn't much room for improvement! Now let's put strings and balls together, make them collide. When one drops a tennis ball onto on clamped racquet it will bounce to a height between 75-80 inches. What this tells you is that the string stored up a little energy when it deformed like a trampoline, the ball squashed less, and the string bed returned some of the energy to outgoing velocity when it regained shape. That is exactly why the following statements are true:

    (Short Answer)

    The most powerful strings are the softest, and the most elastic. The difference in measurable ball speeds is amazingly slight, there is a bit of overlap with some of the string categories if you ranked them all out in order from softest to stiffest, but in general there is no doubt or debate at all about this. Gut is the most powerful, and Kevlar the least. Poly ranks #3.

    1. Gut (83-124 lbs in.)
    2. Nylon Mulitfiber and Mulitfiber Blends ie : Nylon/Zyex, Nylon/Polyolefin, Nylon/Polyurethane (135-231 lbs in.)
    3. Polyester (187-302 lbs .in)
    4. Kevlar (508-981 lbs. in)

    More String Basics:

    - Lower string tensions generate more power
    - Higher string tensions generate more ball control
    - A longer string (or string plane area) produces more power.
    - Decreased string density (fewer strings) generates more power.
    - Thinner string generates more power.
    - More elastic strings generate more power.
    - Softer strings, or strings with a softer coating, tend to vibrate less.
    - Thinner strings tend to produce more spin.
    - Increased string density (more strings) generates more control.
    - http://www.tennis-warehouse.com/LC/BasicFacts.html

    -Jack
     
    Last edited: Oct 29, 2012
    #4
  5. Veninga

    Veninga Rookie

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    thanks guys, I was already wondering if these assumptions (by many on this forum) were right, but not.

    should be sticky, the former posts.

    thanks.
     
    #5
  6. fortun8son

    fortun8son Hall of Fame

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    Also, don't go by those 'performance' graphs you see on the string packs.
    I had a senor citizen client yesterday that thought Luxilon Adrenaline would be a good replacement for the Wilson NXT that was strung too tight in his Hyper Sledge Hammer based on Lux's self-rating!

    Come to think of it. He may have liked the Adrenaline strung at 35.
    Naah, he'd leave it in for two years!...BB Ace, maybe. :)
     
    Last edited: Oct 30, 2012
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  7. pvaudio

    pvaudio Legend

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    The reason that people consider poly to be powerful is because of its lack of feel. As said, ball speeds are fairly similar, but with natural gut, you get an immense amount of feedback when you stroke the ball whereas with poly, you really only get feedback about spin. That translates into balls spraying about if you have not enough RHS to benefit from poly, and therefore, you conclude that the string is too overpowered. There is no polyester string on the market which returns the same energy to the ball as natural gut. There simply can't be, as that's exactly the reason why poly was invented: lower power = use higher swing speeds to create more spin and keep the ball in play.
     
    #7
  8. UCSF2012

    UCSF2012 Hall of Fame

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    It all depends on the dwell time, how long the ball sits on the stringbed. At a given tension, poly is much lower power than syn gut, because syn gut is stretchy and the ball sits on the strings so much longer on impact. Adjust the poly (lower tension) and the ball can sit just as long. At which point, you get serious power.
     
    #8
  9. pvaudio

    pvaudio Legend

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    ^^^This is not true, "dwell time" is a sensation. I promise you that there is not a significant variation in the amount of time the ball sits on tennis strings. The stiffer the stringbed, the more deformation of the ball, and the more compliant, the greater the deformation of the stringbed. It evens out.
     
    #9
  10. UCSF2012

    UCSF2012 Hall of Fame

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    Spare us your made-up physics on this one, will ya? I seriously doubt you can detect the difference of 100 ms vs 120ms or so.

    "Dwell time" is time.
     
    Last edited: Oct 30, 2012
    #10

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