Could some strings behave differently as crosses than as mains?

Discussion in 'Strings' started by jaydog23, Jun 11, 2013.

  1. jaydog23

    jaydog23 Rookie

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    So I'm using a full bed of Solinco Tour Bite 18 in my Prestige Classic right now. I'm getting good spin. Just looking at the Tour Bite string, though, I feel like as a cross it provides very little spin. I mean, just look at it: the corners probably don't grab ball when they're vertical. I feel like the ALU Rough, however, would provide great spin potential as a cross string, due to its notches, if you will. Does this make sense to you? Anyone experimented with this? Thanks.
     
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  2. mlocke1322

    mlocke1322 Rookie

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    I'm sure strings can behave differently depending on crosses or mains. Lux 4G is trash to me in mains but I love it as a cross
     
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  3. ElevatorGuy

    ElevatorGuy New User

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    I've wondered about this too... like what if I put something Volkl Cyclone in the mains with ALU Rough in the crosses, would I get some insane amount of spin or something?
     
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  4. Muppet

    Muppet Hall of Fame

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    The benefit of using a shaped string as a cross is that there will be less surface friction at the intersections. The edges make less contact with the mains than a smooth cross would. The down side is that a shaped cross will wear into a soft main string faster.
     
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  5. ChicagoJack

    ChicagoJack Hall of Fame

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    Hi Jaydog,

    Your intuition is correct. It's pretty safe to say that ALL strings behave differently as crosses vs mains. Hard to know where to begin, so much information available on this, most of which can be found right here in our very own Tennis Warehouse University.

    The short, way too simplified answer, is that : 1. Surface hardness matters. Better to have soft mains and slick, hard crosses. Gut/Poly has the lowest inter-string friction on record. However, when you reverse the hybrid set up, Poly/Gut has among the highest. 2. Of the two types of friction, Ball to string friction is not such a big deal, matters only incrementally, and matters only if the mains are are moving. String to string friction turns out to be a much more important factor to spin production. I dredged up a few quotes and links fer ya that are right on topic, just in case you want to dig deeper. Regarding your intuition about the importance of ball to string friction in spin production, I think you are not alone in placing too much emphasis on that aspect. You could see the third quote and link for more on that.


    Quote 1: "It is interesting how materials behave differently individully and in combination. It is espcially interesting how a particular combination of a main and a cross can behave totally differently when the string types are reversed into the cross and the main. In this case you would assume that the adhesion forces are the same and the shape of the contacting surfaces are the same. So it seems that the relative deformation between main and cross is what matters in the differing movement between the strings for a hybrid and reverse hybrid. Though many combinations are possible a couple types of deformation seem likely as most important. If the cross is softer than the main, the main will sink into the cross. To initiate movement along the cross, the main will first have to climb a hill out of the valley it sits in, but also it will have to continually plow its way forward as it moves and sinks down the length of the cross. If the cross is a multifilament or multistrand string, it can also fray and break filaments. These can stick up as obstacles, hooks, or spikes that can slow movement over them. If the main is softer than the cross, it will deform over the cross such that it forms a slot or groove to move over the cross. That may actually facilitate movement, especially if the deformation causes a leakage of some oil, lubricant, etc. from inside the string." -- Sliding Friction And Spin, Crawford Lindsey, Dec 7, 2010


    Quote 2: "String-to-string friction is one of several equipment-related influences on spin production. The lower the friction (measured below by the coefficient of friction), the more the main strings will stretch, slide and snap back tangentially to the ball's motion across the stringbed, thereby creating spin-producing torque on the ball. Different materials and combinations of materials differ in inter-string slipperiness. String orientation also matters. The coefficient of friction can vary dramatically for any two strings in a hybrid setup depending on which string is the main and which the cross." -- Preface To String Friction Tool


    Quote 3: Friction is important to spin, but not in the sense that most people think it is. In the past, two assumptions were the foundation for the conventional wisdom that (1) a rough string surface creates more spin by increasing the string's bite, grab and push on the ball, and (2) that inter-string motion would lessen that grabbing and thus should be minimized. So, to gain maximum spin, the goal was to use a string with both a high ball-string friction and a high string-string friction to create a rigid surface parallel to the stringbed.

    As so formulated, both of these assumptions have proven incorrect. First, experiments show that for a tangentially noncompliant surface, the spin will be nearly the same for all magnitudes of string-ball friction for impact angles typical for tennis shots. For reasons explained below, both rough and smooth strings will produce the same spin on a laterally rigid surface. Second, recent experiments (Spin and Material, Spin and String Movement, Spin and String Pattern and String Snap-Back and Spin) have also demonstrated that sideways motion of the main strings during contact with the ball actually contributes to increasing spin. This sideways movement exerts a torque on the ball when it snaps back into position, thus causing topspin. Polyesters have been shown to add about 20% more spin than nylons. Polyesters can differ up to about 15% from each other in spin production while nylons might vary by 20% from each other. And the difference between the spiniest polyester and stickiest nylon is almost 50%. Virtually all this difference is attributable to the amount of torque supplied by the sideways movement and snap back of the main strings.

    The role of ball-string friction in this process is that it influences both the amount of lateral string movement and the torque the snap-back exerts on the ball (though the magnitude of its contribution is yet to be ascertained by experiment). It is here that ball-string friction contributes to the difference in spin performance between string models, but only if the strings move. Otherwise, ball-string friction produces about the same spin for every string. And whether the strings move or not depends on the static and sliding friction between strings.
    -- Static Friction and Spin, Crawford Lindsey

    Jack
     
    Last edited: Jun 14, 2013
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  6. jaydog23

    jaydog23 Rookie

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    Thanks for the thoughts on this and the other threads where I'm trying to pick up some knowledge.
     
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  7. corbind

    corbind Professional

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    That is some good reading.
     
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