Adding weight to the handle or buttcap?

Discussion in 'Racquets' started by mrravioli, Aug 15, 2014.

  1. mrravioli

    mrravioli Rookie

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    How does add weight to the handle or buttcap affect the maneuverability of a racquet?

    Theoretically, it does make the racquet more head-light but would still add to the swing-weight right? Could a higher sw with more hl benefit or hurt the maneuverability?
     
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  2. Irvin

    Irvin G.O.A.T.

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    Adding weight farther down on the racket makes it more head light and more maneuverable. Adding weight does not always increase SW but more often than not it will the smaller the weight and the lower the weight the smaller increase you will have. It is possible to add weight and lower the swingweight.
     
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  3. SpinToWin

    SpinToWin G.O.A.T.

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    Nope nope nope

    It is NOT possible to lower swingweight by adding weight.
     
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  4. LeeD

    LeeD Bionic Poster

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    "PERCEIVED swing weight".....
    Every sword has a huge counterbalance at the end of the handle. The actual SW is the same as without, but with the pommel, the sword is quicker and easier to swing.
     
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  5. morten

    morten Hall of Fame

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    I actually found the stability got worse as i added weight at buttcap...
     
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  6. LeeD

    LeeD Bionic Poster

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    "too easy to swing" leads to variances in the actual swingpath and timing.
    You need TIME and lots of practice to get used to the new balance, and in the end, since tennis racket's are actually quite lightweight, it's a PERSONAL PREFERENCE choice.
     
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  7. TimothyO

    TimothyO Hall of Fame

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    Adding weight to the butt cap and handle does NOT necessarily make the frame more "maneuverable". In fact, adding weight ANYWHERE on the frame decreases its overall agility and increases its inherent power and stability. If adding weight at the butt cap made the frame more maneuverable then you could simply add 10 pounds there and have the most maneuverable frame in the world. Obviously, it doesn't work that way.

    The key is to understand how adding weight in the butt cap/handle effects YOUR effectiveness with the frame.

    Adding weight in the butt cap/handle changes the frame's balance point. That changes the relationship between tip and butt cap during a full swing. That relationship is also driven by your arm length and weight, the presence of a wrist sweat band, etc.

    If your frame is properly balanced for YOU at a given static weight and SW then on a full swing or serve the racquet will naturally make clean, solid contact with the ball. If the frame is out of balance then either the head or the handle will get too far ahead or behind. You'll actually feel a wobble in the motion and might unconsciously break your swing to adjust or use excessive wrist action to muscle the head to clean contact.

    So adding weight to the handle is NOT about making the frame "maneuverable". It's primarily about making it "smoother" during a natural swing to contact.

    The challenge is that adding weight to the butt cap and handle also increases the total mass that your core/shoulder/elbow/wrist needs to accelerate to contact. There's no way around it. Add a gram to the butt cap and you need to accelerate that additional gram when swinging.

    So sometimes you need to REMOVE weight from the handle to achieve a proper balance for your physique relative to the frame's total static weight and SW. Or you might need to remove weight simply because the total static weight is too high for you and you don't want to remove weight from the business end of the frame.

    Remember too that Swingweight is measured from a point 10cm from the butt cap. You might hit a slice-like volley using that point as a center of rotation but in general we hit from our core. That center of rotation is far beyond the butt cap's 10cm point used in SW calculation. Take SW with a full shaker of salt and consider it ONLY in the context of other specs.

    So when thinking about a frame's balance (HL or HH) and whether or not to add mass to the butt and handle do NOT get trapped into thinking that simply adding more mass = more maneuverability. It doesn't.

    Instead try to feel whether or not the frame's swing to contact feels smooth or wobbly. Try to feel if you find yourself breaking your swing to muscle the frame into clean contact. Here's a good approach when looking at frame mods:

    1. understand how much total static mass you can wield in light of your physique and technique

    2. based on the frame and string's overall power level (which is NOT the same thing as SW) see if you need to add mass to the stock head for stability, plow, and power appropriate to your game and level of opponents (facing 30 mph dinks has different requirements from 120mph serves).

    3. tweak the frame's balance by adding mass to the handle until you're getting a smooth, clean, natural swing to contact. If the tip and handle are out of sync at contact then balance is wrong.

    4. Test, test, test. You need to keep your total static weight to a level that you can handle, keep your total power level where it's both effective and controllable, and keep the balance right for a smooth, natural stroke. If any of that is wrong then you'll hurt yourself and/or find yourself "fighting the frame" to play effectively by breaking your swing, over-hitting, etc.

    This is why it's so important to consider frame specs when you purchase. It's much easier to add mass than to subtract mass. To subtract mass in the handle you can go with a lighter replacement grip but that's about it. For the head you can only take the extreme action of trimming the head guard to reduce mass.
     
    Last edited: Aug 15, 2014
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  8. Irvin

    Irvin G.O.A.T.

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    SW is Distance^2 times Weight. What do you think that distance is?
     
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  9. SpinToWin

    SpinToWin G.O.A.T.

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    you cannot decrease swingweight by adding weight mateā€¦ Read any research paper or swingweight explanation and you will see that.
     
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  10. PMChambers

    PMChambers Professional

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    Somewhere between the elbow and shoulder. It's a compound rotation using core, arm, elbow and wrist but the major pivot is from shoulder. I'd guess about 450mm from the butt cap for me. It's definitely not where a RCD machine has it but then a RCD machine was designed to compare racquets for matching rather than to express as a useful number to reflect actual play characteristic.
     
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  11. yangster007

    yangster007 Professional

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    You can make the racquet feel whippier and easier to get around by adding weight to the handle, but it's not possible to lower swingweight. You can only reduce the "head heavy" feel of the racquet.
     
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  12. Irvin

    Irvin G.O.A.T.

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    Swing weight is not measured by a person swinging a racket and measuring the resistance somewhere the elbow and the shoulder it is measured at a point about 4" from the butt cap. So let's look at the definition of SW from the TWU site - Reference http://twu.tennis-warehouse.com/learning_center/wtbalswt.php

    Swingweight

    Much of a tennis hit can be seen as a battle between the player and the ball to move the racquet in a circle. Swingweight is the resistance to movement in a circle. Circular motion (as in most stages of a tennis swing) occurs around a center or rotation, let's say the butt end of the handle. When you apply equal forces to the handles of two racquets with different swingweights, the racquet with the higher swingweight will accelerate less and rotate less quickly around the center of the circle. The lower swingweight racquet will accelerate more quickly. In other words, higher swingweight means less maneuverability, and lower swingweight means more.

    But the SW is not really measured from the butt cap it is measured at the pivot point about 4" up the handle. Different SW machine use different points. The closer the pivot point is to the head of the racket the lower the SW will be. The closer it is to the butt the higher the SW will be. It is like trying to pick up a 20' extension ladder. If you grab the bottom of the ladder it will be very hard to pick up but if you grab it closer to the Center of Mass (COM) it is relatively easy.

    If you want to measure the COM of a tennis racket from the Butt end (as TW mentioned above) it would be simple. Find the balance point in cm from the butt and weigh the racket is in Kg. SW = BP x BP x W. But if you want to measure the SW at a point relative to another axis point you have to put the racket in motion. The point about 4" up the handle was chosen because that's where most player index finger meets the racket. One can now measure the the time it takes to rotate the racket against a known force and determine the COM relative to the 4" point. Square of the distance the 4" point to the relative COM and you have the SW.

    Let's play with some numbers, the new RF97 weights .3572 Kg and the BP is 31.45 cm so the SW from the butt end is 353.3. When you move the pivot point up 4" the SW goes down because the relative COM moves too but not as far so the SW drops from 353 to 335.

    I have added weight to the butt end and actually seen the SW drop on a Babolat RDC. Adding weight to the butt does increase total weight but it also lowers the COM the distance to the COM has more bearing on the SW than the total weight does.
     
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  13. Irvin

    Irvin G.O.A.T.

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    Let me save one more thing. When rotating the racket at 4" above the butt end you actually have two sections of the racket you're rotating. 1 from 4" down and the other from 4" up. The lower portion will be harder to rotate because of added weight while the top end will be easier because you're moving the COM closer to the pivot. Like I said more often than not adding weight raises the SW no matter where it's added but it can lower it.
     
    Last edited: Aug 16, 2014
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  14. Attila_the_gorilla

    Attila_the_gorilla Professional

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    I doubt it. Maybe just within the accuracy range of the machine.
     
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  15. floydcouncil

    floydcouncil Semi-Pro

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    Your posts are becoming more and more like TimO's gibberish.

    Why don't you add 2kg of weight to the butt end of your racquet and see if you have decreased your SW.

    Nuff said........
     
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  16. PMChambers

    PMChambers Professional

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    I have added weight to the butt end and actually seen the SW drop on a Babolat RDC.
    I doubt it. Maybe just within the accuracy range of the machine.

    You will see it drop on a Babolat RDC machine as it uses a point 4" about the butt and mass behind the pivot will couter act / balance the system. SW has very little to do with playing mechanics, it was developed by Babolat for the sole aim of matching racquets. Unfortunately it gets used in TW as a realist expression to describe a racquet's play ability which has limited validity, though can be useful with other metrics. The concept of rotating a racquet 4" above a butt is extremely incorrect and for Babolats SW to increase it's usefulness as a measure of a racquets play it should have this pivot behind the handle. But this would result in a large machine swinging through a large arc for a purpose it was not designed for. I have not seen any manufactures use SW as metric on racquets because it's not realistic measurement of play ability.

    Swing Weight is effectively Rotational Inertia which is a double edged. The higher inertia the more stability but the more form required to change direction.

    RDC machine should only be used to match racquets, there is no other point of it. Adding mass will only every increase it's mass/weight and increase it's rotational inertia during any "noramal" shot.

    Anyway I got to go and play rather than consider mathematics, hopefully my damaged back will hold up this week. The annoyance of aging and mortality.
     
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  17. Irvin

    Irvin G.O.A.T.

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    PMChambers I would agree with that.
     
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  18. TennisCJC

    TennisCJC Legend

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    My experience is looking at the 4 basic specs which are 1. static weight, 2. balance, 3. stiffness, and 4. swing weight have enormous benefit to tennis players. I really don't care about the science but I do not if my racket is 4-6HL and has a swing weight in the 330-340 gram range, it will be a contender for me. Of course, the feel at impact, static weight and stiffness will also impact how it plays but my personal experience is swing weight tells me a huge amount about how a racket will play. I consider swing weight to be very important when selecting a racket or tuning your existing racket.

    I am sure you are correct about the science of how it is measured but as long as we measure all rackets the same, then swing weight is an excellent barometer for determining how a racket will play.
     
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  19. JackB1

    JackB1 G.O.A.T.

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    [​IMG]
     
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  20. JackB1

    JackB1 G.O.A.T.

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    This is the problem. NOBODY holds the racquet in one spot and pivots it around in a perfect circular motion. There is a lot of lifting and dropping and physically moving the racquet around in the air, in addition to pivoting it around a certain pivot point. Take 2 identical racquets. Add 10 oz. to the butt end of one of the racquets (if it were possible to do so) and you tell me it won't be harder to swing that thing around, than the stock racquet?
     
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  21. PMChambers

    PMChambers Professional

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    When comparing off the shelf racquets this technique works because racquet manufactures don't vary mass distribution a great deal, they don't excessively polarise the racquet. I think SW has some validity with stock racquet especially when read in conjunction with other specs, but, when you start adding large amounts of mass at the butt and 12 oc this technique starts to have issues, and there are a lot of pro's using very polarised racquets and even weekend warriors. It also has issues when RA differences get large, low RA will lower the effective "power" without effecting SW. Specs are useful if you have a benchmark and give an indicative idea what to expect when varying the characteristics slightly, but they're not everything. I take SW with a grain of salt as RA, string tension, string stiffness and mass distribution (IE: Graphene) have impact on play ability that the fiqure does not fully demonstrate.
     
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  22. jmnk

    jmnk Professional

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    @Irvin - honestly, why is it that every time a question of swingweight comes up you keep claiming that it is possible to lower it by adding weight in certain spot? I mean hasn't it been showed countless times that it is just physically not possible?

    Ok, I'll bite. What do you think that Distance, and for that matter the Weight, in that formula is?
     
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  23. Smasher08

    Smasher08 Hall of Fame

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    This. Irwin was clearly speaking within the context of SW measurement on a RDC machine. Weight beneath the buttcap will cause it to artificially distort the measurement. Like PMC said, the machines exist purely for racket matching.

    Imo any one measurement of a racket viewed in isolation can't give a clear picture of how a racket plays.

    In my experience, adding weight to the top of the handle and beneath the buttcap tend to have the best results.
     
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  24. Smasher08

    Smasher08 Hall of Fame

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    He's going by the measurement of a RDC machine rather than theoretical physics.

    Just find a RDC machine and do the experiments yourself! :)
     
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  25. Smasher08

    Smasher08 Hall of Fame

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    In my experience, it depends on the nature and shape of the swing you're doing.

    I find that the more HL the balance, the more maneuverable it is.
     
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  26. Smasher08

    Smasher08 Hall of Fame

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    Btw, this picture of the different types of conductor's batons illustrates some of what we're discussing, and it's the same principle with swords:

    [​IMG]

    Notice where the majority of the weight is.

    Adding weight at the top of the handle as well as beneath the buttcap makes it like the "silhouette" design, and believe me it's very maneuverable.
     
    Last edited: Aug 19, 2014
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  27. Irvin

    Irvin G.O.A.T.

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    Never, ever, not once has it ever been shown. Said but never shown. You shouldn't believe anything you hear and only half of what you see. But you can believe whatever you want.
     
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  28. floydcouncil

    floydcouncil Semi-Pro

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    You have never answered one question that I posed.

    DO YOU ACTUALLY PLAY TENNIS?
     
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  29. floydcouncil

    floydcouncil Semi-Pro

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    Looks like the shapes are more for hand comfort / preference vs. weight distribution, etc.
     
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  30. WhereIsMacMac

    WhereIsMacMac Professional

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    Adding lead tape to the strings creates a significant increase in swingweight

    Adding lead to the tennis shoes, however, will not affect the swingweight
     
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  31. Irvin

    Irvin G.O.A.T.

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    Yes I do. Thats one.
     
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  32. watungga

    watungga Semi-Pro

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    1. How do we wield?

    3. Having "you're getting a smooth, clean, natural swing to contact".. Can this be achieved thru shadowing to see if the opposite is felt?

    4. "keep the balance right for a smooth, natural stroke" How do we notice the opposite of balance?
     
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  33. jmnk

    jmnk Professional

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    this is like saying that it has never been shown that probability of a given event is never less than 0. By the very fact how probability is defined it cannot be less than 0 - but I'm not sure how one would 'show' it.

    Same with swingweight. By the very fact how swingweight is defined it is not possible to add a mass to an object and lower object's swingweight. If you understood what swingweight definition means it would be clear to you.
     
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  34. jmnk

    jmnk Professional

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    would you care to answer? And where did you get this formula from anyway?
     
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  35. watungga

    watungga Semi-Pro

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    Swingweight is centrifugal or centripetal relative to the pivot point.

    Pivot point, in this case, is dynamic and is dependent on the hitters preferences.
     
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  36. Irvin

    Irvin G.O.A.T.

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    The Physics and Technology if Tennis written by Howard Brody, Rod Cross, and Crawford Lindsey. Chapter 3 - Weight, Balance, and Swing Weight written by Crawford Lindsey and Howard Brody. Page 30

    If you don't have a copy it basically says that SW = mass x distance x distance in bold print. And that distance is from the point of rotation or the pivot point. The units of SW which are often left out are kilograms and centimeters. It also goes on to say, "...consider the racket as an accumulation of small bits of mass. Each small bit of mass has a swingweight of mdd, the sum of all these swingweights is the total swingweight of the racket."

    Now we all know we can't break down every small bit of mass so we have to measure swingweight by some other means. One of those pieces of apparatus that measures SW is the Babolat RDC. I'm not sure how accurate the RDCs are but it is pretty well considered the standard in Tennis SW. What I'm saying is I have added weight to the butt end of a racket and seen the SW drop. What you're saying is that I'm lying. Like I said before believe whatever you want to believe.
     
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  37. JackB1

    JackB1 G.O.A.T.

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    Irvin...you are stuck on a formula and not looking at real world physics. Even though the pivot point where swingweight is measured may be a few inches from the end of the handle, any weight you add to the very end of the handle will make the racquet heavier to move around and through the air. Just try it yourself. Tape something small and heavy to the very butt end of any racquet and swing it around and see if it feels heavier than before you added anything.
     
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  38. Irvin

    Irvin G.O.A.T.

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    JackB1 I know that, jmnk knows that, you know that, Crawford and Brody know that. But the question is does an RDC machine? Let's look at how a physical pendulum works (this is how the TW calculator works.) A racket is rotated from a pivot point and timed to see the timing of a period. The farther the COM is from the pivot point the longer the period. The closer the COM is to the pivot point the shorter the period. Adding weight on bottom of the pendulum will lengthen the period whether the head or the handle is down does not matter. Adding weight on the top will make the period faster. Where ever you add the weight moves the COM for the Physical pendulum. So this begs the question: Is it possibly to add weight to a racket and lower that SW and if so where is that point. I'm saying yes (sometimes) and that point is the butt end of the racket.

    Adding weight on the butt can counterbalance the COM relative to the pivot point and distort your SW readings. I guess if you really want to be accurate your should cut off the bottom 4" of the racket and find the COM of each section individually, determine the SW of each section and add them together. But that would be impractical.

    I think a better way is to square the balance point (cm) and multiply time Weight in Kg (grams/1000.) Of course that's not accurate either is it? But it's a lot easier that finding and matching SWs. I also think the SWs would be very close between rackets matched that way or at least enough so the average player can't tell the difference.
     
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  39. jmnk

    jmnk Professional

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    I do have that book. And what the book says is correct. But it is NOT what your formula stated. In your post you have stated that

    SW is Distance^2 times Weight.

    as you can see, there's no 'weight' in SW formula. there's only mass. You probably think it does not matter. But it does matter, and it is there point of the argument. If you take an object to space where there's no gravity, its SW is going to be exactly the same as it is on earth, because the mass does not change. But it would not be true if SW depended on the weight, would it?that 'counterbalancing' as you call it would not be helping you at all in space, it would only make the racket MORE resistant to change in motion.


    great. and that distance is from the point of rotation to what? i help you - to the point-mass you are trying to determine the SW of. That formula is --only-- applicable if you are dealing with point-mass. Anything else, be it a racket, a random rod, any non-uniform object - you can't really use it because it is not a point mass.

    exactly true. the total SW of an object is the sum of all those little swingweights calculated for every tiny bits of mass that could be considered point-mass. read that again - it is a SUM.
    So now you take a racket. You measure the SW, or know what it is.. Let's say it is Racket_SW_X. Now you add mass Y anywhere on the racket, in your case at the handle. Since now the object is a combination of a racket and additional mass, its SW is a SUM of original racket SW --plus-- the SW of that mass you have just added. Since you can't add mass that is less than zero (meaning Y>0) than the SW of that new object is Racket_SW_X + mass_SW_Y. And that is guaranteed to be greater than Racket_SW_X (ok, to be exact, if you add that mass Y at the pivot point than that resulting SW will be the same as the original one, but never less)
    [/QUOTE]

    how you measure the SW, whether it is via pendulum method, or on RDC machine, does not change what I've explained above. If your measuring method results in SW being less after the mass is added than you have three possibilities:
    • the change is so small it is within standard error of the method. You just need to perform sufficiently enough tries to come up with the average.
    • operator error. Enough said.
    • the method does not measure Swingweight, but some other characteristics of the object. in that case you may want to write babolat and ask them what that RDC machine actually measures.

    I'm not suggesting you are lying. but i'm convinced you do not quite understand what SW means, and possibly make some measuring errors, and as a result you are trying to somehow explain the impossible.

    or are you flatly suggesting that Babolat employs not a single person that is familiar with what a Swingweight is, and they designed RDC machine the wrong way?

    no idea what you are saying here. No idea what a value resulting from "to square the balance point (cm) and multiply time Weight in Kg (grams/1000.)" would mean for an arbitrary non-uniform object. It would definitely not be a Swingweight.
     
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  40. Irvin

    Irvin G.O.A.T.

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    In physics, mass is a property of a physical body which determines the body's resistance to being accelerated by a force and the strength of its mutual gravitational attraction with other bodies. The SI unit of mass is the kilogram (kg.)

    Maybe you should take an RDC to the moon and see what happens.
     
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  41. Irvin

    Irvin G.O.A.T.

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    No that's impossible unless you chop the racket into all those itty bitty pieces.
     
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  42. Irvin

    Irvin G.O.A.T.

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    Well I agree now but unless you figure out all those itty bitty pieces you can find the SUM
     
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  43. Irvin

    Irvin G.O.A.T.

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    Simply put match the weight and balance.
     
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  44. JackB1

    JackB1 G.O.A.T.

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    Whether or not the RDC machine "knows it" is irrelevant to how humans sinwg a tennis racquet. It's a fun thing to mention, but its not worth threads and thread of arguing over.
     
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  45. Irvin

    Irvin G.O.A.T.

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    Just like jmnk says the SW of a racket is the sum of all the swingweights
    but the RDC does not have a little man with a calculator summing up all those swingweights. The RDC uses the COM of the complete racket relative to the pivot point to determine the distance from the pivot to the COM and the mass of the racket. That center of mass changes when you add mass anywhere on the racket but at the pivot point. If the COM moves toward the handle the SW MAY go down, if the COM does not move or goes away from the handle when mass is added the SW will go up.
     
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  46. Irvin

    Irvin G.O.A.T.

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    Let me try to explain this a different way. If I add a small amount of mass, say .001 Kg (1 gram) it may not be enough to round the mass of the racket up but it could change the COM enough so that it is rounded down. If this happens the SW could go down. But all I hear is that it is impossible and it didn't happen.
     
    #46
  47. jmnk

    jmnk Professional

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    really?? Could you kindly point out at what moment during measuring the SW on RDC machine you are required to enter the COM of the measured racket?
    Or are you suggesting that the RDC machine somehow knows it on its own? If so - how does it know it?

    or perhaps, just maybe, RDC machine does not need to know COM to measure the swingweight? hmm, what an idea.

    Listen, I respect your tips on stringing and such, but you are just not correct on this SW topic....
     
    #47
  48. Irvin

    Irvin G.O.A.T.

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    When using an RDC you are not required to enter anything you mount the frame, select the SW function, and push the frame to the far left, let go, and read SW.
     
    #48
  49. Power Player

    Power Player G.O.A.T.

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    Irvin is correct, I saw it today.

    Put a stick with stock grip on the Babolat RDC and it measured 302 SW.

    Put a lighter babo skin feel on it and the SW went up to 304. I believe the balance shifted a little more towards the head.
     
    #49
  50. jmnk

    jmnk Professional

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    of course you don't need to enter anything. But it was you who stated

    well, if RDC uses the COM of the racket, as you are implying, than you either have to enter it, or the machine figures it out on its own. You agree that you do not need to enter it. So you must be saying that the machine somehow figures it out. Great.

    Tell me than, why, if you want to find out the COM of the racket (i.e. the balance), you MUST do it by hand by placing the racket on the balance beam and reading from the scale?? Wouldn't it be simpler and cooler if the machine told you what the COM is when you do the swingweight measurement??

    I tell you why - because the machine DOES NOT know on its own what the COM is. It DOES NOT know what the distance from COM to the pivot point is. And it DOES NOT use this non-existing knowledge to measure the swingweight. You may want to re-read the manual and/or consult with Babolat if you think otherwise.
     
    #50

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