Optimum Racquet Balance for Performance II - MgR/I Data for ATP Pros

Discussion in 'Racquets' started by travlerajm, Jul 5, 2011.

  1. travlerajm

    travlerajm Hall of Fame

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    Look, buddy.
    I have a degree from Stanford in Biomechanical Engineering.
    I have a PhD in Chemical Engineering from the largest research university in the world.
    The reason I'm in Vienna this weekend is to receive the highest international award in applied science innovation in my field.
    I've read every tennis-related article by Lindsey, Brody, Cross, Haake, and Goodwill, and I have respect for their work.
    And I've spent enough years of careful experimentation with racquet customization that I am quite certain I know more about how lead tape affects racquet than any of them. The reason I continue to discuss the MgR/I concept is because it works, and because it's an essential tool for anyone interested in optimizing the performance of a tennis racquet. I'm in the process of preparing a comprehensive book on racquet customization in my spare time, which will more formally present the concept, along with other key concepts. I plan to use Lindsey as editor. Until I see something more useful than venom from your posts, I don't have any intention of consulting your help.
     
    Last edited: Sep 8, 2012
  2. Power Player

    Power Player G.O.A.T.

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    Stoneage i have to say your app is so great that it automatically lends you a ton of credence on this board. I would not worry about it as many of us question a lot of the ideas presented in this thread and what you are saying is legtitimate to me.
     
  3. Mig1NC

    Mig1NC Professional

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    I have a bachelors degree in Computer Information Systems... Which means I have no idea what half this means...

    But I will say that regardless of the scientific validity of the formula, it does work for me. I have found when I tune my racquets using this formula (and then fine tune) they just feel right. It just clicks.
     
  4. jmnk

    jmnk Professional

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    two questions:
    1. Have you done any 'blind test' to verify that 'it just clicks'?
    2. If you need to 'fine tune' some more - does it mean you end up with MgR/I --not-- being equal to 21.0? if so, doesn't that mean that 21.0 is not any magic number? It's like saying that the 'best' weight for a tennis racket is 290 grams - but you have to fine tune it to suit you. For a player A he will fine tune it to 310gr. Other will tune it to 280 gr. the rackets will feel great for a respective player. Does that mean that the 'best' weight is 290 gr, or not?

    Look, if it makes you play better with believing that your racket should be at MgR/I=21.0 than by all means use it. I believe I play better in blue shorts and black wristbands. But let's not claim there's some scientific proof or evidence that racket with MgR/I = 21.0 is 'the optimal one'. No one showed that, including travlerajm.
     
  5. Ramon

    Ramon Hall of Fame

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    You got that right! I have Sten's apps on my iPhone. They work great and he constantly keeps them updated.

    RacquetTune and SwingTool are the best apps of their kind for tennis players. If you customize your racquets or really want to know how much tension your strings are losing, you need to get these apps!
     
  6. Circa 1762

    Circa 1762 New User

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    I think you're misconstruing travlerajm's argument. Each person, the theory goes, has an ideal MgR/I, but this ideal MgR/I depends on things like arm length. Therefore, each person's ideal MgR/I is going to be slightly different. Travlerajm has looked at the specs of pro's rackets, and based on the assumption (I think) that pros are likely to have MgR/I's close to their ideal, found that the pros cluster around an MgR/I of 21.0 (although again, there are variations due to things like height). As a result, he's suggesting (travlerajm, correct me if I'm wrong) that you might want to start with your search for your ideal MgR/I around 21.0. He is not saying that your ideal will necessarily be 21.0.

    Based on a series of blind tests - for example, setting up two rackets with the same weight and swingweight but different balance, leading to different MgR/I's - I've concluded that my ideal MgR/I is around 21.2. I'm shorter than the average pro (5'8"), so this isn't too surprising. And these were blind tests with the exact same racket model and on the same day, so I'm pretty sure the differences I felt were real. So basically, don't just set your racket up to MgR/I = 21.0 and call it a day. If you have two rackets, set one to 21.0 and one to 21.1, and see which you like better (you should feel a difference). Say you like the 21.1 racket better. Next, leave that one the same, but set the other one up to MgR/I = 21.2. If you still like the 21.1 racket, you can be pretty sure your ideal is around 21.1, and almost positive it's between 21.0 and 21.2. You can continue to do blind testing like this until you zero in on your ideal.
     
  7. travlerajm

    travlerajm Hall of Fame

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    Nicely summarized! This post might also be useful:
    http://tt.tennis-warehouse.com/showpost.php?p=5859118&postcount=17
     
  8. stoneage

    stoneage Rookie

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    Let me begin by saying that I am not out to spread venom and I apologize if you get that impression. As I already said I have been intrigued with the concept and I have spent many hours trying to find out what it really means, and got a little annoyed of the lack of solid information. I must admit I am a little surprised by your reply, with a background like that you should be able to give better answers to the questions asked by me and others.

    You (and others) are often referring to the fact that the concept works in practice and as I have said I have never doubted that. With all your additional requirements you end up with a fairly heavy, head light racquet with rather high swingweight. Not a radical concept for stable play, and it is not surprising that people like. No problems there.

    But beyond that you are claiming that the formula is describing a lot of things in a tennis swing. You didn't have to do that to make your tuning specs creditable, it would have been enough to refer to experience and your collected data. But you are making those claims and then it is your call to give evidence that they are true. You have not given one single shred of evidence. You say that you could feel how MgR/I works. Feelings are fine and probably more important than physics for a good tennis game. But physics isn't based on feelings, so if you present something as a physical fact it must be based on math and/or solid measurements. You have given neither.

    Lets just pick one example (of many): "The point is that tuning the racquet's natural swing frequency to match the natural swing frequency of the arm will significantly improve control by ensuring that your racquetface naturally stays perpendicular to your target as it passes through the hitting zone". This is a very specific claim of the natural swing frequency of the racquet, i.e. MgR/I, being connected to the swing frequency of the arm (whatever that is). This problem is possible to analyze and a proof could be given that is more than just words. If you can't do that don't make the statement. I might sound negative when I express my doubts, but if you had described how you reached that conclusion I or someone else might have been able to give more constructive critique, or just applauded your result.

    Maybe you are saving it for your book, then I will read it with great interest (honestly).
     
    Last edited: Sep 8, 2012
  9. stoneage

    stoneage Rookie

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    Guys, thanks for the positive feedback.

    And I probably shouldn't have gotten into this discussion, it won't lead to anything :)
     
  10. Mig1NC

    Mig1NC Professional

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    Stone, make your apps for Windows Phone so I can try them out :)
     
  11. jmnk

    jmnk Professional

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    That's nicely stated. Note however that this is no different than saying that each person has ideal mass of the racket, balance and swingweight - which very well may be true. In fact, as stoneage pointed out, combining those three values in some sort of equation (like MgR/I) and implying that that particular equation should result in some sort of particular number (or range) for the racket to be perfect is counterproductive. This is because even though one may have a particular optimal racket, balance, and swingweight (as in one optimal value for each) you lose that fact when you multiply the values. Please read this post by stoneage http://tt.tennis-warehouse.com/showthread.php?t=352140 when he nicely explains (with numbers, not feelings) that there are (quoting) "infinite number of very varying solutions making it impossible to use [MgR/I) as a design criterion". There was also a post somewhere that noted that $15 Walmart racket has MgR/I~21.0 while Head Prestige, widely regarded as one of the best rackets ever, was nowhere close to that value.
    But again, you can read into it whatever you believe.
     
  12. Bartelby

    Bartelby G.O.A.T.

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    So it will already work for the new edition of ios or will it need an upgrade?



     
  13. kaiser

    kaiser Semi-Pro

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    Hear, hear!
     
  14. stoneage

    stoneage Rookie

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    I don't want hijack this thread so if you have more question regarding racquetTune please mail me privately.

    You mean iOS 6? Since it isn't out yet I don't know :)
    However, I don't think it will be a problem from what I have seen in the beta-version.
    But I will check as soon as it is launched and do updates quickly if needed.

    I have started a cooperation with a partner concerning Android. We are starting with another app (sprintTimer), but hopefully there will be a racquetTune for Android eventually.
    Windows Phone, however, is not on the horizon I am sorry to say.
     
  15. floydcouncil

    floydcouncil Semi-Pro

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    GIVE THIS MAN A COOKIE!!!!!!
     
  16. TaihtDuhShaat

    TaihtDuhShaat Semi-Pro

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    I have extensively tested Travlerajm's MgR/I formula on mine and others' racquets over the last 1 1/2 years, and have proven it's truth many times over.

    I'm sure MgR/I could be modeled in a lab using a pendulum of known mass with a freely rotating joint attached to a tennis racquet with a MgR/I matched to the pendulum, and measuring the acceleration over many points of the racquet tip to the acceleration of the freely rotating joint of the pendulum over 1 period.

    The formula's worth can even be proven visually. Maybe I'll try to post a video, but if I compare a perfectly tuned racquet to one that has a MgR/I that is too low or 'slow' and 'shadow' swing my forehand very slowly from backswing to follow through with a loose wrist, the racquet head with the 'slow' frequency will lag behind my hand after the backswing and through the contact zone. The tuned one will stay in the same plane with my loose wrist joint all the way through. This works as well using a continental volley grip and tracing a 'U' in front of your body. The tuned one's stringbed will stay in a constant angle to the wrist while the 'slow' one will fall behind the hand while tracing down the 'U' on both sides. The same can be applied for the 2HBH once well tuned, and even the beginning of the serve motion.

    IMO, naysayers can prove it to themselves with enough dedication (since there is a learning curve). It took me a few months of testing at a wall and shadow swinging slowly in front of a mirror to even know what to feel for by following the procedure Travlerajm linked to above.

    My ideal happens to be close to 21 for my semi-western FH (20.93 if I use a western FH) and around 22.5 for my 2HBH. I am 5'9" with average length arms. These values are tuned for me using any weight of racquet, as long as the balance and SW are changed to meet these values. I just also happen to prefer the effortless power, stability, spin, shot directionality regardless of incoming angle/pace/spin, and repeatability of shot that the high SW gives me. Because of this, I must then also use a high weight racquet with HL balance meeting the MgR/I requirements if I want my racquet head to be synched with my wrist. To use a frame with a SW in the 365 range really just means that 30 or so grams must be added to the top of the handle (of a prostock or light starting frame) if I want my frame to swing synched with my wrist, and this ends up making the SW much easier to wield. Thus, there really are no tradeoffs for me by using a frame like this. What I have learned has just corroborated and given further credence to Travlerajm's discoveries.
     
    Last edited: Sep 10, 2012
  17. Power Player

    Power Player G.O.A.T.

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    ^^^

    I hope you know that sounds insane.lol.

    If my racquet was not "tuned", I would be too early or late on my shots. And yes, I experiment with lead when I buy sticks.
     
  18. ART ART

    ART ART Semi-Pro

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    @travlerajm:

    check this post with Novak racket specs:
    http://tt.tennis-warehouse.com/showthread.php?t=441393

    Specs strung+overgrip+dampener, are:
    Mass: 360gr
    Balance: 33cm
    SW:371

    So the MgR/I = 20,35 and MR^2= 392

    Far away from the ideal MgR/I = 21,0 and MR^2= 385

    Any comments about it ?
     
  19. travlerajm

    travlerajm Hall of Fame

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    Remember, the 21.0 number is not the ideal for every player. It is a good starting point for most players when tuning; but many factors, such as arm length, grip type, whether you use an overgrip, and wrist band use can shift the optimum for the particular player.

    The longer the arms, the slower the naturally swing speed of the arm, and the lower the optimum MgR/I value. Shifting the grip more toward western also shifts the optimum MgR/I lower. And a wrist band adds several ounces of weight to the arm pendulum, slowing down the hand through the downward gravity-powered first portion of the forward swing and thus shifting the optimum MgR/I lower. Using an overgrip also shifts MgR/I optimum slightly lower by shifting the grip position almost a millimeter up the handle.

    Given Djokovic's slightly taller than average height, longer than average limbs for his height, nearly western grip, and large wrist band, his MgR/I value is right where I would expect it to be.
     
    Last edited: Oct 5, 2012
  20. kaiser

    kaiser Semi-Pro

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    So what about big vs small hands, wide vs narrow wrists? Aren't your theory and equations suggesting far more accuracy and preditive power than they really have?
     
  21. travlerajm

    travlerajm Hall of Fame

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    I have no basis to compare hand size for the players, so I can't comment on that. But experimenting by adding mass to my wrist is something I have tested carefully.

    Anyway, the point of the MgR/I formula is not predictive power for other players. Rather, the point is that awareness of the MgR/I value allows you to predict how adjustments to your racquet mass distribution will affect the timing of your swing, and that this formula is an effective tool for tuning your racquet to optimize your performance.

    Also, once you find your personal optimum MgR/I value, you can use it to predict what specs will work for you when you go up or down in swingweight. In other words, it allows you to decouple swing dynamics from impact dynamics when you experiment with different weight distributions.
     
    Last edited: Oct 5, 2012
  22. kaiser

    kaiser Semi-Pro

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    So you are saying that because of the many possible differences in body proportions between different players, the optimal configuration of a racket can vary considerably? That would make sense to me.

    This leaves one crucial component in your theory I never understood. In your formula there is only one acceleration term, g, which in your posts you have related to a high take-back. Does this mean that the primary force acting on the racket in your model is gravity? In other words, that in your model the tennis stroke is treated as a dual pendulum consisting of racket and arm swung through an arc from the highest takeback position by the force of gravity alone?

    Does your model account for the acceleration of the racket and arm due to the hip and shoulder turn? Why is there no term in your formula which expresses this acceleration?
     
  23. ART ART

    ART ART Semi-Pro

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    @travlerajm:

    and the MR^2= 392 ? it's far from 385

    Maybe we need real specs like those from Novak and Almagro, in order to conclude something, but all in all it's allways a personal preference for each player, not some right or wrong numbers...

    But, I apreciate a lot your efforts and theory, and there's allways some fire on it...

    Cheers
     
  24. floydcouncil

    floydcouncil Semi-Pro

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    We can ALL conclude that the point is MOOT.
     
  25. travlerajm

    travlerajm Hall of Fame

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    When I first started trying to relate a tennis swing to physical parameters, I made some of the same misassumptions that most people make. I wrongly assumed that the swingweight is what determines how much effort goes into getting the racquet to "come around."

    I eventually found that a much more accurate way to model a swing is to divide it into two distinct parts. The first part is the mostly gravity-powered part of the swing where the racquet goes from the top of the backswing to the bottom of the swing. The second part is the portion of the swing where the player adds force behind the racquet handle to accelerate the racquet forward and upward against gravity and through the hitting zone.

    During the first part of the swing, the face of a the racquet naturally rotates toward the ball. If the racquet has a "tuned" MgR/I value, then no added torque from the wrist muscles is needed to ensure that the racquet is facing the target at the end of the this part of the swing. Since gravity is providing nearly all of the acceleration, the final angle of the racquetface at the end of this gravity-powered first portion of the swing is nearly entirely determined by the MgR/I value (assuming a relaxed wrist is used).

    I believe that our brains sense the bottom of the swing as the cue to "switch on" the applied force that starts the acceleration through the hitting zone. However, without a tuned MgR/I value, you cannot use a relaxed wrist, and your arm will tend to wear out over the course of a match from exerting the wrist muscles on every shot.

    Once the second part of the swing begins, most of the acceleration is applied by the player. As long as the racquet starts the hitting zone with the right racquetface angle, the player can easily vary the applied force to achieve different results on the ball. But if MgR/I is not tuned, then the second part of the swing will begin with the racquetface not quite at the right orientation, leading other adjustment forces from the wrist to be needed during the second part of the swing as well.
     
  26. kaiser

    kaiser Semi-Pro

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    So the MgR/I theory only applies during the backswing phase while the racket drops from high to low. Can you illustrate graphically what you mean when you say "the final angle of the racquetface at the end of this gravity-powered first portion of the swing is nearly entirely determined by the MgR/I value" and "if MgR/I is not tuned, then the second part of the swing will begin with the racquetface not quite at the right orientation"? How does the racket face orientation change during this phase?

    I always understood that you were referring to the racketface orientation at the end of the stroke when it strikes the ball. As I understand it (see for a more authoritative description this article by Rod Cross: http://www.racquetsportsindustry.com/articles/2006/04/racquet_handle_weighting_and_m.html), the orientation of the racket face prior to impact changes as follows: During the second phase of the swing, as you defined it, the racketface first lags behind the wrist as the arm moves forward through the force applied by the player. Then, as the arm slows down at the end of the stroke, the racketface quickly catches up and accelerates forward through an arc around the wrist (dual pendulum), ideally striking the ball at the exact moment when the racketface is perpendicular to the intended hitting direction. Hence, slight variations in the timing of these processes during the second phase of the stroke will lead spraying of the ball from left to right. That's why I always thought you were referring to this second phase of the stroke when you were discussing MgI/R.

    How does the timing of the first, backswing phase of the stroke affect the orientation of the racket face at impact? And doesn't the timing of the second, player-powered, phase of the stroke have a much more direct effect on the orientation of the racketface at impact and hence the accuracy of the shot?
     
  27. jstout

    jstout New User

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    A different way to look at the MgR/I is by a pendulum period.

    M = kg, g = cm/s^2, R = cm, I = kg*cm^2
    MgR/I is (kg * cm/s^2 * cm) / kg*cm^2 = 1/s^2 so Period = 2 * PI * SQRT(I/MgR) which will be in seconds

    Travlerajm's optimal 21.0 is ~1.371s and Djokovic's 20.237 is ~1.397s. The difference between values are generally in hundredths of a second. I've tried to collect as many measured pro racquet specs as possible and the range tends to be 19-22 (1.44s-1.34s) with the average being 20.5 (1.38s)

    MR^2 is a byproduct and ranges can be very extreme: 315-450 with the average being 374. Djokovic's 392 is actually close to 385 and not far away in that regard.

    I've used travlerajm's equations myself and in my opinion adjusting Swingweight, Effective Mass, and MgR/I is a good way to tweak a racquet to what feels best to you.
     
  28. travlerajm

    travlerajm Hall of Fame

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    I think Cross's statement is interesting:
    "Having extra weight in the handle therefore allows a top player to control what he is doing. It slows down the forward motion of the handle and the backward motion of the head just enough so that he can swing the head around with a reasonable effort rather than an excessive amount of wrist torque."
    The extra weight in the handle that Cross refers to (that permits swinging without wrist exertion) is the weight required to bring MgR/I up to a player's personal optimum value (most lightweight stock racquets lack enough handle mass for MgR/I to be optimized).

    However, according to Cross's explanation, adding weight to the butt of the racquet would accomplish the task. But according to my findings, that is not true. The handle weighting must be higher in the handle to have the desired effect (i.e., increasing MgR/I). Thus Cross's explanation can be easily disproved (with a simple on-court experiment).
     
    Last edited: Oct 5, 2012
  29. travlerajm

    travlerajm Hall of Fame

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    ART ART,
    As jstout pointed out, 392 is very close the the statistical apparent optimum. Also, notice that the sample size is lower at the high end of the player list than at the low end. And you may have noticed that my racquets are at 390, which I find to work best for me after years of experimentation.
     
  30. corners

    corners Legend

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    I've also found it useful, and matching MgR/I of two sticks with quite different swingweight and static weight seems to give the same "swing feel" to both sticks, even though they are both very different from the conventional racquet-tech point of view.
     
  31. kaiser

    kaiser Semi-Pro

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    Thus? You just stated that MgI/R is only valid for the first, backswing phase of the tennis stroke (the drop from high to low driven by gravity). Cross is talking about the second phase of the stroke, so how can your MgI/R theory disprove that?
     
  32. travlerajm

    travlerajm Hall of Fame

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    The first phase of the stroke is the important part for control, because it determines the racquetface angle and the racquetface angular velocity at the start of the hitting zone. Thus what happens in the first part of the stroke determines the forces that the player needs to apply in the second part of the stroke.

    My point is that:
    A) Cross has made the same observation that I have -- that adding the right amount of mass to the handle can improve control by allowing the player to relax the wrist through the hitting zone.
    B) Cross explains the phenomenon with his force balance model, while I explain it with the MgR/I pendulum model.
    C) It is easy to determine which model is more correct, because the models predict two completely different results:

    Both models predict that adding mass to the top of the handle can enable a relaxed wrist through the hitting zone. But Cross's model predicts that adding mass to the butt of the racquet will work even more efficiently than adding to the top of the handle, while the MgR/I pendulum model predicts that adding mass to the butt of the racquet will have almost negligible effect (for a forehand).

    Thus all you need to do to prove which model holds up (and which model fails) is do an experiment adding mass to different parts of the handle and then attempt to hit a moving ball toward a target with a relaxed wrist, see how targeting accuracy is affected, and find the amount of mass needed to maximize control. I have done this experiment hundreds of times. In fact, I do it every time I set up a new racquet or change my setup to ensure that my balance is optimized.
     
    Last edited: Oct 7, 2012
  33. kaiser

    kaiser Semi-Pro

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    Now this is not clear to me at all, and in my understanding Cross is implying exactly the opposite. Do you have any objective proof for this statement (i.e. beyond your own subjective experience)? Or at least can you illustrate it with a diagram, figure, or something?
     
  34. Readers

    Readers Semi-Pro

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    How do you calculate I?
     
  35. Readers

    Readers Semi-Pro

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    Should I just use this? The poster doesn't sound too confident.
     
  36. JohnB

    JohnB Rookie

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    That's the one.
     
  37. newyorkstadium

    newyorkstadium Semi-Pro

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  38. Readers

    Readers Semi-Pro

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    Thanks, seems that one is correct.

    Seems both of my heavily customized gold 99 and stock Blue 99 falls into the ideal range already. Maybe it's a sign that I need to stop change/tweaking and work more on techs.

    Still I need a higher SW on the blue. (I am not even going to consider the "ideal" SW in this thread, no way I can swing it).
     
    Last edited: Oct 14, 2012
  39. mgaia57

    mgaia57 New User

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    @travlerajm
    Hey men, intresting thread here. I was thinking about adding weight in my raquet and didn't know where to start and this pretty much put some light into the subject for me
    If it is asking too much, could please make the math for me on my raquet and height? I use the new Head Prestige Pro and I am 177 cm high. Don't know if this is useful but I use Babolat RPM Blast 16 @ 52.5
    Thanks!
     
  40. LeeD

    LeeD Bionic Poster

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    Balance.
    Sword fighting and tennis racket swinging are similar any many respects.
    Several basic strokes, several less used alternative strokes, and as many reposts and replies....
    What is the ideal balance for a sword, or a sabre, epee', foil?
    There is none! It's based on strength of handle to hilt to blade, since most cutting weapons are made of solid steel of some kind. Balance is determined by usage. It's abliity to not break, strike hard, defend against hard strikes.
    But tennis rackets are made of composites, and as such, can have enough strength to make balance a completely different factor. Tennis racket balance is solely to aid the player, not for fear of breakage.
    Nobody knows what balance is ideal for the PLAYER. Baseball bats are head heavy, hockey sticks slightly head heavy, golf clubs definetely head heavy, while tennis rackets are mostly head light in heavy weight rackets, and head heavy in lightweight rackets.
    Maybe SW has everything to do with it, or at least more to do with it.
     
  41. newyorkstadium

    newyorkstadium Semi-Pro

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    Jan 12, 2012
    Messages:
    585
    Travlerajm, I am 6 ft 4 with an eastern forehand. I have a racket with a 4 5/8 grip (natural size) and one with 4 3/8. What is my mgr/i for these rackets?

    What would it be if I changed to a semi-western grip? What would it be for a two-handed backhand?

    Many thanks
     
  42. Alain

    Alain New User

    Joined:
    Feb 4, 2010
    Messages:
    31
    HI,
    I have 5 Volkl PB10 mid . My prefer MGR/I° is 20,90 and the best swingweight with this racquet seems to be for me 325: better manoeuvrability with lesser weight possible .
    Two of them SW are 331 with higher balance (+0.2) and weight( +2g) than the others and MGR/I° is 20,70 .
    I used paper glass to sand the bumper ( from 3 to 9 o'clock) and decrease it easily 2g .
    Now the result is the same for the 5 racquets: 339g strung , Balance 31,7 , swingweight 325 .

    Sanding the bumper, MGR/I° has increased from 20,70 to 20,82 .
    Now just adding 5 g surgrip, the MGR/I° is 20,90, SW 325, 344g, Bal 31,4.

    Question: is it acceptable to increase MGR/I° sanding the bumper ( 2 g is very easy) when you accept or need to decrease mass, balance, and SW or do you always prefer to increase weight at 7" to increase MGR/I° ?
    Or are you always wrong sanding the bumper (increase flutter at the top of the racquet ?) .
    Because for some racquets ( Becker London for example), if you don't sand the bumper you need to add a very high mass at 7" to increase MGR/I° to 21 ( 15 to 20g) .
    For a Babolat APD you will probably need 20g at 7" to obtain MGR/I° 20,90 .
    For a Volkl PB 10: 8 g at 7" and a 5g surgrip will increase the weight at
    356g and MGR/I° 20,90 .If you decrease the bumper for 2,5g you will obtain the same MGR/I° with only 345,5g which is more acceptable.

    Thank you

    Alain
     
  43. travlerajm

    travlerajm Hall of Fame

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    Alain,
    If you prefer a lighter racquet, there is nothing inherently wrong with shaving mass off the bumper to reach your optimum MgR/I value.

    I personally prefer the extra stability of a higher swingweight, but others may value maneuverability more than I do.
     
  44. travlerajm

    travlerajm Hall of Fame

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    You will need to experiment for yourself to determine your optimum MgR/I value for each type of forehand. I refer again to this post for assistance with the tuning process:
    http://tt.tennis-warehouse.com/showpost.php?p=5859118&postcount=17
     
  45. swfh

    swfh Rookie

    Joined:
    Aug 8, 2011
    Messages:
    340
    Currently have a mgr/I value of 21.26. How can I get it down to 21?
    Current setup
    Dunlop 4d 300 tour
    360 g
    32.9 cm balance
    345 swingweight

    Thanks.
     
  46. travlerajm

    travlerajm Hall of Fame

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    Assuming your SW has been measured accurately, try adding 5g at 12 o'clock.
     
  47. swfh

    swfh Rookie

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    Aug 8, 2011
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    Any way I could do it by getting more head light?
     
  48. travlerajm

    travlerajm Hall of Fame

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    Sure. After you add the 5g to the tip, then add more mass than that to the butt.
     
  49. swfh

    swfh Rookie

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    Aug 8, 2011
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    340
    Thanks a bunch. Will test it out and see how it goes.
     
  50. ART ART

    ART ART Semi-Pro

    Joined:
    Apr 20, 2004
    Messages:
    644
    Giving a few more points to travlerajm, I have made a few more new tweaks in my racket, specs:
    Mass: 354grams
    Balance: 32,2cm
    SW:338
    MgR/I: 21,06

    It works very very good, very good timing on both wings(one hbh), with very good control/power/spin.

    Once again it seems that MgR/I works well, but with static weight beeing above 345~350grams, to have good stability/power/spin, without having a huge swingweight to deal with.

    Again, thank's for sharing it travlerajm.
     

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