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

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

  1. JohnB

    JohnB Rookie

    Joined:
    Jun 16, 2012
    Messages:
    197
    I made a mistake about the mass of the arm. Travlerajm, as you mentioned, was talking about the forward part of the stroke where the weight of the arm would be of influence.

    Since airpressure and temperature are not covered in the formula, I am pretty sure it not relevant for the formula. In reality in might be of a very, very small influence. Because the rackettip has a longer way to travel from top to bottom than the arm, the speed of the rackettip will be higher if it is in tune with your arm, therefore the rackettip will be more influenced by airresistance than the arm. But, I think that because of the relative low speed of the arm and rackettip at the high to low part of the stroke, the influence would be small. In the part of the forward segment of the forehand, the rackettipspeed will much higher. So airresistance will play a greater part.

    You are supposed to let the racket drop by gravity at the beginning of the forehand, so the lenght of the arm is important and not how strong or how fast you can swing.

    This is my personal experience. With thinner grips I am more able to play wristy shots and those stretchshots you mentioned. I think with thinner grips, if you play not on your optimum value, you can "correct" the swingpath easier than if you play with a thicker grip.

    I don't know about the wristband location. Maybe a simple way to test is: take a racket close to optimum Mgr/I and put a watch or something on your wrist and play. Then move that watch to your upperarm and play and check if the timing/direction of your forehands differ. My guess is that the higher up the arm, the higher the optimum value.

    By the way, the Mgr/I concept is only a part of tuning a racket. What really helped me was a thread by Stoneage (Combining weight, balance and swingweight)
     
    Last edited: Dec 23, 2012
  2. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Stoneage mentioned air pressure and temperature in his critique of mgr/i. Just found out stoneage was being sarcastic about this. Never mind.
     
    Last edited: Jan 30, 2013
  3. cmendez79

    cmendez79 Semi-Pro

    Joined:
    Nov 5, 2009
    Messages:
    435
    Do you have the link to stoneage thread?
     
  4. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    never mind
     
    Last edited: Jan 30, 2013
  5. JohnB

    JohnB Rookie

    Joined:
    Jun 16, 2012
    Messages:
    197
    Mgr/I is indeed very personal. I've heard some success stories where people played with different rackets, but had the same Mgr/I value and they played the same timing wise.

    Oh I thought Stoneage was being ironic about the airpressure and temperature.
     
  6. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    never mind
     
    Last edited: Jan 30, 2013
  7. Midguytenis

    Midguytenis New User

    Joined:
    Dec 22, 2012
    Messages:
    66
    I have read some threads here and there for a long time, I don't have much time for forums and stuff, however this caught my eyes.

    I read through part when I could, I had 2 different rackets with completely different result that i liked, so I don't really believe this can work, different rackets, different power level.

    I also agree with someone else who posted here about swing weight, which is measured only in short distances, so when I choose a new racket (i usually play with them for 2-3 years at least) I don't base my choices on measurements at all.
     
  8. ben123

    ben123 Professional

    Joined:
    May 6, 2011
    Messages:
    1,172
    lmao learn to play tennis
     
  9. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    deleted...
     
    Last edited: Apr 30, 2013
  10. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    bump........
     
  11. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    bump......
     
  12. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    DH,
    I replied to your challenge message post and left a number.
    give me a call if you're in Seattle and this week and want to set something up.
     
  13. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Hi travlerajm. I was only in Seattle for the week. I thought I could fit a game in against you, but I didn't hear back from you until too late.

    Could you look at my questions please? Sorry for the volume of questions.
     
    Last edited: May 13, 2013
  14. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    1) Arm length varies in people of the same height. So, should everybody find there own personal mgr/i?

    2) Some rackets claim to have increased air resistance. Does this affect mgr/i? Should you re-tune mgr/i for a new racket?

    3) What if you wore the wristband further up the arm, so that it wasn't affecting the pivot point of the wrist? Would it affect mgr/i?

    4) Is the 0.2 wristband calculation based on large wristbands? I wear a small, single wide wrist band.

    5) Are you still planning on publishing a book on mgr/i?

    6) Should you use your correct grip size for mgr/i? I think you are supposed to play with a relaxed wrist for mgr/i. This seems at odds with a smaller grip-size, which is about using more wrist.

    From what I've read on smaller grips, they improve spin and spin serves, but reduce shot consistency, volleys and flat serves.
     
  15. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    Yes.
    I doubt it.
    Yes.
    If you wear a wristband near your elbow, I doubt that it would make much difference.
    The one I tested was medium - I suggest you try your own experiment.
    Yes, but I am more focused on my medical device startup for now. The tennis racquet customization book probably won't happen until I have more free time.
    I think everyone should use a grip size that feels most comfortable and relaxed.
    Again, my opinion is that a grip size that feels most comfortable will be best for all-around performance. If the grip is too small, you may fatigue your wrist by needing to grip too tightly. Same problem if it's too big to hold securely. I have smaller than average hands (9" pinkie to thumb full stretch, 7-1/2" base of palm to tip), but prefer grips in the 4-1/2 to 4-5/8 range.
     
    Last edited: Feb 2, 2013
  16. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    You doubt that the some rackets have increased air resistance, or you doubt that air resistance affects mgr/i?

    Is it true that if your mgr/i is tuned, you hit the ball with a more relaxed wrist? I thought using more wrist enhanced spin.
     
    Last edited: Feb 2, 2013
  17. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I have some final questions on lead placement:

    1) I've noticed you recommend 1/4 inch lead tape. Is 1/2" lead tape okay at 7 inches? Will this affect dynamic stiffness/spin?

    2) Lead tape under or over the grip, at 7 inches, increases the grip size. Do you place lead inside the handle?

    3) Does hand size affect mgr/i?
     
    Last edited: Apr 30, 2013
  18. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    I doubt that a difference in air resistance between racquets would have much effect on the optimum MgR/I value.
    Yes - the whole idea with optimizing MgR/I is that it allows you to hit the ball without needing to use the wrist muscles to control the angle of your racquetface as you come through the hitting zone. The racquetface of a perfectly tuned racquet will stay aligned toward your target longer. Thus, the perfectly tuned racquet is more accurate because your swing will be less sensitive to small errors in timing.

    Also, you can take advantage of a much higher swingweight racquet if it is properly tuned because your forearm will not get tired if you don't need to exert those muscles. And it is much easier to hit a heavy ball with a lot of spin if you use a higher swingweight racquet that is well-tuned.


    It doesn't matter what width of tape you use. It just matters how much mass you use and where you put it.
    I try to avoid putting lead inside, since it's more difficult to change later. If I need to add a lot of lead, if possible I use the lead to sculpt the upper part of the handle so that the grip profile shape is extended up longer for good feel on the 2hb. If the placement needs to be lower on the handle, then I spread it as thinly as possible. There is some art to it.
    If you have bigger hands, you will have more mass effectively added to the grip. So someone with very large hands might have a lower optimum MgR/I value than someone with very small hands, all else being equal.
     
    Last edited: Feb 2, 2013
  19. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    So you don't need to rotate your wrist, like rafa , to increase spin?

    Is it okay to use 1/2" lead tape rising form 7" up to 7.5"? Will this affect dynamic stiffness/spin? If not, how high can I go without affecting dynamic stiffness/spin?

    Anyway, I'm off now. Thanks for answering my many questions.
     
  20. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    Your wrist will naturally rotate effortlessly to generate the spin if your racquet is tuned for it.
    Any amount of weight added anywhere will affect the dynamic stiffness and spin. It is up to you to experiment and find what you like best.
     
    Last edited: Feb 2, 2013
  21. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    So the belief that a smaller grip increases wrist flexion, rotation and pronation, which increases spin, is wrong?
    I'm sure I remember reading a post where you said lead at 9" increases stiffness. How high can I go above 7" without affecting stiffness, to increase mgr/i?

    What is your views on racket technologies? Is an increase in power/sweetspot even a good thing for a decent player, who can generate there own power? Do the Exo3 port-holes really increase power, control, sweetspot, comfort and spin?

    I have been placing all of my lead at 12' to decrease mgr/i. Should I be adding some at 10/2, 3/9 etc?

    Does muscle strength/ fast twitch muscle fiber's have an effect of mgr/i? This is based on the belief that a person with the same muscle mass can have more muscle strength/more fast twitch type muscles.

    The wrist is pretty heavy and people differ in wrist's mass substantially. What about wide vs narrow wrists? Add to this people of the same height can have different arm length/hand size. I'm not sure you should be advising people there is an optimal mgr/i per height. I think you should advise everyone to find their own personal mgr/i.
     
    Last edited: Feb 10, 2013
  22. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    never mind
     
    Last edited: Feb 10, 2013
  23. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    Some players might prefer small grips. If they feel it gives them more spin, maybe it does.
    Adding mass at either location will increase dynamic stiffness. But adding mass at 9" will increase dynamic stiffness much more than adding mass at 7".
    I think increasing the sweetspot is always a good thing. But I don't think O-ports of exo-ports make much difference in sweetspot size - instead they just increase the effective size of the stringbed. I string tighter to compensate.
    If you want, sure. I prefer extra mass spread out around the entire upper half of the hoop.
    MgR/I has nothing to do with strength or fast twitch fibers.
    I do advise people to find their own personal optimum MgR/I value. I refer again to this post:

    http://tt.tennis-warehouse.com/showpost.php?p=5859118&postcount=17
     
    Last edited: Feb 2, 2013
  24. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Edit: I found an answer using the search function.
     
    Last edited: Apr 30, 2013
  25. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Again, I found an answer using the search function.
     
    Last edited: Feb 10, 2013
  26. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    deleted...
     
    Last edited: Apr 30, 2013
  27. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Sorry, what does "increase the effective size of the stringbed" mean?
    Could you include this link in your OP?
    I've noticed some people on here think MgR/I=21 is optimal, instead of fine tuning their racket. I assume these people have just read the OP, not the entire thread.

    What about if you wear it midarm/forearm? Would it affect Mgr/I?I moved my wristband up to midarm and noticed a difference in swingspeed.

    I think weightlifting increases hand and wrist muscle mass. Should mgr/i be re-tuned if you lift weights?
     
  28. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    The region of stringbed deflection on O3 frames extends to the outer edge of the frame. With conventional frames, the region only goes to the grommet, which are on the inside of the frame. I suppose this does increase sweet spot a tad, but also means you need to string tighter to compensate.
    Ok, I can do that.
    I don't know how much it would affect timing - I have never tried that.
    If you are Bruce Banner, then I suppose you should re-tune your racquet after you transform into your alter ego.
     
    Last edited: Feb 10, 2013
  29. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Ok, that's all. Thanks for all your help, travlerajm.
     
    Last edited: Feb 11, 2013
  30. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I've tried to tune my racket on three separate occasions now, for a sum total of 4.5hrs. Unfortunately I got nowhere. My shot's were going to the right, to the left and exactly where I wanted. I've also tried tuning by height and it didn't improve my accuracy. Maybe I have abnormally large arms, like djokovic. It would be great if we could sort MgR/I by arm/torso length. Although, that would take a large focus group and lots of money to pay them.

    It's frustrating as I now am back to the interminable demoing racket's process. It's also frustrating, as I had planned some experiments. These were:

    1) Test how switching from eastern to a extreme eastern, and SW, grip impacts MgR/I?
    2) Test the effect of wristband location. I was going to check at the elbow, upper forearm, lower forearm and at the wrist.
    3) Test the impact of choking down the handle. I was going to check a 0.5 inch movement, then 1" and finally 2 inches.

    Anyway, although MgR/I was a failure for me, I'm nerdy enough to stil have some questions on it.

    This thread suggests the racket face should be closed by 10 degrees for optimal top spin. Does MgR/I impact whether the racket is closed/open at impact?

    You have told me that muscle mass doesn't affect MgR/I much. If you went from skinny guy to Arnie (not that I intend to), how much would the MgR/i change? Does leg and torso mass/length have an impact?

    Sorry for the constant questions. I'm just trying to further understanding of MgR/i.
     
    Last edited: Apr 11, 2013
  31. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I've edited my last post to add some questions and info.
     
  32. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    If you are having difficulty tuning against the wall, remember that you need to fully relax the wrist in order to tune.

    Another way to tune MgR/I (albeit a little rougher) is to swing the racquet in your living room through a big high-to-low-to-high pendulum sweep, using your normal weight transfer as if you are hitting a forehand (but with a golf style swingpath).

    The thing to look for is what type of couple you feel the handle applying to your hand as your racquet passes through the low point of the arc.

    If you feel the handle pressing against the base knuckle of your index finger, that means MgR/I is too low. Conversely, if you feel the handle pulling forward on the distal portion of your fingers, then MgR/I is too high.

    If MgR/I is perfect, you will not feel any torque acting in either direction on your hand. You may find it useful to experiment with choking up (which will increase MgR/I) and choking down (which will lower it) in order to feel the different types of torque. For any racquet, there exists a certain hand position along the handle where the torque is zero (where MgR/I is optimized).
     
    Last edited: Apr 11, 2013
  33. mykoh

    mykoh Rookie

    Joined:
    Jun 22, 2012
    Messages:
    383
    awesome stuff trav.

    any particular grip required when you do this? or do you hold your normal forehand grip (SW for me)?
     
  34. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I was fully relaxing my wrist throughout the wall test's. My shot's were going to the right, left and exactly where I intended.
    I tried the rough method. I could feel the racket pressing against the knuckles. Unfortunately, no matter how much lead I added at 7", I couldn't feel the handle pulling forward on the distal portion of the fingers. I tried swinging quickly and slowly.
    My aim with experimenting on choking down the handle was to get an exact number of how much choking down affects MgR/I. If we can work out how much different equipment factors affect MgR/I, then people don't have to return to the practice wall every time they make a change.

    With most of these questions I could have found out the answers for myself, but I got nowhere with the wall tuning. Thanks muchly for answering my questions.
     
    Last edited: May 13, 2013
  35. mykoh

    mykoh Rookie

    Joined:
    Jun 22, 2012
    Messages:
    383
    You are one curious dude
     
  36. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Bump. I must start posting my questions in american time, since this is predominantly an american forum. Starting from now I will do this.
     
  37. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Last bump then I'll give up.
     
  38. Relinquis

    Relinquis Hall of Fame

    Joined:
    Dec 12, 2012
    Messages:
    4,335
    Location:
    On the courts; hard & clay ...
    no you won't...
     
  39. BlueB

    BlueB Hall of Fame

    Joined:
    Jun 18, 2012
    Messages:
    1,772
    Location:
    Vancouver, BC
    Just a recent observation of mine...
    While I'm not a firm believer in this theory, I keep this information in the spread sheet of my racquets' specs and mods. I noticed something interesting and re-confirmed it today by adding and reducing weight from a specific point on the racquet while playing/serving. The balance optimised for groundie forheand constantly served worse then the one that had 0.2 lesser MgR/I.
    Anyone else noticed this?
    Anyone worked on optimal numbers for serve?
     
  40. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    Optimization for serve is complex - it depends not only on the the swing dynamics, but on the hitting weight and dynamic stiffness as well. If you tell me the two sets of specs you are comparing (and what point on the racquet you were adding/reducing weight), I might be able to shed some insight on why one was better than the other.
     
    Last edited: May 20, 2013
  41. BlueB

    BlueB Hall of Fame

    Joined:
    Jun 18, 2012
    Messages:
    1,772
    Location:
    Vancouver, BC
    Setup 1 (the one that served better)
    W 326g, Bal 32.9cm, SW 323, MgR/I 20.82

    Setup 2
    W 334g, Bal 32.6cm, SW 324, MgR/I 20.99

    Difference was 8g at 20cm.
     
  42. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,438
    Without knowing exactly what you mean by "served better", I can take guesses.

    You mean either:
    A. More spin.
    B. More power.

    If A: If the racquet has some flex to it, then adding 8g at 20cm from the butt will tend to increase the dynamic stiffness. This might be noticed as a decrease in spin or bite on the serve. The more flexible the frame, the more significant this effect.

    But if the frame is rather stiff to begin with, then the dynamic stiffness wouldn't be affected that much by 8g at 20cm.

    If B: For a given swingweight and static weight, there is an optimum balance that gives maximum effective mass. The smaller the 'delta' between that optimum balance and the actual balance, the sweeter and more "power efficient" the racquet will feel on the serve.

    Adding the 8g of mass at 20cm to the first racquet increased the 'delta' from about 4mm to about 5mm, which would tend to reduce the "power efficiency" on the serve. In my experience, increasing this delta usually means that the increase in effective mass by adding the mass does not overcome the reduction in racquet speed.

    That being said, it's important to note that this "optimum balance" for serves is not nearly as important as optimizing the swingweight. I'm currently using a frame with delta of ~2.5mm. For most players using a standard length midplus frame, the optimum swingweight for maximum serve velocity is between 350 and 370. That is, adding mass to the hoop of most stock frames will make the racquet serve better for most players. Or if you have a lot of arm strength, the optimum may be higher than that. The optimum SW is also a function of racquet length. The optimum swingweight for an extended frame is higher than for a standard length frame.
     
    Last edited: May 21, 2013
  43. Yevgeny2010

    Yevgeny2010 New User

    Joined:
    Aug 29, 2010
    Messages:
    46
    Location:
    Australia
    Trav, thanks for all your hard work and experimentation on these performance formulas, they seem to be part of the missing glue which allows us to customise our racket to the same "feel". I say "feel" because SW, Balance and Static Weight are good indicators, but I think your MgR/I formula binds them all together and gives us something to compare mutliple rackets with potentially different specs. Sometimes you just don't have quality controlled factory duplicates like the pro's get, so you gotta work with different specs. That's where I see the benefit of your work. Even when moving across different brands of rackets.

    This ability to compare the feel of multiple rackets is very helpful to me and I guess many others here. It makes some sense but I won't pretend to understand the theory, except that most of the things you've noticed in coming up with these ideas match what I have observed too.

    Whether this is regression modelling or a proven, scientifically valid discovery, I don't really care and I won't insist on seeing any double blind studies or scientific journal entries, as do some of the others on this board. People got to remember anything on these boards in someon's opinions, so when Trav says something doesn't mean he's proven it beyond a reasonable doudt. I'd say chill out to some of those people.

    Also, the fact that customised (or stock) extended length rackets are used by a lot of pro's on your list would need to be considered in the whole equation, which I think doesn't happen now. For example, longer rackets may need greater SW than standard length in order to feel solid. I would be interested to see some segregation of data based on racket length, then it would be truly useful, moreso than grip size, atmosphere or wristbands etc. Those other items can be experimented by users, but racket length needs to be built into the formulas and "ideal ranges" need to be separated by racket length.

    To the naysayers, I ask them if there is comparable documentary evidence that someone else (eg Rod Cross) has come up with such a useful formula and approach, I own a few of his more technical books and I've yet to see anything fresh I can use on a daily basis to help with customisation. He's making so many assumptions and basing tests on bolted down rackets that I doubt the results translate to real life situations.

    I find Trav's ideas are helpful in these situations, so thanks Trav.
     
  44. Yevgeny2010

    Yevgeny2010 New User

    Joined:
    Aug 29, 2010
    Messages:
    46
    Location:
    Australia
    Laymans method of determining best MgR/I for you?

    Trav, I had a few situations where I was playing some of my best tennis and noticed when the racket is tuned for my style that something on the 2HBH is apparent and happening each time the setup is at my ideal.

    Some background first. Unlike previous posters, I seem to prefer tuning the racket for my 2HBH first and then making minor adjustments for the forehand if necessary, as the forehand can always be whipped a bit faster and adjusted during swingtime quite easily. Therefore my forehand is less sensitive to timing errors and racket balance because my dominant hand is in control and I have more micro control on that side and better timing.

    The 2HBH is a more powerful and brute shot with less control and seems to be sensitive to MgR/I being too low or too high. I can't adjust the 2HBH as easily to cater for minor imbalances in the racket since my non-dominant hand is involved and simply provides the power. Adjusting the 2HBH during swingtime leads to all sorts of strange wrist movements and handling issues with both hands involved. If SW is too high, I end up holding on to the racket for too long with my non-dominant hand and wristing the ball to guide it. If SW is too low I end up pushing the racket too much with my non-dominant hand to get some power and overshoot the baseline quite a lot with excess power.

    Ok then, when things are tuned I notice my 2HBH swing is very relaxed with both hands applying equal force on the racket rather than one hand pushing or pulling to adjust the swing. Also, more importantly I find that during the final part of the swing I can almost just let the racket go with my non-dominant hand and it will float nicely around over my should, even spinning a little in my dominant hand to offload the energy at the end of the swing. I was quite amazed at this feeling, because you see some of the pro's doing that spin at the end of their 2HBH and now I think I know why. It's probably means the kinetic chain is working efficiently and the racket is moving at a constant and even path through the 2HBH and nothing more is require by you except to enjoy that feeling.

    Basically, I tried a lot of tuning with Travs formulas, but I think you first need to set the Swingweight to your desired setting (using above guideline) and then record the MgR/I result, using both SW and MgR/I next time to fine tune different rackets. SW and Balance by themselves are simply not enough, you need to account for MgR/I as well.

    I suspect the reason the Wilson customisation rooms don't make such a fuss about this type of tuning is because most rackets given to the pros come out pretty similar and just need to be adjusted for SW and Balance. But for anyone else I'm guessing the Trav formulas may help to tune multiple rackets to your particular style.

    Has anyone had the same experience?
     
  45. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    Yevgeny, are you aware that travlerajm has a separate formula for optimising the 2hb?
     
  46. Yevgeny2010

    Yevgeny2010 New User

    Joined:
    Aug 29, 2010
    Messages:
    46
    Location:
    Australia
    NewYork, I tried using that backhand formula Mg(R-10)/(SW) but found it did not work as expected, for me at least. Tuning to this formula assumes your axis of rotation is 10 cm higher on the 2HBH but I suspect that may not be the case with various types of 2HBH's. Those who power with the non-dominant hand and simple pivot around the dominant hand may work well, but those who use equal force on both hands during a 2HBH (or use longer rackets) may do better tuning with the original formula as I did, as the axis of rotation hasn't changed that much. Not sure if I'm explaining that clearly, but some people treat a 2HBH as an opposite side forehand while others like Jimmy Connors use equal power on both hands more like a 1HBH.

    I've found that Trav's suggestion for tuning to the forehand first and then adding lead to the buttcap to adjust for the 2HBH doesn't work for me. I'd rather tune the MgR/I perfectly to the backhand first and then adjust for the forehand with lead at various locations. Then I calculate the backhand Mg(R-10)/(SW) which may end up a little different on both rackets. As I said previously these formulas are guidelines for tuning multiple rackets and I use them as checkpoints to verify the feel of the swing is the same for me, given my style of strokes, which may be different for others.

    I still think racket length plays a major role here, with SW being higher and optimal ranges being different, so I may be in a different boat to others. With many of the pro's using extended rackets I would think a sub-analysis of the data based on racket length is the next step of this discovery process.
     
  47. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I know very little about the 2hbh as I've never used one. Maybe travlerajm will chime in on this. There is definitely still a lot to learn about MgR/I, some of which I'm trying to find out through experimentation and wall tuning.
     
  48. Maroon_Tenniskid

    Maroon_Tenniskid Semi-Pro

    Joined:
    Jan 8, 2011
    Messages:
    628
    So I got my numbers.

    Mass: 330.3g

    Balance Pt.: 32.54375 cm

    Swingweight: 328

    MR^2:349.8196088

    Moment of Inertia: 509.9541743

    MgR/I: 20.66774058

    I'm just a little thrown off on how to modify my racket to get the MgR/I near 21.0

    Anybody want to help me out? I'm 5'11" and have a 2hbh by the way.
     
  49. newyorkstadium

    newyorkstadium Semi-Pro

    Joined:
    Jan 12, 2012
    Messages:
    585
    I will. I'm busy for the rest of today, but I will post the details tomorrow, if someone hasn't already.
     
  50. Maroon_Tenniskid

    Maroon_Tenniskid Semi-Pro

    Joined:
    Jan 8, 2011
    Messages:
    628
    Cool thanks! I have lead ready to go I just need to know where to put it and how much :p now time to do physics homework ironically.
     

Share This Page