The Official Lead Tape Placement+Racket Customization Thread

Discussion in 'Racquets' started by xFullCourtTenniSx, Jan 29, 2010.

  1. Irvin

    Irvin G.O.A.T.

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    No problem here it is
    I'm not done with experimenting on this quite yet @zalive. You say you still don't understand how some can say the racket is slowing down. Well believe it or not I still can. I think it all depends on your point of reference. It's all about the distance from the axis to the center of mass and where you add the weight. The period is dependent on two things the distance from the axis to the center of mass and the inertia (aka Recoil Weight.)

    You're saying the racket is whipper because you probably have a loose grip and whip the head through the ball because the distance from the COM to the axis is much shorter than is you had a tight grip.
     
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  2. Irvin

    Irvin G.O.A.T.

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    One more thing I must say, although the experiment proves the racket speed up when I added mass at 7" I used a known axis of 10 cm. It is virtually impossible to swing a racket on a 10 cm axis. Therefore because the speed of the racket is dependent on the distance from the axis to the COM this experiment has led me to a lot of unanswered questions in my mind.
     
  3. Shroud

    Shroud Legend

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    Fwiw i think Ranchdressing had a great video on MgR/I and explains how it might not work for some people though i know you are not a fan i think the vid deserves some attention.

    Anyhow thanks for the experiment and confirmation. Kind of counterintuitive that adding weight can speed things up. I have often wondered why guys cant seem to use high swing weights like I am but ifthe racquet is modded right it looks like a higher SW can be manageable. This is a boon i think for the rec player willing to spend some time with lead.

    Fwiw i have to add more than 10gs at 7" and always end up around 30g. I tune by feel and its what it usally comes out to.

     
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  4. Irvin

    Irvin G.O.A.T.

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    I think some are missing some very key concepts. First of all is gravity. gravity is nature's constant pull machine. As long as the altitude is the same the pull of gravity is the same no matter what the mass is. Gravity can move mountains (avalanche) and gravity can pull a softball back down from high peaks. If it were not for air friction gravity would pull a bowling ball down as fast as it would pull a balloon. But because there is not enough mass in the balloon the air friction slows it down so it does not fall as fast. In a vacuum they both fall at the same speed. But mass adds something into the equation. If bowing ball and a balloon were both traveling at the same speed I would rather be hit with a balloon than a 16 lb bowling ball. If you have a 16 lb bowling ball and an 8 lb bowling ball which is easier to throw?

    Let's move on to a pendulum. In a simple pendulum a bob is suspended on a string and no matter how much the bob weights if I can negate air friction a bob travels at the same speed or period no matter how much t weighs. The period of a pendulum is directly proportionate to the length of the string. The shorter the string the shorter the period, and the longer the string the longer the period. So if I took a baseball suspended from a 10' string and a wrecking ball suspended from a 10' chain the periods of the two would be about the same. Which one would your rather stop?

    Now let's get back to my experiment. The racket traveled fast when I added weight because the COM was moved closer to the pivot when I added mass between the pivot and the COM lowering the COM. The period did not get faster because I added mass, it got faster because I moved the COM.

    There there is force, the force (in this discussion tongue or SW) goes up.
     
  5. Irvin

    Irvin G.O.A.T.

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    More on that 7" mark. I've been thinking about it and I think the reason the racket sped up is just because I moved the center of mass closer to the axis and only increased the inertia a very small amount. Inertia around the axis and the distance from the axis to COM are the only two things are affect speed when resisting gravity. SW affects speed when you swing a racket. I think if I move the 10 g of mass to 3" on the other side of the axis 1" from the butt the inertia change around the axis @ 10 cm will be the same (7.75 cm x 7.75 cm x .01 kg) but the center of mass will move even closer to the axis and the period will be shorter. @zalive @Shroud what do you think? If you're going to add weight, since the real axis for a swing is somewhere below the butt of the racket, the lower you can place any weight the lower the COM will be, the lower the inertia will be, and the faster you can swing the racket, if you're going to add weight.
     
    Last edited: Jan 29, 2017
  6. elkabras

    elkabras New User

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    I' m searching for best config for a Biomimetic 300 Tour....no more 340 gr strung...leather grip...where would you put the lead tape?

    Enviado desde mi Redmi Note 3 mediante Tapatalk
     
  7. tennisbike

    tennisbike New User

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    Off topic on technical discussion but...

    I did some reading and research on this topic and kind of gave up and just went ahead and modified my recently acquired Babolat Pure Storm Tour GT+. A little background: The Pure Storm felt good when I picked it up, felt familiar like the wooden rackets that I grew up playing. But the first session with new string at 320 g felt lack of power and unstable (twisting). Disappointed I put 6 inch of 1/4" lead tape along 3 and 9 o'clock to add stability then lastly 2 nickels with the grip elastic band just above the hand position on the grip. This increased the static weight to 350g. Let me tell you ... Magic happened.

    I thought a good racket can Maximize a player's ability, allowing the player to play to his highest level.

    The racket did more. Not only the power increased. The ball popped off the string bed easily with no added effort. It was power but controlled power. The volley became insanely easy. I felt like a wall at the net, a short wall. I hit shots well, that I never even tried or practice, like an backhand overhead, or a slice high forehand, more like a slap. A full stretch backhand volley, dropping the ball cross cross court... The racket made me felt as if the RF programming was downloaded onto me in Matrix. The racket actually EXTENDED my ability, It was surreal. (My blog entry: http://tennislaboratory.blogspot.com/2017/01/magic-stick.html)

    The only actual numerical goal I had was 350 g, matching from my previous favorite stick. The other 6" x 4 1/4" lead tape and 2 nickels idea came from reading in talk tennis. Yes, I got lucky in one trial. But all the number aside, I suggest just try whatever setting you had in mind and see how it plays. It is a trial and error process.
     
  8. tennisbike

    tennisbike New User

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    Off topic on technical discussion but...

    I did some reading and research on this topic and kind of gave up and just went ahead and modified my recently acquired Babolat Pure Storm Tour GT+. A little background: The Pure Storm felt good when I picked it up, felt familiar like the wooden rackets that I grew up playing. But the first session with new string at 320 g felt lack of power and unstable (twisting). Disappointed I put 6 inch of 1/4" lead tape along 3 and 9 o'clock to add stability then lastly 2 nickels with the grip elastic band just above the hand position on the grip. This increased the static weight to 350g. Let me tell you ... Magic happened.

    I thought a good racket can Maximize a player's ability, allowing the player to play to his highest level.

    The racket did more. Not only the power increased. The ball popped off the string bed easily with no added effort. It was power but controlled power. The volley became insanely easy. I felt like a wall at the net, a short wall. I hit shots well, that I never even tried or practice, like an backhand overhead, or a slice high forehand, more like a slap. A full stretch backhand volley, dropping the ball cross cross court... The racket made me felt as if the RF programming was downloaded onto me in Matrix. The racket actually EXTENDED my ability, It was surreal. (My blog entry: http://tennislaboratory.blogspot.com/2017/01/magic-stick.html)

    The only actual numerical goal I had was 350 g, matching from my previous favorite stick. The other 6" x 4 1/4" lead tape and 2 nickels idea came from reading in talk tennis. Yes, I got lucky in one trial. But all the number aside, I suggest just try whatever setting you had in mind and see how it plays. It is a trial and error process.
     
  9. zalive

    zalive Hall of Fame

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    But MgR/I theory (or at least understanding of it) says racquet will become faster (as a pendulum) as long as MgR/I is increasing.
    And you can increase MgR/I even if you put mass at the lower hoop, which actually moves away COM from the pivot point (if balance is head light). With biggest effect in MgR/I increase being if mass is added at 6 o'clock.
    So feel free to try the same experiment (measuring of period) with adding mass to 6 o'clock - you can use a dampener placed right next to the frame at 6 o'clock.
     
    Last edited: Jan 29, 2017
  10. zalive

    zalive Hall of Fame

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    double post
     
  11. Shroud

    Shroud Legend

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    Mu 2 cents is its like popcorn. As dennis Miller says who cares why it pops, it just does! I dont have time to figure it out but i do have time to implement the theory and get my racquet to feel great.

    Also if i think i understand what you are saying why not put mass outside the butt cap? I have done that on a few sticks but for some reason placing the weight at 7" makes it speed up more than the same weight on yhe outside of the buttcap. You can do this easily with blutak or poster putty.
     
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  12. Josh W

    Josh W New User

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    This may be the wrong place for this, but I am currently using the one gen old Prestige Pro (bright orange and black) with some lead tape in the throat and handle, and am demoing the new Prestige pro. With the same amount of lead tape in the same exact spots, I still found myself adding a ton of lead tape to the tip of the new frame in addition because it was so power deprived, unlike my old one. Now I get the power, but the racket's feel is completely different (and worse). Is there a reason for this or am I just crazy? Is there any way to sort of increase the feel without changing the specs too much? Also, does anyone know why the new Prestige pro has so much less power even though the specs are very similar to the one I'm using now? I assume it's because of a different weight distribution, but on different reviews people have concluded that it still has a pretty polarized setup like my other one. Thank you in advance.
     
  13. zalive

    zalive Hall of Fame

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    You need some lead tape at either 7'' from the butt under the grip, or under the throat. Also at 6 o'clock is a possibility. Anyway, what's important: adding lead to the tip makes a racquet slower through swing because it slows down pendulum (racquet is a pendulum). Also, you move the sweet spot a lot towards the tip - the effect can subjectively be likeable to a certain player, but it can also be horrid. You can even create a hot spot in certain situations which you don't want. In this case lead at 6 o'clock can help to move the sweet spot a bit back, but it corrects MgR/I at the same time (which is responsible for swing speed). You have the thread about MgR/I.
     
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  14. Josh W

    Josh W New User

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    Thank you!
     
  15. LeftyJunk

    LeftyJunk New User

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    Suggestions please! I wanted to increase the stability of my Pure Strike (the old model) so I currently have four grams split up at 3 and 9 on the hoop as a starting point. I like the balance of the racquet so where on the handle should I counter that with another four grams? Also is a total of eight grams even worth my time meaning should I start with more?!
     
  16. tennisreflectslife

    tennisreflectslife New User

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    U shud be able to feel some benefit of 4 gms at 3 and 9, if not try 6 gms. As for counter weight, it depends on how much headlight balance and total weight u want. u can decide where to add the lead on handle based on that.If u want most headlight then add to the very bottom.
     
  17. Irvin

    Irvin G.O.A.T.

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    No matter what your racket weighs or where your balance point is if you add 8 g 20 cm above the balance point you can add the same weight the same distance below the balance point. If it balance when you started it will have the same balance after. Another option is the product of the mass 8 g) and distance (20 cm) must be the same above and below. If you add 8 g x 20 cm or 160 gcm above you must add 120 gcm below. It does not matter if it is 12 g at 10 cm, 10 at 12 cm, 4 g at 30 cm, etc...

    The only time when the original weight and balance must be known is when you want to move the balance a certain distance. Adding 8 g at 3&9 will move the balance that is a given but how far depend on the racket's original balance, how far above the balance point 3&9 is, and the original weight of the frame.

    The real question is do you really think you want to keep the original balance point? Adding an overwrap to a racket has about the same change in balance (or more) than adding 8 g at 3&9.
     
  18. LeftyJunk

    LeftyJunk New User

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    Awesome response! This definitely makes sense... I will tinker before I head off to the courts tonight. Thank you!
     
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  19. zalive

    zalive Hall of Fame

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    Excellent point.
    I think, when players mention balance, they actually mean how racquet feels when they swing it.
     
  20. Irvin

    Irvin G.O.A.T.

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    Could not agree more. Swing weight determines how the racket feels when they swing it. For example, the Inertia of a racket (what it feel like to swing it) always goes up when you add weight. And because because the Inertia goes up it requires more force to swing the racket. Let's assume we have a racket:

    Weight 320 g - Balance 33 cm - Swing Weight 320. This means this racket has Inertia at the center of mass (Icm) of 179. But no one swings a racket at the 10 cm SW axis or around the CM. The pivot point is somewhere below the butt of the racket. Look at what happen when you add 8 g of mass at 53 cm (3&9.)

    Icm +3.2 / I @ SW +14.8 / I @ butt +22.5 / I @ -10 cm 31.8

    When you add 8 g 20 cm below 33 cm poin (13 cm):

    Icm +3.2 / I @ SW +0.1 / I @ butt +1.4 / I @ -10 cm 4.2

    Every bit of mass is additive and no matter where you add it the racket requires more force to swing it. The farther the mass is from the CM the greater the Icm, the farther the mass is from 10 cm the greater the SW, but no matter where it is the racket is harder to swing.
     
  21. Irvin

    Irvin G.O.A.T.

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    Here is another point some people don't think about. If you want to increase you stability why not add to the grip? Adding lead to the top and bottom bevels of the pallet will give you greater leverage on off center shots and at the same time not greatly increase the force required to when compared to adding mass to the head of the racket. Maybe you need/want a more rectangular pallet.
     
    Last edited: Feb 9, 2017
  22. LeftyJunk

    LeftyJunk New User

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    So what would be a good starting point (in grams) for this? And where on the handle? Such as closer to the butt-cap or throat...
     
    Last edited: Feb 9, 2017
  23. Irvin

    Irvin G.O.A.T.

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    I really believe any mass you add to the handle is going to increase the force required to swing it so I'd be a little afraid to make a suggestion in grams for you. I like the added weight to my stock frames but maybe you would not. If you question is about adding something to the top and bottom bevels you could start with something like cardboard (not corrugated,) or strips of tape, or even something heavier like 1/2" lead tape. You want it to extend the length of your grip so how long it is depend on if you have a 1/2 hand backhand. I went from the top of butt cap (where it meets the pallet) to the top of the pallet and love it.
     
    Last edited: Feb 9, 2017
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  24. nytennisaddict

    nytennisaddict Hall of Fame

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    as you guys increase the mass, do you find you tend to increase your string tension as well?
    i added about 50g, still headlight, and love the plough-through i get... but now i feel i need to increase tension slightly (ie. from say 45lbs -> 55lbs)
     
  25. CodyZzZ

    CodyZzZ New User

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    I do that to a certain extend. Usually we do it because adding mass increases swingweight, which means more power. It makes sense for people to compensate that increase in power with higher tension to regain the lowered control. In your case, 50g seems quite a lot, so not surprising you have to increase tension to better manage the swingweight.

    I do feel however that if you find yourself increasing tension by too much (over 60lbs w/ poly), it probably means your technique is not ready for the high swingweight. : (
     
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  26. Shroud

    Shroud Legend

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    Exactly!! Thats why i am using 86lbs! With my normal racquets like the profile you can still get power and need to string high to control. That was a problem i had on sunday because the sw was low but tension was still high...no power
     
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  27. Soundmouse

    Soundmouse New User

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    Hey, I would like to ask for some advices as someone who's totally new to racquet tuning.

    I have an old APD (2011 ) that I do not want to get rid of or stop using for multiples reasons, but ever since I've made the switch to the RF97 I find it to be really unstable and lacking plow through, to the point that each time I've tried to use it I had to go back after 5 minutes .

    Where would you advise to place some lead at to increase both the plow through, stability to some extent and without having to re-grip? Looking at the first page the 'Depolarized' Setup with lead at 3&9 or 12 seems to be what I'm looking for, but wouldn't the lack of added weight on the handle in my case render the whole thing pretty useless?

    Thanks!
     
  28. CodyZzZ

    CodyZzZ New User

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    It wouldnt be useless, just more head-heavy than what it already is. You'll still be able to get to RF97's SW, but the APD will feel less maneuverable. See if that works. Aware you don't want to tweak the handle, I would however still reccomend it. You'll get it closer to RF97's static weight and balance as an added benefit too.
     
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  29. saleem

    saleem Rookie

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    babolat rackets have trap door on the butt cap, add weight to 3-9 (6grams) and 12 (2grams), add 16 grams inside the trap door and that should do the trick.
     
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  30. Crie

    Crie Rookie

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    How much layers of lead tape you think you can add under the bumper before it starts to affect the racquet? 3? 2?
     
  31. Shroud

    Shroud Legend

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    Think i managed 4 once
     
  32. zalive

    zalive Hall of Fame

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    You used to use a 110'' racquet, you don't need such tension on a typical midplus, say, 97-98''. So with a Profile you need much, much lower tension to get power. Your tension experience with your Wilson BLX won't be much of use here.
     
  33. Shroud

    Shroud Legend

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    One would think. But i find the sw is the same or are least i shoot for the same weight and balance with the smaller headed racquets and the power is comparable. Also i could never get the 110" tight enough so this is great in the 95"

    Fwiw i do drop the crosses a bit on the profiles i think or at least some of them i do

    The racquet in question was the steam 96. That racquet is the lowest powered racquet i have ever used!!! I never added all the weight i did to the other racquets but it was ridiculosly low powered.

    Long story but i depolarized it recently and the sw isnt as high as the polarized version. Its still 380g but low sw. I added 32g at aprox 11" from the buttcap and 10g total at 3&9. I also shortened it. So less power vs my other racquets. Need to tweak it with more lead and i plan to redo the crosses at lower tension.

    My preference though would be to just add mass and keep the tension high. But this is a serve and volley racquet so maybe some ball pocketing is in order???

    Anyhow for them most part power is not an issue and control is. I mistakenly believed that precision would be more important in serve and volley tennis but i found Nytennisadict was returning too well off my now slower serves....
     
  34. prjacobs

    prjacobs Hall of Fame

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    You might want to use tungsten. It weighs more so you can use less.


    Sent from my iPad using Tapatalk
     
  35. Crie

    Crie Rookie

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    Its thicker and you can't put it under the bumper :(
     
  36. Soundmouse

    Soundmouse New User

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    I had totally forgot babolats have a trap door, thanks! Definitely going to try out as you suggested once I get my hands on some lead tape.

    Thanks, I guess it would've been a bad idea for me to omit adding weight to the handle then since I prefer head-light rackets.

    Thanks again for the advices guys.
     
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  37. saleem

    saleem Rookie

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    use blue tack putty, tungsten putty or tungsten rubber inside the trap door, it is easier to use there.
     
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  38. Crie

    Crie Rookie

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    How mandatory is it to put lead at the 7" mark in the handle? I've always been putting it in the buttcap. Anything wrong with that @Irvin?
     
  39. zalive

    zalive Hall of Fame

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    Nothing wrong with any placement on the handle, but placing lead at 7'' or at the butt have different effects.

    When you put lead at 7'' from the butt, it speeds up the swing because it affects racquet as a pendulum and increases its period.
    It really depends on a setup whether this is useful or not. There's a thread related to MgR/I physics and there are calculations there. But anything can be tuned strictly by feel, or experience, too. After all fine tuning is strictly based on trial and observation.

    When you put very close to the butt cap, it has a neutral effect on a MgR/I and its effects - it won't speed up the swing, it won't slow it down significantly either. However it will be more beneficial for racquet stability (recoil weight), and it's much more effective as a corrector of balance towards more head light. It also corrects a static moment (7'' doesn't do this) of a racquet, resulting in a racquet that feels lighter to hold still in one hand (I think it has some beneficial effect on hitting too).

    My personal approach is to add on both spots. First I add as much as I need to compensate (I calculate the initial quantity through MgR/I formula; I fill fine tune it later after seeing how it swings and hits). And then I add the rest to the butt to achieve desired balance and feel.

    Whenever you add lead at the upper hoop, it decreases MgR/I and hence it noticeably makes a racquet harder to swing, in which case correction at 7'' is kind of wanted. It can be done at the throat too, also at 6 o'clock, but I think 7'' position is cleaner - it won't increase SW significantly and it will correct a balance some, unlike when lead is put at the throat or at the 6 o'clock.

    Setup with too low MgR/I is more energy demanding as you need to put more energy to compensate for its slower swing. Such a setup can be often felt as being tiring to play with for more than one hour.

    My personal experience tells light basic/replacement grips are the best to achieve the most whippy result, in combination with lead/putty placement at 7'' from the butt and at the butt. Light basic grips allow lot of customization room - for some reasons heavy grips like leather on a heavier setup can result in a lagging sensation. I make my best (whippiest and easiest to handle and swing in general) custom setups by using Wilson Comfort grip which has just 10-11 grams. So, while leather will simply feel unique, there is a potential gain in terms of additional whippiness when using a light synth grip and customizing with lead/mass distribution between 7'' from the butt and the butt. Results can be really surprising, as racquet may feel significanlty ligher to handle than its static weight/swing weight specs suggest.
     
    Last edited: Feb 21, 2017
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  40. Irvin

    Irvin G.O.A.T.

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    You can put weight anywhere you want to put lead. You can also just move the existing lead around if you don't want to increase the total weight. If I were customizing my rackets for total weight, SW, and balance I would not want to add more weight at 7" just to get the MgR/I where I want it. That only means my total weight, SW, and balance were off.

    Look at it this way. You can use the RacquetTune MgR/I online app to determine your MgR/I with only the hang point, balance, and period. That's because the only thing that matters in the period is the center of mass and the inertia. The closer the balance / pivot or inertia around the pivot the faster the period. The greater the balance / pivot or the Inertia around the pivot the slower the period. Adding weight at either the butt or the 7" mark (assuming the pivot is the top string or some other point above the balance point) makes the balance / pivot distance longer slowing down the period and at the same time it raises the inertia which also slows down the period. If your period is too slow to begin with you will never be able to slow it down and make it faster. So adding mass anywhere below the balance point is not going to help you achieve the speed you want.

    If you're trying to match two or more rackets and they all Weight the same why would you add weight to one and not the other. If you're doing it for MgR/I matching and the M (mass) is the same then eight your g (gravity,) R (distance from balance to pivot,) or your I (inertia) is off. I doubt gravity is you issue so the only thing left is the radius/Inertia ratio.

    So I guess my answer would be, where you add weight (butt or 7") depends on what you're trying to do.
     
  41. Irvin

    Irvin G.O.A.T.

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    Assuming you're pivoting the racket from the butt (or some point up your arm) lowers the center of mass making the Radius shorter. That will also speed up the racket. But at the same time it changes inertia. And it is difficult for most people to pivot a racket from the butt. Most people that use any home measurements swing the racket from a pivot above the center of mass like a cross swing. Any because the pivot is on the opposite side of the balance point the effect is different. Adding mass anywhere below the COM slows down the period.

    But we're talking about the change in periods where the force that controls the swing it gravity. Where the player has to swing the racket they have to overcome gravity and the higher the mass the more the player must overcome.
     
  42. Irvin

    Irvin G.O.A.T.

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    MgR/I as far as I'm concerned is counterintuitive. First you set your racket up so the mass, balance, and inertia is what you want then you go out and hit on a wall. And if the racket isn't right you can fine tune it by adding mass at 7" to speed the racket up. LOL 50% of players will have a rackets that's too slow and 50% will have a racket that is too fast. For 50% it works and they swear by it and the rest proclaim the logic is worthless. Problem is they are both right.

    If you want a racket that weighs 330 g that's easy to obtain if your racket weight less than 330 g to begin with. You add weight until the total mass is 330 g. But if you start out with a racket that weighs 335 g you can add weight until I wind all four grand slams and you will never get 330 g.

    I suggest you find something close in weight, inertia, and balance you like and measure the MgR/I. I prefer to use the RacquetTune online app to measure it swinging the racket from the top string. Then change you time until you find out how the MgR/I changes. Change the balance to see how the MgR/I changes. Once you understand how balance and inertia control the period and MgR/I you can adjust the MgR/I on your racket very easily. You don't have to hit on a wall and keep adding weight Willy Nally to try to attain something that's impossible.

    MgR/I is nothing but a ratio of balance and inertia. It's hard to believe for some but mass has nothing to do with it. But if I have two of the same rackets with the same weight, balance, and MgR/I. The Recoil weight and SW is perfectly matched too. It is highly probable that I can have two racket at the same weight +/- 0.5 g, same balance +/- 0.5 mm, and inertia +/- 0.5 point and have different periods or MgR/I. All those +s and -s add up. I prefer to keep it simple, fewer the errors but better the end result.
     
  43. Karma Tennis

    Karma Tennis Professional

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    What?

    How does adding static weight anywhere above where the hand grips the racquet speed up the swing?

    Surely, assuming the same applied force, increasing the static weight will actually slow the swing down because because of the effects of inertia.

    For example, if I have two racquets that have identical static weight but different Balance specs. Swinging both racquets with the same applied force will yield higher RHS in the racquet that is more Head Light.

    ... Or am I missing something here?

    Hang on. I see that you said "speeds up the swing". Ok, now I get it :)

    It will speed up the swing, but it will require greater applied force to get the racquet into position to take advantage of the increased swing speed. Good ole gravity at work.
     
  44. Irvin

    Irvin G.O.A.T.

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    How does adding weight speed up the swing? If a racket is suspend from the butt and allowing to pivot the closer the center of mass is to the pivot the faster it will swing. The period is only dependent on the distance from the pivot to the center of mass to the pivot and inertia not mass. Here's a simple experiment you can do. Get yourself a 10 pound sledge hammer and drill a hole very close to the end of the handle. Hang the hammer on a very sturdy nail and time the period. Now put two 25 lb weights about 1' from the end of the handle and let it swing you will notice a faster period because the balance point is now closer to the pivot.

    What some people fail to realize is that 60 lb hammer will be hard to pick up yet alone swing. You can do the same thing with a 78' railroad rail. Allow it to pivot from one end and measure the period. The center of mass is just about at the 39' mark. Add enough mass closer to the pivot to move the center of mass down to 20' and the rail with swing faster. Of course I'm ignoring the fast of how hard it is to swing. If you want to know how hard it is to swing just pick it up by the pivot end.

    FACT when you add mass to a racket no matter where you add that mass the inertia goes up and it will require more force to swing the racket in a circular motion. When you add mass inertia goes up ALWAYS ALWAYS ALWAYS.
     
  45. Irvin

    Irvin G.O.A.T.

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    If you would like to try your own little experiment get a 27" piece of 1"x2" wood. Drill a holes very close to one end and hang it on a nail. The COM should be close to even. Now you can add mass to see how it changes the period. When you add mass closer to the pivot the COM moves toward the pivot and the period speeds up. When you add mass farther from the pivot above the COM the period slows down. Simple physics, the greater the radius the longer the period.

    Assuming your SW axis is 10 cm and you add 10 g at 7" or 7.78 cm above the axis your SW goes up about 3 points. The higher the SW the more force is required to swing the racket. The higher and higher you move the Mass the greater the radius and the greater the SW.
     
  46. zalive

    zalive Hall of Fame

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    Irvin made an experiment in which he proved adding lead to 7'' shortened the swing period of a racquet when he hung the racquet as a pendulum and measured its swing period.
    He basically scientifically proved setup swung inherently faster.

    The effect of a racquet tuned for MgR/I is that when you swing it with your arm, you will increase RHS, and it will be easier and less tiring to swing it.

    It's not just gravity. It's affecting any inertia which keeps the racquet going with more ease once you swing it. So basically such racquet is easier to mainain RHS while with some setups you need to push the throttle all the time and this wears you out over time. Usually players conclude: ok, this SW is too much for me; only it wasn't about swing weight at all. It was about MgR/I.

    I've done my custom setups with MgR/I tuned closer to value of 21 (I don't have accurate enough measurements to confirm if this is really accurately 21, but I tuned each not to be on exact value, but by feel, I wanted a swing to feel natural and even for my swing; so calculated value typically get in 20.9 to 21.1 range, but these are not accurate since I didn't measure the exact swing weight). And my observations are that setups tuned this way, set at typically 352-360 grams and 340-360 SW, swing easily and fast for their specs. Few other players tested them and each of them was surprised when I told them specs as they play with much lighter setups but didn't have a hard time to hit with them.

    Whenever MgR/I value is really low, say, lower than 20.5, such a racquet usually becomes tiring to swing. Such setups usually occur when you add significant amount of lead at the upper hoop, especially at 12 o'clock, without any mass added to the top of the handle, throat, or 6 o'clock. Lead at 12 o'clock really slows a racquet down, unless a platform is designed as stock depolarized (like Tecs 315 Ltd).

    As for going over 21 or 21.1, I don't like the effect. I cannot get used to timing and if setup has a high static weight, increasing further MgR/I can make it feel lagging in a different way.
     
  47. Irvin

    Irvin G.O.A.T.

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    If you add mass to 7" you will increase SW. If you increase SW you increase the force required to swing the racket. Adding mass to a racket will make it swing faster when pivoting from a 0 cm pivot. When you're playing tennis the racket will not be easier to swing and it will not be less tiring.
     
  48. Subaruvich

    Subaruvich Rookie

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    This is really heating up
    I can say from my personal experience MgR/I really worked for me.I have seen people here saying MgR/I is BS, and others saying it does the thing. So, encouraged by @zalive I decided to try myself before making any judgments. I measure all my racquets on RDC insanely carefully before and after stringing and after any modifications. I am not saying my measurements are super precise, because that RDC is just a machine and needs calibration once in a while, but it shows the trend and direction where I'm moving with my modifications before I test the racquet on the court. Not getting into details, what MgR/I gave me was proper weight distribution. It allowed me to play with heavier and higher SW racquets with less fatigue. If before my frames were around 340g static weight and SW320 strung, then now I play with 360g+ and SW330-350. In my experiments following racquets were involved: TEC 315LTD, C10 PRO, PS2017, TC90, TC95 RA63, TC95 RA70, PT57A, iPrestige MP and other. I am not saying it will work for everyone, the MgR/I value you try to achieve depends obviously on your height, reach, fitness and game style, but it worked for me and I am happy about that.
     
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  49. Irvin

    Irvin G.O.A.T.

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    @subaruvish you are one of the lucky ones (50% in post 792) it works for. Look at it this way, once you reach your ideal ration any mass you add no longer helps. Do you think there is a point where mass added at 7" no longer speeds up the racket. I find all the rackets I like are real close to an MgR/I (ratio) of 21. But if adding mass at 7" moves you farther and farther from your ideal COM/Inertia ratio it will never work. I believe for any given mass there is an ideal ratio of Radius to Inertia that will would best for a particular player. I do not believe adding mass to 7" will allow a player to swing faster. The only way a player can swing faster is to apply a greater force, remove mass from the racket, or redistribute the mass so the COM is closer to the pivot.
     
  50. saleem

    saleem Rookie

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    I think it depends on your body type (height, arm length etc... taller guy might benefit from it more) and how you hold the racket, modern grip players will not receive as much benefit out of mass at 7" as conventional stroke players.
    It is good to have this as an other tool in your belt, try it and see if it works for your body type and your strokes if it does not work you can simply remove it, same as lower or higher tension on poly strings, just try and see if it works for your game if not go back to your "normal" tension.
     
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