Decrease Swing Weight

Discussion in 'Racquets' started by tennis.yellow.balls, Feb 15, 2010.

  1. tennis.yellow.balls

    tennis.yellow.balls New User

    Joined:
    Jul 29, 2009
    Messages:
    75
    Location:
    The Bayou
    Is there any way to decrease the swing weight of a racket to make it more maneuverable?

    I notice that some posts here says, to make the racket more headlight to make it more maneuverable, but that just means adding more weight to the handle end. I would rather find a way to make the racket maneuverable by decreasing the swing weight. Not sure if this is possible and make senses?
     
    #1
  2. ccmasterk

    ccmasterk Guest

    I don't think it's possible to reduce swingweight. Swingweight is part balance-part weight, if you lower the balance by adding tape to one end, you'll still be increasing the weight, so the swingweight will still go up.
     
    #2
  3. Jinx

    Jinx Rookie

    Joined:
    Jun 16, 2009
    Messages:
    209
    to reduce swing weight, you have to reduce the static weight. This can be achieved by cutting parts of the handle off, shaving off the bumper guard.

    it's simple physics... you can't add weight to reduce weight.
     
    #3
  4. JackB1

    JackB1 G.O.A.T.

    Joined:
    Jul 23, 2009
    Messages:
    14,128
    Location:
    Roswell GA
    there are hundreds of posts on this subject.....also many debates on whether or not adding lead to the handle can reduce "perceived swingweight". Use the "Search".
     
    #4
  5. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Methods:

    1) Shorten the frame. Most effective, removing 1/2" drops swingweight by ~ 25 units. Not as hard as it sounds, but quite a commitment.

    2) Shave or remove bumper. Bumpers weigh between 5 and 7 grams or so. Removing the entire thing can cut 20 or more units.

    3) Switch to lighter strings. I did this for quite a while with a K90 a while back. More effective than it sounds - a 16 gauge poly stringjob can weigh 20 grams or more while a 17 gauge multi can weigh 13 grams or less. That 7 gram difference represents 14 swingweight units. Of course, if you like playing with poly or gut (also heavy) this is quite a sacrifice to make for an easier swinging racquet. (I ended up switching to Asian K90 because I wanted to play with gut/poly)

    4) Add weight to the butt. Doesn't really reduce swingweight, but doesn't add to it either. What it does do is make the frame more maneuverable at the net, raises the center of percussion and makes it more stable, especially on volleys and returns (as it raises recoil weight). Worth trying (easy to reverse), especially if you like to attack.
     
    #5
  6. JackB1

    JackB1 G.O.A.T.

    Joined:
    Jul 23, 2009
    Messages:
    14,128
    Location:
    Roswell GA
    Huh? How can you add weight ANYWHERE on the racquet and have zero effect on swingweight? True, the lower down on the racquet (away from the tip) the less effect it has, but it WILL increase swingweight. It's simple physics.
     
    #6
  7. OHBH

    OHBH Semi-Pro

    Joined:
    Aug 8, 2009
    Messages:
    590
    It won't have Zero effect but if you plug in some specs using this calculator http://www.racquettech.com/store/learningcenter/lc_combinedswtbal.html
    You can add an entire once to the racket and the swingweight will only increase 2-3 units, so long as you don't go further than an inch or so up the handle.
    For example plug in this
    Starting weight: 330 grams
    Balance: 31 cm
    Starting Swingweight: 337

    If you add 28 grams at 3 cm the Swingweight goes up less than two units but the rackets becomes about 8 pts HL
     
    #7
  8. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Well, I'm not a physicist, but I'm not so sure the physics is so simple. Recall that the reference swingweight, the one listed in the specs, or the one you can calculate by swinging the racquet at home, is measured from an axis 10 cm from the base of the racquet. This is fine for comparison purposes, but it's actually more useful to calculate swingweight for axes about which the racquet actually swings, such as the wrist, elbow or shoulder.

    Using the parallel axis theorem we can do this. If I take a frame with specs of, say, 340g/32cm/320SW and add 10 grams to the butt I'll have 350g/31cm/321.9 SW. So the swingweight will have risen less than one unit at that 10cm point. But it will actually stay roughly the same if we calculate it at the wrist, elbow shoulder. Since these are the actual axes of rotation when we swing a racquet we can say the swingweight pretty much stays the same.

    That's what the numbers say, from the physics calculations, so you can argue about it all you want, but if you're talking physics - there you go.
     
    Last edited: Feb 16, 2010
    #8
  9. OHBH

    OHBH Semi-Pro

    Joined:
    Aug 8, 2009
    Messages:
    590
    Way to basically copy my post. lol.
    The calculator i provided in my above post measures at 10 cm. Is this not considered an axis of rotation? 10cm is generally where the index finger rests.
     
    #9
  10. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Ahem, ahem
     
    #10
  11. kaiser

    kaiser Semi-Pro

    Joined:
    Feb 11, 2010
    Messages:
    703
    Location:
    Holland - Belgium
    Thanks for that Corners, but could you explain why adding weight to the butt raises the centre of percussion? That could be very useful when trying to increase a racket's serve potential...
     
    #11
  12. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    ^^^ The formula for center of percussion is: COP (cm from butt) = I/(M*R)

    where

    I = Swingweight at 10cm from the butt
    M = mass in kg
    R = balance point minus 10 cm

    You can see that

    1) increasing the swingweight while minimally lengthening balance will raise the COP (in other words, lead at 12 o'clock), and...

    2) shortening the balance (making more HL) while minimally increasing mass will raise the COP (in other words, lead in the butt).

    Adding mass at 12 is three times more efficient in raising the COP than adding in the butt, but increased swingweight comes with it.
     
    #12
  13. OHBH

    OHBH Semi-Pro

    Joined:
    Aug 8, 2009
    Messages:
    590
    I'm just kidding. I managed to post hardly a minute before you.
     
    #13
  14. Don't Let It Bounce

    Don't Let It Bounce Hall of Fame

    Joined:
    Sep 15, 2009
    Messages:
    1,623
    This is interesting, and not something I had considered before. It suggests that Wilson's marketing claim that the Hammers raised the CoP was misleading: most Hammer models after the first couple of years had SW no higher than traditionally weighted racquets. For those models, the reduction in M (mass) was probably negated by the increase in R (balance point), so if there was any increase in CoP it couldn't have been much.

    I've seen it claimed on these boards that tailweighting does nothing but lower balance; that claim would appear to be refuted by the equation CoP = I/MR, as you noted.

    It also might help explain the more polarized weight distribution (high swingweight while maintaining HL balance) of pro racquets when compared to stock models. If they keep mass down (which they do, compared to pro racquets of past decades), they are really getting the CoP up near the top of the stringbed.
     
    #14
  15. defrule

    defrule Professional

    Joined:
    Jan 11, 2009
    Messages:
    826
    Always wondered, why is it 10cm?
     
    #15
  16. Bud

    Bud Bionic Poster

    Joined:
    Jul 23, 2007
    Messages:
    31,170
    Location:
    San Diego, CA
    That's approximately where the middle of your hand lies when holding the racquet.
     
    #16
  17. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Yeah, that is definitely one of the advantages of a polarized frame - high CoP. The Volkl PB10mid, for example, going by the stock specs that TW has listed, has a CoP 56.78 cm from the butt (343g/31cm/337SW), while the BLX 90 (TW specs: 354g/31.5cm/333SW) has a CoP 53.75 from the butt. The polarized Volkl's CoP is nearly 2 inches higher on the stringbed.

    Regarding the Hammers, keep in mind that tip weighting will raise the CoP three times more, gram per gram, as tailweighting... as long as the balance doesn't get too long. Were the early hammers quite head heavy? I suppose so. Anyway, compare Wilson's BLX Tour, one of the only (the only?) descendants of the Hammers still in Wilson's lineup (and with quite a high swingweight, maybe Wilson also noticed this problem):

    309g/34.6cm/341SW -> CoP: 54.86cm from the butt. Still pretty high on the stringbed. Still pretty polarized despite the lack of weight in the handle. But if we stuck 30grams at 1" from the butt the CoP would get even higher:

    339g/31.75cm/342.7 -> CoP: 56.47cm

    I think a serve and volley player could get along with the tailweighted one but would find the stock BLX Tour unstable, but then again Justine Henin is attacking pretty well with hers since her comeback (but I wonder: the press has reported that she and her coach added weight to her frame this time around. Where?).

    Also, because the center of the stringbed on a midsize is higher than on a midplus or oversize, the CoP can be a bit closer to the butt and still be in the same relative position. In other words it can be more traditionally weighted and still have a high CoP.
     
    Last edited: Feb 16, 2010
    #17
  18. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Me too, I think we were typing at the same time.
     
    #18
  19. kaiser

    kaiser Semi-Pro

    Joined:
    Feb 11, 2010
    Messages:
    703
    Location:
    Holland - Belgium
    Thanks corners, that is really very helpful, I also was under the impression that weight in the but did nothing much beyond shortening balance. I guess I had even formed a vague notion that, if anything, it would lower COP, probably from some side-remarks by xFull. Now the whole polarization thing makes a lot more sense to me!
     
    #19
  20. kaiser

    kaiser Semi-Pro

    Joined:
    Feb 11, 2010
    Messages:
    703
    Location:
    Holland - Belgium
    Corners, I'm confused. When I put these figures in your formula
    COP (cm from butt) = I/(M*R)
    I get for the Volkl
    COP = 337 / (0.343 * (31 - 10)) = 46.8
    and for the BLX 90
    COP = 333 / (0.354 * (31.5 - 10)) = 43.8

    What am I doing wrong? :confused:
     
    #20
  21. corners

    corners Legend

    Joined:
    Jul 31, 2008
    Messages:
    5,441
    Hey, sorry about that. The formula as I wrote it calculates CoP from the 10cm swingweight axis. So to get the distance from the butt simply add 10cm:)

    A more useful formula:

    CoP (cm from butt) = I/(M*R)+10

    Where

    I = swingweight at 10cm (the swingweight quoted in TW specs)
    M = mass in kg
    R = balance in cm minus 10
     
    Last edited: Feb 18, 2010
    #21
  22. kaiser

    kaiser Semi-Pro

    Joined:
    Feb 11, 2010
    Messages:
    703
    Location:
    Holland - Belgium
    Ahhh, should've seen that! Thanks.
     
    #22
  23. rst

    rst Rookie

    Joined:
    Jan 23, 2012
    Messages:
    254
    Location:
    northern nv

    the myth search specifically.
     
    #23
  24. tennis2live

    tennis2live New User

    Joined:
    May 2, 2014
    Messages:
    1
    Nice points to consider!

    Other method to consider is that.....

    Could we drill/shave each of the string holes, thus make make it a bit bigger hole then put the grommet back. This will make the head lighter, lower swing weight and improve the manueuverability?

    Have any one tried this before?
     
    #24
  25. 15Love

    15Love New User

    Joined:
    Jun 7, 2014
    Messages:
    34
    You could also remove the paint job on the racquet. Replace it with a lighter coat and it will weigh less and have a lower swingweight with most of the weight removed in the head area.
     
    #25

Share This Page