Choosing the right equipment:frame/strings/tension is paramount to your game.

[GeoffWilliams]

Choose well and play well. Decide if you are: a grinder: a hacker: a power player: an all courter: a spin player: a high rpm hitter: a heavy ball hitter: a light weight hitter.


High frame ra=power/stiffness more shots go long
Low ra=control/low power, less shots go long
Closed pattern=Less spin, more directional control if strung for it and more accurate volleys
Open pattern=More spin, heavier game not so great at net
Poly string=anything you want if you string/choose for it
Gut=soft/control/power/or spin if strung for it
Multis=mushy feel/less power/less depth
Syn gut=no durability, more power, more tension loss
Lead tape=heavier shots, faster serves, more shots out long and can mean less impact on arm if combined with soft silicone in handle
Silicone in handle=if soft, less impact pain and more frame mass
String hybrids: gut/blackcode or alu or l-tec4s
Spin hybrid: bhb7/poly star energy: edged strings hybrid with round power polys make the best combos.
Control hybrid: l-te os/4s, gut/alu or gut/high grade med. power poly like blackcode, medium or higher tension
TEnsions: higher means fewer shots out long and more arm risk and fewer ue, less power, lower means more power, more trampoline, more shots out long and more ue.

hackers usually like lower tensions, larger frames,
Serve/volley like closed patterns, sharper grip edges, higher tensions, heavier frames
Grinders like open patterns, spin strings, edged strings, medium tensions, rounder grip pallets
Power hitters like higher ra, stiffer frames, power strings, medium tensions sharper grip pallets

Control vs. power all courters like a medium and can vary all over the map. Usually a volleyers frame with a closed pattern, higher tensions, power strings, higher ra.

Increase the size of your string pocket: Ping out the middle first six strings in a 16 x 19 and eight strings in an 18 x 20, so that they sound the same, with the same frequency. As the strings shorten up, they ping out higher tone sonically. Then on the outer strings, increase the tension to combat tension loss and keep the pocket in the middle as tension there decreases, tension on outer higher strings migrates towards middle strings. On crosses, first three higher tension, then in pocket area, lower it a bit, and then on lower crosses, increase it a bit, but experiment for your best combo/range.

Lead application: lots of choices; 3 and 9 for non polarized set up that volleyers like, or 12 for polarized that topspin grinders like, or all around the frame, that all courters like. Must be combined with soft silicone in handle: 20-25g to deaden/soften higher impact frequencies due to higher total mass of frame. Borg played at 410g. Edberg at 405g. Becker at 400g. Sampras at 389g. Now it's more mid range: Djokovic at 359g. Fed at 365g. Tsonga at 355g. Delpo at 361g. Berdych at 361g. The light wt. is Nadal, with a junior set up: 1/4" grip, at 341g. Murray ranged from 364g-346g. 1/4" lead tape holds best, or 33mm. many pay to put it under the frame, like Djokovic does: joker frame lead tape under grommets

Best way to find the best string hybrid and tension/frame for your game: experiment a little. Many lower speed hitters like super low tensions like 40lbs. Many spin hitters like the open patterns that allow more snap back: but those strng jobs last about 1/3 as long as closed patterns due to more sawing back/forth friction, but the ball is brushed more, and strings grab more. Higher ra frames mean the ball does not stay on the bed as long, and the angle of trajectory is lower for shorter more powerful shots. Angle of trajectory is also affected by string tension: lower means higher shots and more depth. HIgher means lower shots and less depth. It's also affected by ra: and frame mass: more mass means deeper shots: less means shorter shots. So a heavy frame with a high ra would need higher tensions to keep the ball in. A lighter frame with a low ra would need lower tensions to keep the ball deep.

Best spin combo: open pattern, edged string, high ra, 12 oclock lead, light frame. Rounded pallet. Small grip for more access to flip over. Lower tension. Sound familiar: Nadal's set up.

Best power set up: gut/alu, closed pattern, mid range or higher ra, sharper pallet, higher tension, heavier frame, larger grip, sharper edges: Sound familiar: Djokovic and Feds set up. Fed uses 4 3/8 with a single over grip, while Djokovic uses L3 with two over grips, making it larger. 359g and 365g are heavy enough for heavy balls, light enough to react on serve returns against heavy ball hitters.
Best control set up:
Murray has compromised for a control set up: flexy low ra, alu full, 61 lbs, low -mid range weight, pt57a with 16 x 19 with L3 single over grip.

So what does that tell you about your game: What are the best combos for you to stop making ues? The answer is obvious. Decide what type of hitter you are and then buy accordingly. Or do what I did and waste a lot of time and money to decide which set up is best for you.

joker side by side with stock frame

joker grommets side by side with stock frame

joker throat side by side

[julian1]

Head

does Head have a racket which satisfies two conditions:
weight between 300-320 grams
TWISTWEIGHT betwen 13.5 and 14 kg*cm^2

[GeoffWilliams]

Very good question. Does anybody else find Julian is one of the most astute members here?

The twistweight of a frame scales fairly well with the mass of the racquet multiplied by the square of the head diameter. So just take any frames total mass, strung, gripped, impact absorber, measure the mass with a digital scale, to the gram, and then multiply by the frames' diameter squared and that will equate. Twist wt. although crucial to how the frame performs, is not readily available.

Player sensitivity to twistweight
In a study of college varsity players, it was found that they could distinguish two racquets apart if the twistweights differed by more than 5 percent. In a related study, the same players required a difference in swingweight of at least 2.5 percent to distinguish two otherwise identical racquets (same balance, total weight and twistweight) from each another. Adding 5 grams to the racquet head at the 3 and the 9 o’clock locations increases the twistweight by about 10 percent, so a good player should be able to distinguish it from an unaltered frame. A pro is far more sensitive, often able to tell a single gram difference, like Borg did with his 10g frames, that gained 4 g of water wt. (Expert came and placed the frames on top of borg's radiator water heater to dry them out back to 410g.
Borg then played bongo drums over them after placing them on the floor! Sonic healing of frames.

Home » RSI magazine » Science » A New Twist on the Twistweight of a Tennis Racquet
A New Twist on the Twistweight of a Tennis Racquet
By Howard Brody
One of the most important parameters of a tennis racquet, the “twistweight,” is rarely reported on. It is relatively easy to determine a racquet’s weight (all it takes is a scale) or a racquet’s balance point (a knife-edge and a ruler are needed). The swingweight of a racquet can be determined if you have a racquet diagnostic device, which is commercially available, but somewhat expensive. To the best of my knowledge, there is no commercially available instrument to determine twistweight, yet it is an important parameter that greatly affects how a racquet plays.
What is twistweight?
The twistweight (also known as the polar or roll moment of inertia) is a measure of the stability of the racquet to resist twisting around the racquet’s long axis. If you hit a ball dead smack in the center of the head, the racquet will recoil, but not twist around its long axis. If you hit a ball and inch or so away from the axis toward the 3 o’clock or 9 o’clock side of the strung area, in addition to recoiling, the racquet will twist around its long axis. The bigger the racquet’s twistweight, the less the racquet will twist when the ball impacts off-axis. In other words, it will be more stable against miss-hits.
In addition, because energy goes into a racquet’s spinning motion when there is an off-axis impact, the ball will rebound with less speed. The power you get out of a racquet degrades the further your impact is from the axis, but not as badly when the racquet has a large twistweight.
Because twistweight is a measure of the racquet’s stability against twisting and its uniformity of power, you might assume the bigger the twistweight, the better the racquet. This is not always the case. As the racquet’s twistweight increases, the racquet’s maneuverability decreases, so you must balance one against the other. Do you want a more stable racquet that has a more uniform response across its face or do you want maneuverability? A top-flight player with excellent eye-hand coordination, who rarely hits the ball off axis, will choose maneuverability. The recreational player, who tends to hit the ball over a larger area of the head, should go for stability and uniformity of response.
What determines the twistweight of a racquet?
The technical definition of twistweight is the sum of the square of the distance of every bit of mass in a racquet from the long axis. This definition does not directly help a player, because that sum is an impossible calculation. The wider the racquet’s head, the greater is the twistweight. Because twistweight goes as the square of the distance the mass is from the axis, if a racquet is 25 percent wider (10 inches versus 8 inches) it will have a 50 percent greater twistweight. Adding lead tape at 3 and 9 o’clock will increase the twistweight, but adding tape only at 12 and 6 o’clock will not increase the twistweight.
Measuring the twistweight of a racquet
In the laboratory, twistweight can be measured using a calibrated torsion pendulum. Because players and tennis technicians do not usually have a torsion pendulum handy, this is not a good solution for the average person.
There is a theorem in physics that says the twistweight (or polar moment) is the numerical difference between the swingweight (or moments of inertia) measured around the other two axes of the racquet. This is fine, if you can measure swingweight to an accuracy of a fraction of a percent. Because this accuracy is not readily achievable, this is also not a good method for determining twistweight.
There are several other possible solutions to the problem. The racquet manufacturer could list the twistweight of their racquet or the USRSA, which publishes the specifications of most racquets available on the market, could list twistweight in their annual Racquet Selection Map.
Another solution is that the twistweight of a racquet can be measured by using the procedure given on page 48 of the book The Physics and Technology of Tennis and using the following equation:

The method is shown on the USRSA on-line twistweight calculator, and it is relatively straightforward. You simply tap the racquet to set it in a pendulum motion, time how long it takes to make 10 swings, and you plug your numbers into the formula. A problem arises if the balance point is outside of the strung area of the head, which is true in many cases. Then the procedure is more complicated as shown in Figure 3 and described in the book of page 49. To get around this difficulty, you can shift the balance point well up into the strung area by adding weight to the tip and then use the method shown in Figures 1 and 2. Weight added at 12 o’clock will NOT change the twistweight, because it is on the axis of the racquet (it will greatly change the swingweight and balance, so remember to take the weights off after the measurement). To test this method, the twistweight of a racquet was measured with no extra weight on the tip, 50 grams added and then 100 grams added. The twistweight came out the same in each case, as long as the total mass (racquet plus addition) is used in equation at left.

Figure 1

Figure 2

Figure 3
There is, however, a simpler solution to the problem. Because it is only the relative value of the twistweight from one racquet to another that is of importance, not the actual value of the twistweight that is needed. The twistweight of a frame scales fairly well with the mass of the racquet multiplied by the square of the head diameter. This is fully explained in The Physics and Technology of Tennis and is presented here in Figure 4. A player can easily compare the relative twistweight of any two frames by just taking m (mass of the frame) and multiplying it by D² (the head diameter, D, squared). If all you want to do is compare two frames, it does not matter what units you use for m and D, (grams, ounces, inches, or centimeters) as long as you use the same units for both racquets. [USRSA’s on-line Twistweight Estimator makes this method even easier.] This method will not work well if the manufacturer has added extra weight at the side of the head as Wilson did in its PWS racquets or as Prince presently does in its Triple Threat frames.

Figure 4
In general, the value of the mass times the square of the diameter is about 16 to 18 times the measured twistweight. This means that using the mD² formula and dividing by 17 will usually get you within 10 percent of the correct twistweight value. For racquets such as the Prince Triple Threat series, the value is about 14.5, which means that those frames are somewhat more stable than a frame of comparable weight and size that does not have the extra mass added in the head.
Player sensitivity to twistweight
In a study of college varsity players, it was found that they could distinguish two racquets apart if the twistweights differed by more than 5 percent. In a related study, the same players required a difference in swingweight of at least 2.5 percent to distinguish two otherwise identical racquets (same balance, total weight and twistweight) from each another. Adding 5 grams to the racquet head at the 3 and the 9 o’clock locations increases the twistweight by about 10 percent, so a good player should be able to distinguish it from an unaltered frame.
From the February 2005 issue

[julian1]

Head racket again

Say that one has

http://www.tennis-warehouse.com/head_youtek_radical_midplus/descpagerchead-hytrmp.html

Say that one is NOT happy with the TWISTWEIGHT for the racket above
(head_youtek_radical_midplus)
A quarter of an ounce is added at 3 pm AND
a quarter of an once is added at 9 pm
Do you expect ANY PROBLEMS?

[GeoffWilliams]

That is a 324g swing wt., 18 x 20, 98 sq in., power level is low. (It's low due to a low swing weight/twist weight, for most hackers.) I'd add some silicone in the handle also, and the lead will be no problem, and string it with a power set up: vs team/blackcode or vs/alu, or vs/l-tec 4s, or for spin: bhb7/poly star energy, or all poly: os/4s, at a medium tension at first to see if you keep it in, like 55lb/53lbs. If you can, add more lead. If you can't, raise the tension. And so on. Rock it in.