Only for those interested in string and how it affects your feel/game/control/power/t

[GeoffWilliams]

String is far more important than frame by a 75/25 ratio or thereabouts.



The best string job depends on how each person plays, the frame they use, the style they use, their own preferences. The object is to match the frequencies of string and frame so that they achieve the best pocketed feel for their game. Any sting job creates a “pocket”. This pocket determines everything we feel after impact.
The ball is only on the bed for 4-7/1000th /sec., yet, the frame wobbles with a lot of vibration when string causes it to vibrate/and move with the pressure of the outgoing shot on the string bed. This pressure is the force of impact, and that varies with player skill and player power, frame mass, RA ( ra is just stiffness or stiffness measurement of any given frame when bent with a given force and measured in terms of racquet analysis), string stiffness/elasticity/molecular distribution all differ from string to string and sometimes even within the same reel the same string varies. Talk to John Isner about how he used to snap Technifibre redcode more often in the first section of the reel than the last section of the reel! (Plays with Kirschbaum pro line II/redcode hybrid now.)

All that feel you get is from the vibration after the impact, not during the impact. That is due to the very short impact duration. The impact is too short to feel by itself. The strings stretch, sing, vibrate, and so does the frame, stretch, sing and vibrate, but for a far, far longer time than the ball stays on the bed. Blink your eyes. Now see how many times you can blink them in one second: One-thousand-One. About 3-4 times? The ball would have left the string bed about 80 times per blink! So if the ball only stays on the string bed for such a short time, why is there such a huge difference in the way the shot feels?
Every string job feels different, even with the same string, same stringing machine, same tension, same stringer. Why is that?
As the frame is taken off the stringing machine, the string immediately begins to lose tension. No two frames are exactly alike either. Some strings lose way more than others, in a way faster time. Rpm blast is one of these although it’s listed as a stiff string at 280 by RSI:

Any stringer will tell you that although rpm is listed as stiff, it feels soft when hit with, and it loses tension way too fast: RPM loses 17.37 lbs lost in 24 hrs. from a base of 62lbs strung on a 120 mph test. But, the tested and given stiffness rating does not always equate to controlled feel as a stiff string. Some strings listed as stiff don’t feel, nor play that way. And some strings listed as stiff have less control than the softer ones do. And gut is softer than almost all strings, yet has the most control when hybrid with a great poly cross. Why is that?

So if string loses tension so fast, even when not being hit with, how can any string job feel the same unless the frames are strung at the same time, with the same method? The answer is: they can’t. Although it takes a sensitive player to feel it, any frame strung first will lose tension faster and feel looser than the frame strung last, given a similar time hitting with each in the same time frame. The rates of vibration on each frame will also differ slightly as the string jobs loosen up, the frames themselves differ slightly, and their effect on the individual racquet frame will differ as well. The amount the string stretches, or elongates: will also effect what we call “trampoline”, or shots going too far long and out of the court. Here is an elongation table used by top stringers: This table shows just how much a given string will stretch, over a time with the same weight attached to each string for the same amount of time, and each string tested is struck with the same amount of force, and the stiffer strings vibrate at a higher frequency, yet, don’t necessarily lose tension slower on a linear scale than the softer lower vibrating string do, such as ashaway Kevlar 16g, which loses 27% tension over night compared to 8% for vs gut, yet, ashaway is 764 on stiffness, and vs gut is 109, which is way less vibration/frequency and is therefore way softer than ashaway kevlar. The reason why top stringers consult with it is to see which string should be strung at a lower/higher rate to match in a hybrid combination.
elongation pdf https://www.stringway-nl.com/en/TAon...sification.pdf

it does not tell the whole story to those interested in matching hybrids frequency wise.

Rate of vibration and how that affects feel/control/power/durability: Some of the vibration factors are : size or thickness of string expressed in mm, stiffness expressed in a number given by rsi ratings based on the individual string vibratory rate on test, tension, frame RA, frame size, frame lay up. Frames are hand made, and no two are exactly alike. That is why you prefer one frame over another over and over again: it vibrates more to your liking even though all the frames are supposedly identical, they never are.

How to achieve the most control in a given set up: Usually the softer strings have a lower rate of vibration, like gut, or synthetic gut. Although gut has the best tension loss numbers, synthetic gut does not hold tension well, and its rate of vibration changes rapidly compared to gut as it becomes looser faster than gut does and does not hold tension nearly as well. Tension is lost faster with harder hitters, and with those who use a more open string pattern and a stiffer frame at a higher tension strung. A string becomes looser as it loses tension and elongates/stretches out and its rate of vibration always lowers in pitch, so a set up that causes faster tension loss will need to be restrung faster. Gut loses tension less quickly than any other string although it is among the softest strings made. As syn gut stretches out, it embeds more, at impact, and more depth occurs. This does not mean more dwell time on the string bed. What difference is 1/1000th of a second going to make, anyway? This is partly why so many singles players change string jobs so often, while doubles players, who hit way fewer shots, serve only every fourth game, versus every other game, don’t spend money on string jobs, choosing to string only one frame per tournament rather than one every 8 games, as is often the case. Singles is far more competitive, more prize money, and more ego on the line than doubles so the doubles players don’t spend as much on string jobs.

No string has better hybrid control than gut, although a full gut job in today’s stiffer frames has too much trampoline and too many shots go out long because of the increased power and elongation and stiffer frames that impart more force at impact, such as the Babolats... The elongation tables will show you the tested numbers for each string type. That is why so many hybrid poly with gut, to dampen down gut’s elongation/trampoline issues. The stiffer strings in a hybrid job, whether in main or in cross, are strung at a slightly lower tension, to match vibratory rates with the lower vibrating, softer string. The higher rate of stiffness, the higher frequency of vibration with both frames and string and string tension as well….. So the poly is really there just to bring up the gut’s vibratory rate and dampen down its trampoline issues. Lower vibratory rates of any hybrid string job applies more force to the ball at impact, as the lower rate will allow the ball to sink further into the string bed before recoiling outwards. A great poly/poly hybrid for control is l-tec os premium 16g/4s 17g squoval shaped string as cross, and tour bite 18g/l-tec 4s. The l-tec 4s is a good cross for many different mains due to its pocketing effect.

[GeoffWilliams]

RA equates to frame stiffness, or racquet analysis.



The effect of RA frame stiffness on control is also important. The term RA goes back to the early RA Test Machine, (Racquet Analysis) so those numbers that were initially achieved, (flex and SBD [string-bed-deflection]) simply became a frames’ RA Value. It became the benchmark used in the industry to measure basic stiffness when applying a specific force used to bend the frame (weight) to a frame where the opposing force (a steel bar) is placed at 32.7cm from the head/top of a racquet and the stiffness rate of the frame is measured when bent with this weight... The Babolat rdc (racquet diagnosis calibration ) machines are the bench mark RA testers. The original RA Test System was developed by: Weidmann + Weber - a SWI group - sold to Babolat who distributed the device . And there were many copies. The Gamma copy sucked. The stiffer frames, vibrate at a higher Herzog rate when impacted with the ball, and don’t bend as much, than the flexier frames, but not by much in the lab. The rdc (racquet diagnosis) machine tests this by bending the frames against a center bar. It’s on the court that we feel the huge difference between a 60 RA and a 70 RA in our hands and arms and how the ball reacts, and it is hugely different. Video on how the rdc mahine is used. http://www.youtube.com/watch?v=67ndPgE5ITU The lower rate of vibration in a frame, imparts less force to the string bed, and the depth of shot is less because of it, so we feel more in control with less power/trampoline. But string is different. Lower vibratory rates of string often cause more depth, not less depth, and the opposite is true in frames. It goes without saying that the stiffer frames, stiffer strings, higher tension, all will hurt your arm/elbow/shoulder more. The 18 x 20 closed patterns also provide a smaller squared pattern, more friction on mains/crosses, so there is less snap back, less trampoline, and a perceived more controlled effect due to the smaller space in-between the strings causing more friction, and less string movement during impacts and less string wear.
Some say that spin is control, which would mean that a more open pattern, strung looser, with a spin string would provide the most control, but that is not necessarily true, and a matter of whether or not your own style is a spin style, or a flat hitting style, an all court style, or a grinder style, an attacking aggressive style, or a push-lull style is best suited to the frame/string hybrid you are using. Only you can say what your own strengths and weaknesses and tendencies are in a match situation, and only you can say which string job feels the best to max out your strengths and minimize your weaknesses, so it takes a lot of introspection to attain those insights.
So you have to find out exactly what they are: weaknesses and strengths during practice and match play sometimes differ. So everyone: Play like you practice and practice like you play. So a flexy frame, 18 x 20, 98 sq. in type set up strung at a higher tension, with a soft main/stiff cross, is not necessarily the best pocketed feel for your own game, unless you are a flat hitter all court type. (Djokovic.) A baseline grinder will usually want a more open 16 x 19 100 sq. in. type pattern, more heady heavy, a rounder grip pallet shape, a stiffer frame, an edged spin string, strung a little lower for the best rpm effects. (Nadal.)

Silicone spray is used by many some players to increase spin: Here is a study showing the spray increases spin by 14% and slow motion shot of snap back: So is wax, and crayons on the intersections only.



Many equate control with stiffness, due to the stiffer strings ability to impart less depth on the shot. As the string vibrates in a higher/shorter duration frequency mode, the impact transferred to the ball is lessened for a shorter/faster amount of time. Hence, the misunderstood nature of “control=stiffness”, which is really affected by many factors other than pure vibratory stiffness. There is also the individual tests done on similar frames, and how long those string jobs have sat, on the bench before testing, losing tension. We don’t really know those figures. Once again, stiffness is the really the measurement of vibratory rate of the string, a test by a machine that strikes a ball with the frame, string job set at 62lbs, at the equivalent speed of 120mph per strike, and averaged over several shots per string job. That’s rsi’s method of determining stiffness rates of strings: vibratory rates. The higher vibratory rate of a frame, the more powerful it is and the more hard it is on you. The higher vibratory rate of a string can vary depending on the molecular make up of that string, it’s true elongation rate, and its true elasticity rate and they are not the same thing, and that is why stiffness does not equate to feel or control. These will also vary with string thickness, weight of the frame, power of individual players, age of the string job, and time on court hitting with it. Is it any wonder how hard it is to get a great string job?

The poly used as cross also has a “smoother” surface than animal gut has, and many polys are infused with Teflon such as alu power to make sure the mains are able to slide and “grab” the ball upon snap back. It’s not really snap back that grabs the ball. It’s snap down/up. The mains slide downwards as the ball strikes them if top spin is used, and if slice is used the mains slide up. In both cases the mains snap back to original position shortly after impact if the cross string and mains are low friction. If the strings are high friction, there is less “grab” on the ball, but if the strings are very slippery, there is also less grab. Grab is a very tricky thing to master, and changes for a given string/frame/tension set up. String jobs are in a constant state of degradation. It can be very sensitive to achieve the right combination as string grab rates affects spin rates and depth rates to match an individual’s game. Is it any wonder why top singles players switch string jobs and frames every 8 games? The deadly nature of modern competition demands it.

Thickness of string and how it affects control: Once again we arrive at vibratory rate. The same type of string in a thinner size, such as 17 versus 16 gauge, will always vibrate at a higher rate in the thinner gauge, just like a guitar string will. So the same tension, same frame, stringer, and the thinner string will ping out at a higher pitch sonically. There is less mass to the thinner string, and less matter to transfer the same amount of force, same amount of tension, so the vibratory rate is higher to compensate/transfer the force struck into it. Consequently, the thinner string as it imparts higher frequencies, moves more, has less friction due to less matter in the way of tensioned string: the string sticks up less in profile. A string that moves more imparts more spin and lasts for a shorter amount of time, saws more quickly, and has more friction wear as it glides back and forth more and is less thick. So thin strings never last as long, have more power due to more elongation, and more spin, and lose tension faster due to all these factors, causing more trampoline to occur at a faster rate than the same string’s thicker counter part. That is why many people prefer one string over another in a very slightly different gauge: they either prefer the increased spin, or power, or durability, or the vibratory rates appeal to them in how the given string pockets in their given frame and suits their given style more, even though very slight differences in string thickness are felt to be so huge when ball strikes the string bed...

[GeoffWilliams]

It's all about pocketed feel in match play, and also for enjoyment.

How to achieve the best pocketed feel: Strings with a high coefficient of friction are slippery, such as l-tec 4s or alu power. The 4s has a cof of 6.7, and makes a very good cross if you are looking to increase pocketed feel. See the tw professor: http://twu.tennis-warehouse.com/lear...ringfinder.php These strings make the best crosses in a hybrid job because they don’t get in the way as much. Such as Kirschbaum spiky shark, Solinco revolution, tour bite 18g, Dunlop black widow, Signum pro tornado, Volkl cyclone 18g, Kirschbaum pro line II. They allow the mains to impart most of their characteristics without negatively affecting the grab of the mains. But I found that if you spray silicone on the strings, all the strings, including the mains, are affected, not just Teflon infused crosses and grab disappears and snap back feel is lost as the ball just slips off the string bed without much feel at all. Crosses with more friction stop the mains from sliding much, as do higher tensions, tighter patterns, thicker crosses. Thinner strings will also allow more gliding compared to the thicker counter parts. Crosses are the tensioners, and I have often restrung vs team gut hybrids, when vs is main, before crosses broke, locking down frame, and re-pinging out the mains to test for even tone and tension remaining. (You have to know what you are doing or the frame will crack prematurely.) No string holds as main as well as vs team gut, and it’s the Ferrari of gut for that reason. Vs team is the string used by the top pros. (Fed uses it packaged by Vs at the same factory in a Wilson package.) It’s not just the frames that are paint jobbed! No string has better pocketed feel/control/touch/power when coupled with a top cross like l-tec 4s or alu power. It’s the crosses that determine the pocketed feel of the mains. Not the other way around.

Changing cross tensions versus the main tension. What the pros do and why.

Many stringers also change tensions on crosses versus mains to match vibratory rates so the pocket feels more natural. Top stringers will drop the tension on the stiffer strings in hybrid, even if those stiffer strings are used as mains such as Murray does in his alu/vs team hybrid. Nadal can get away with rpm 15 gauge 1.35mm (only he can obtain it) in his apd original frame (does not use cortex) at 54/52lbs because his fame weighs only 341g. (5” lead strips under the grommets at 12 oclock, 1/8” or 33mm wide. Federer can get away with his 48.5/46.2lbs vs team/alu rough at such low tension because his frame is only 90 square inches. Djoker can get away with his 60/58lbs vs team/alu hybrid at 359g because he has a 98 sq. in. frame custom made and customized with lead and silicone in the handle. Djoker has the best set up for power/control with a 359g mass, soft 54 RA, vs team gut/alu power, and Nadal has the best set up for spin/control with a 16 x 19 66 stiff RA (apd original) and lead at 12, polarizing his frame weight and balance. The use of lead and silicone are there for dual reasons: to dampen down the impact of in/outgoing shots and to shape the mass and pocket and balance of the frame and to add mass and power to the heavy ball shots.

Silicone softens and dampens the feel like a shock absorber, and the clear soft type is injected into the hande, about 25g of it, with light weight material to stop the silicone from going down the frame, and the frame is set up right to cure/dry the silicone for several days before use. Lead is used to affect the pocket, move it up or down in the string bed, and also change the balance point or twist weight or swing weight to match a player’s preference. Volleyers often prefer a non polarized set up: lead at 3 and 9, like Sampras used, and while baseline grinders often prefer a more rounded grip handle shape, a more polarized set up, with lead at 12 like Nadal uses, and Fed uses lead in-between 3-12-9 all the way around. Djoker uses lead all the way around the hoop down to an inch below the last cross. His frame is the most flexy of the top three, at a tested 54 RA by Raven compared to 65-66 RA for Fed and Nadal.

Top stringers will also change crosses to improve pocketed feel. They will either increase the first few crosses in tension or lower it, depending on client preference. When the first three top crosses are increased in tension by a few lbs each, such as: going down from the top: 65-63-61-58, that affects pocketed feel quite a bit and will increase frequency ranges and act to combat tension loss. This coupled with a top cross like l-tec 4s increases pocketed feel immensely for sensitive players. Reversing the pattern also is a preferred feel for many players. Such as 45lb firs three down, 65lbs next 8 down, and 55lbs for the remaining crosses.

Lower the same crosses in tension, such as: going down from the top: 32lbs-32-32-32-32-32-40 like Davydenko does, it increases felt pocket power and trampoline and decreases frequency ranges, rather than shaping it downwards, it shapes it upwards and loosens the string bed, increasing trampoline and power. He uses poly star energy, a top power string. Changing the bottom few crosses will also affect feel. Raising these, such as bottom last crosses going down: going down near the bottom of the frame: 58- 63-66-70 acts to crispen the feel, and combat tension loss, not loosen it, like the Davydenko method. Trends toward these more powerful lower tensions are occurring in the pros such as Raonic: 42/44 or 45/47 at IW (altitude requires higher tensions due to less molecules in the air to keep the ball in play) for several reasons: Lower tensions create more power/depth/spin and are easier on the arm. But they are harder to control in the longer rallies, so they are more appropriate for power finishers like Raonic than grinders like Nadal or Ferrer.

Many stringers will also vary the tensions on the mains, such as in an 18 x 20, the first 8 mains are done to a lower tension: 58lbs, than the next two: 60lbs, and the last two on the outsides: 65-70lbs, to create a job more resistant to tension loss, and shape the pocket more towards the center, longer mains, which ping out lower in tension due to their longer measurement and lower pitches anyway. With a 16 x 19, it’s the first six mains. Many stringers also ping out the mains before installing crosses, to make sure each corresponding main has the same tension and sonic ping, so that when the frame is flipped over, it will feel the same and will stop tension creep across the bed. Tension creep also acts to move the pocket. As the string loosens, the pocket moves downwards and out of range of most hitters. Many top pros hit up in between the 4th and 6th crosses down from top because that’s where the most leverage is. Changing tensions on mains is done by shoving down on them with a thumb and pushing the tension towards the balance point. Then you ping them out again to match. Like tuning a guitar. Many stringers also string poly no higher than 54lbs due to its loss of pocketed feel above that range.

Many stringers vary the tension by a few pounds lower/higher in a given range to give the player the best chance for the pocketed feel in any given arena. They will also measure balance points frame to frame, and make sure the balance points are the same by varying the amount of lead placed under the frame grommet strips, 1/8” or 33mm lead tape. Here are Feds frames. Notice the lead changes? Frames will require serveral different inches of lead frame to frame to maintain balance and swing weights. What is a balance point and what is a swing weight? A balance point is how far out from the handle butt edge, does the racquet begin to tip over the balanced edge, such as 33 cm. A swing weight is the measurement of a frame’s inertia when swung, which is the amount of force it takes to overcome inertia. The more weight out towards the end, means a heavier swing weight. Swing weight describes how heavy a racquet feels when it is swung and can affect maneuverability at net and heavy balls from the baseline. Swing weight increases as the racquet's weight is distributed more toward the head, so head-heavy and extra-long racquets have a high swing weight in relation to their stationary weight. A high swing weight results in low maneuverability, but generally more groundstroke power. Twist weight is also used to describe how heavy the sides are of a frame, and how much it resists twisting. Weight at 3 and 9 is generally used to control twist weight and to stabilize twisting forces.

[GeoffWilliams]

Swing weight and twist weight have a large affect on your game.


How to measure swing weight:
Swinging and impacting a ball torques a racquet in three ways and each torque rotates a racquet around a different axis. The resistance to rotation around any axis is the “swing weight” around that axis. Swing weight around the handle is simply called swing weight. This measures the distribution of weight along the length of the racquet, which in turn determines maneuverability, and stability along that axis when you swing the racquet
Twist Weight (Off-center stability): Swing weight around an axis drawn from butt of the racquet to the head. This measures weight distribution from side to side and its effect on maneuverability and stability to twisting by you or the ball. The higher the value the more stable when you hit a ball above or below the center axis of the racquet. Values are expressed in kg•cm2 and range from 13 to 21. The majority of racquets fall between 13 and 17. Values given for strung racquet. A higher twist rate means less energy of impact goes into pushing the racquet backwards or twisting. The result is more comfort and power.
Recoil Weight (Shock resistance): Swing weight around an axis parallel to the racquet face and through the balance point (center of mass). This measures weight distribution from the head of the racquet to the butt and its resulting resistance to recoil. Values are expressed in kg•cm2. Value given is for strung racquet. The higher the value the less shock you feel. A higher recoil rate means less energy of impact goes into pushing the racquet backwards or twisting. The result is more comfort and power.
Hitting Weight (Effective Mass): Although not actually one of the swing weights, Hitting Weight is important because it shows the amount of the racquet’s mass actually involved at the impact at any given location along the string bed. If the ball hits the racquet at the balance point (center of gravity) the racquet behaves as its full mass. Anywhere else, it behaves as if the racquet were lighter than its actual mass. At the tip, the hitting weight is approximately 25% of the racquet’s total weight. At the center of strings, it is about half. The hitting mass is important because the power of the racquet at any given impact point depends on the hitting mass at that point. More mass means more power. The impact point is usually determined by the wear pattern of the strings. The hitting weight is also leveraged by the length of the contact point from the handle butt. Many top players hit in-between the 4th-6th crosses down, not in the center.
• Hitting Weight is presented in two forms; one is the calculated total mass in grams/oz. The other is percentage of total mass/weight being used based upon the leveraged impact in the string bed where you are actually hitting the ball, based on your wear patterns on the string bed.

Players often talk of “dead” poly, string that has lost its elasticity, and is beginning to hurt their arm/elbow/shoulder. Players often talk about “trampoline”, as the string gets too stretched out, and loose, the balls go long. Players with heavier frames have to string higher to balance out increased mass caused trampoline, and that is why many top pros string 60-63lbs still and almost all drop the crosses down a few pounds for more glide/snap back and power as the crosses are the tensioners. They play with frames that weigh : 365g: Federer: 359g: Djoker: 355g Tsonga etc. Nadal is the light weight at 341g. Many stringers will also double pull and use flying clamps to make sure tension pulls are not suffering from tension loss, and to achieve a more exact feel. Although string can differ reel to reel and set to set, and frames can differ frame to frame as they are handmade, the quality of your sting job can be constant, if not the tension loss. Any string, even vs team, will lose tension on you especially if you use a heavy frame and hit hard with a lot of spin. Open patterns like 16 x 19 will burn through string 3 x faster than 18 x 20 patterns especially for hard hitters. Many will also double pull crosses, and wait about 10 seconds before pulling between each pull, to allow string to form its settled base without violent fast pulling during stringing. Many also pull poly at a slower rate of pull to lessen tension loss/elasticity loss. All of these methods are intended to increase pocketed feel as per individual preference as some poly is very sensitive to stringing methods and tension used.

Many stringers also tighten the last strings to counter balance knot tension loss, which often accounts for as much as 10lbs more on that last string. Many stringers use a bulky knot to start with to make sure the knot does not pull through the grommet hole on the first cross, and most use Parnell or Wilson pro knots elsewhere. http://www.youtube.com/watch?feature...&v=BUFjDax7xK4 wilson pro knot
http://www.youtube.com/watch?v=mGQW_ONBPPo parnell knot
http://www.youtube.com/watch?v=UT1cXy-6Wz0 bulky knot
http://www.youtube.com/watch?v=aGyDh4gW8DE common knots

How to achieve the most power: Vs Babolat Gut has the most power. Powerful polys: poly star energy, polyfibre poly- hightec. Lower tensions on mains and the top three- five crosses down will provide the most power. You still must ping out mains, and cinch down knots to account for an exact job. Stiffer frames will give the most power, such as the Babolats. Higher RA figures will give more power, due to more pop induced to the string from the frame. Lead customizations will provide more mass, as will silicone in the butt handle, and any added mass may increase power. That is why frames come so light, so you can customize upwards. No one can chop off weight without losing leverage. Most people just hit with the light frames without realizing that few pros do.

How to achieve the most spin: Shaped and edged strings do provide more spin, such as big hitter black 7 by tourna, or blue gear ultra by Pro supex, but the blue gear ultra is stiffer so it will hurt your arm if strung too tight. Stiffer tensions, in the higher range will appear to produce more spin, but they will drop the ball shorter off a higher angle of trajectory. Lower tensions can also appear to produce more spin under about 48lbs or so. Lower tension allows more snap back grabbing if the string snaps back in time to grab the string according to the style used by the player, the speed of shot/angle of technique on the string bed, or it can cause the ball to go out more often if not in synch. Thinner strings produce more spin, hence, the love of tour bite 18 g by so many junior players. Big hitter blue rough also provides a lot of spin, as does spiky shark, Volkl cyclone 18g, ashaway Kevlar 18g, blue gear ultra twisted, ytex quadro twist, big hitter black 7, Dunlop black widow, and strings with higher friction coefficients allow more gliding of the mains to grab the ball. (Higher figures are less friction.)
How to achieve the most durability:

Ashaway Kevlar/l-tec 4s is the best hybrid for durability, at 16g thicker size. For the bullet proof arms only. I u sed to hit with it for years, strung at 73lbs. Not recommended for normals.