String info

Some players know exactly what they require in terms of strings, tension, hybrid patterns, knots etc. 

Others are happy to take advice and try new strings and tensions. 

Please ask if you are unsure about the options available. 

String patterns?

The most common string patterns (mains x crosses) are 16x19 for tennis, 22x22 for badminton and 14x18 for squash. Most tennis and squash rackets do not have shared grommets for the main and cross strings. Most badminton rackets have from 6 to 16 shared grommets. The string pattern of your racket can influence the type of string and the tension that will be best suited to your style and level of play. 

String tension? 

Normally in the range of 45-65 lbs for tennis, 20-30 lbs for squash, 18-30 lbs for badminton, 28-34 lbs for racketball.   

With all else being equal, lower tension = more power, less control. Higher tension = more control, less power. 

String gauge (thickness) ? 

Badminton: 0.60-0.90 mm / Squash: 1.05-1.30 mm / Racketball: 1.10-1.45 mm / Tennis : 1.10-1.35 mm

With all else being equal thinner strings give more power and feel but will not last as long as thicker strings. 

1 string or 2 strings?  = 2 knots or 4 knots?

Some players prefer the main and cross strings to be strung separately.  Some racket manufacturers recommend 2 piece stringing due to the frame design. If you want different strings in the mains and crosses (hybrid stringing) then you will obviously need 2 strings. 

Hybrid stringing? - mainly applies to tennis / racketball

You can have different types of string for the main and cross strings which can enhance the playing characteristics - feel / power / spin. Most hybrids have the stiffer strings such as polyester as the mains and the softer strings as the crosses. 

Hybrid tensions? - mainly applies to tennis / racketball

You can have different tensions in the main and cross strings which can enhance the playing characteristics - feel / power / spin.

Injuries: if you suffer from wrist / elbow / shoulder problems, certain strings can be more forgiving on the arm. Lower tensions can also help.  

The following information has been gathered from various sources. 

String Composition

The material used in string can significantly affect a player's performance. Many types of  material are used to make strings. They vary in terms of elasticity, durability, rebound  efficiency, tension holding capability, and manufacturing cost, among other considerations.

Synthetic gut

Synthetic gut is nylon, nearly always composed of a single filament. Small changes from pure  nylon are usually found in strings sold as "synthetic gut". Textured coatings, colorants and  the addition of a small amount of Kevlar are the most common changes. Synthetic gut, as it  is used for mono-filament nylon strings, is now a misnomer, as the creation of multi- filament strings has provided players with a better approximation of natural gut's  performance. Modern "synthetic gut" is actually a multi-filament string that holds its  tension extremely well and which has a dynamic stiffness profile that is closest to natural  gut, although the industry continues to apply the term to mono-filament nylon strings.

Multi-filament, or "multi"

Multi-filament strings, known commonly as "multis" are strings that have more than one  filament. They are most commonly made of many filaments of nylon, but can incorporate other  materials such as polyurethane, Zyex, Vectran, Kevlar, and other materials. Multi-filament  strings offer better elasticity than single filament strings, but usually inferior  durability. No multi-filament string holds its tension as well as natural gut, and none of  them is as soft. However, in comparison to mono-filament "synthetic gut", multi-filament  strings can offer a much closer approximation of natural gut's performance. The softest  multi-filament strings can be made with Zyex and polyolefin, although some of the softest of  these strings are no longer on the market.

Nylon

Nylon is the most popular string material for amateur players due to its low cost and the  improvement in elasticity offered by multi-filament strings. Wear-resistant coatings for  nylon strings are common, especially with multi-filament strings, because the outer  filaments tend to break first as the racquet is used.

Polyester

Polyester is a stiff and durable string material, originally intended for use by frequent  string breakers. It took the string time to become popular, primarily due to its poor  tension holding capability. However, players feel they are able to apply more topspin to  balls while maintaining control with polyester strings. Polyester's support for heavy  topspin in particular has made it the most popular material in the pro tour. The increased  topspin due to polyester strings has been verified with controlled experiments today. The  exact cause for the increased spin is not known but there is strong evidence that the low  friction between strings is a factor.

Kevlar

Kevlar is the stiffest, most durable synthetic string available, and is thus extremely hard  to break. Although it is one of the best strings in terms of tension holding capability  (next to natural gut), it is the most dangerous string when it comes to developing tennis  elbow. Kevlar is often strung with another string, such as nylon, in order to combine both  strings' qualities, as Kevlar by itself feels too stiff for many tennis players, especially  when combined with a stiff racquet. Some advocate using a very thin gauge Kevlar for  increasing comfort, but even in the thinnest gauge it is a stiff string. Another strategy to  increase comfort and improve rebound efficiency is to string Kevlar at a low tension.

Vectran

Vectran is the penultimate string in terms of stiffness and durability. It is perhaps the  least commonly used contemporary string material. It is usually added to nylon string to  increase nylon's durability and stiffness, as with Kevlar. Yonex, for instance, offers two  badminton strings, made primarily from nylon, which have Vectran strands. However, the  Ashaway company offers a braided Vectran tennis string.

Zyex

Zyex string offers more rebound efficiency, i.e. gut-like dynamic stiffness, than other  synthetic strings, particularly when strung at low tensions. This gives it playability that  is more similar to natural gut than, arguably, other synthetic materials. It also has low  overall stiffness. The ProKennex IQ Element Z string, for instance, has the lowest stiffness  of any synthetic string yet tested. The drawback of Zyex is that the outer wrapping  materials in Zyex tennis string tend to be much less durable than the Zyex filaments inside  the string and do not bond with them. This can lead to the outer wrapping wearing away,  leaving the inner Zyex filaments.

Natural gut

Animal intestine is the most resilient material used to make tennis strings. It has better  tension retention than any other material, and also is softer than any other material used  for tennis strings. It provides the most energy return, meaning it is the most efficient  string. It remains soft at high tensions while other materials tend to stiffen dramatically.  This allows gut string to enable players to string rather tightly to improve ball control  without losing much rebound efficiency (power) and without greatly increasing impact shock,  which can hurt the elbow and other joints. Its principal drawbacks are much higher cost to  manufacture and purchase than other materials, weakness to shear stresses from off-center  hits (typical of beginning players), variable quality control depending upon the brand,  batch, age, storage conditions, and grade, difficulty of stringing due to its delicacy, and  poor durability when wetted with water. Natural gut is very sensitive to different types of  weather and those players who use it normally carry several different racquets with  different tensions to compensate for this. Some players, particularly those who hit flat  shots and hit the sweet spot consistently, find high-quality gut to be more durable than  many other types of strings due to its outstanding tension retention. This may help to  offset the high initial cost. The use of a dense string pattern also generally improves the  longevity of natural gut. Natural gut is produced by drying fibers extracted from a part of  the cow intestine called the serous membrane, or serosa, which contains collagen designed to  withstand the stretching and contraction of the intestine. It is this elasticity that makes  the fibers useful for tennis string. Sheep intestines have also been used for racquet  strings in the past. A general name for this material is catgut. The first natural gut  tennis string was rumored to be manufactured in 1875 by Pierre Babolat, who would launch the  VS brand of gut fifty years later. Natural gut is usually offered in coated form, to reduce  its tendency to unravel, particularly when humid or wet.

Gauge

The "gauge" number determines the thickness of the string. A string rated with a high gauge  number is a thinner string, and vice versa. Thinner strings typically offer higher  performance but break more frequently than thicker strings.

Stringing pattern

Virtually all modern racquets are strung in a criss-cross horizontal-vertical pattern.  Various other patterns have been used in history with varying success.

Double strung tennis racquets were introduced in 1977 but the "spaghetti racquets" were  later banned because they permitted excessive spin and were too successful. However, a  modern version of the double strung racquet has been introduced that is legal to use. 

Racquets are strung either with two separate strings (and thus four knots), or with a single  string (resulting in only two knots). Sometimes, a hybrid of two different string types may  be used in the same racquet. Traditionally, a double half hitch has been used to tie off  tennis string, along with a starting knot. Recently, new kinds of knots have been used  called the "pro-knot" and "Parnell knot". Along with the use of a starting clamp, this can  make all the knots identical, and improve the aesthetics of a string job.

String tension

The "string tension" of a racquet, usually expressed in pounds, indicates the pressure under  which the strings are secured to the frame. The string tension affects a racquet's playing  characteristics, such as the "feel" of the ball, control over the ball, as well as  maximizing power.

A loosely strung racquet will usually have a larger sweet spot and will hit farther but,  when swung hard enough, it will shoot balls unpredictably; a tighter string job will help  make delicate shots with more finesse and control.

An extremely tightly strung racquet cuts down on a tennis player's feel on the ball, but can  give the player excellent control if swung hard enough, with a smooth stroke. Such tension  may make delicate shots more difficult, but makes play from the baseline more constant.  However, if a player often hits powerful shots, a tightly strung racquet may quickly tire  the arm, possibly resulting in tennis elbow.

Many professional stringers advise players to string racquets with the lowest tension  possible while still being able to maintain control of the ball. Beginning players trying to  find their tension should start in the middle of the recommended tension range and adjust  the tension from there to meet their needs. The recommended tension is usually printed on  the racquet. With a lower tension the racquet will have more power and less control; with a higher tension, it will have less power and more control.

Restringing

Due to the tension present on the strings, elasticity and tension begins to decrease the  moment they are installed in a racquet. "Dead strings", or strings which have lost their  tension, cut down on the performance of a racquet. Dead strings may also hamper a tennis  player's ability to generate power and pace, and may even make their arm sore.

The frequency of restringing depends on the player and the racquet, but there are a few  recommended intervals. One is to restring the racquet as many times in a year as the player  uses it in a week; e.g., if the racquet is used three times per week, it should be restrung  three times per year. Another guideline is to restring after every 40 hours of play; if the  racquet is used three times per week and three hours per session, it should be restrung  approximately every five weeks. If the player has access to a tennis string tension meter  (or access to a pro shop equipped with one), he may restring his racquet after he measures a  loss of 25% or more of stringbed stiffness. However, many players who hit the ball hard  enough to break the strings simply restring rackets whenever the strings break.

Upsides & Downsides of the various string types:

Polyester 

Upsides: Durable. Lots of control. Lots of spin. 

Downsides: Low powered. Harsher on the arm. Loses tension faster. 

Multi-filament 

Upsides: Very good playability. Wide range of price points. Softer on the arm. Very good tension maintenance. Closest thing to natural gut. Downsides: Less control oriented. Certain multi-filaments can feel "mushy." Lacks durability for bigger hitters. 

Synthetic Gut 

Upsides: Economically priced. 

Downsides: Average overall performance and playability. Not extraordinary in any category. 

Natural Gut 

Upsides: Optimum playability. Holds tension the best. Easy on the arm. Playability even at very high tensions.

Downsides: High priced. Low durability.