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Choosing A Tennis String


There are a number of factors to consider in choosing the appropriate string type to maximize your game: Composition, Gauge, Tension, and Construction. Each of these factors affect the durability of the string, and the power, control, and feel of your shots. There is a tradeoff between the durability and playability, because factors that make a string more durable (polyester or kevlar composition, higher gauge, and lower tension) also make the stringbed less elastic and create a more blunt feel when you strike the ball.

Strings tend to break because of two reasons. The first is that each time you hit the ball, the cross strings dig slightly deeper into the mains. Eventually, after numerous hits, the crosses cut right through, and one of the mains breaks. The second reason is that occasionally a mishit outside of the sweet spot will stretch a string enough to snap it.

Strings come in so many varieties because there is no single 'best' string out there. However, there is a best string type for each player's particular playing style, and as you develop your game and experiment with different types of strings, you will gradually discover which strings are best suited to your style.


Natural Gut: Natural Gut provides the greatest feel and playability of all string types and is very popular in hybrid stringing (see our article on hybrid strings) among professional players. It is very elastic, providing a lively, cushioned feel with high levels of both power and control. However, it's not widely used by recreational players because it's the least durable and most expensive of all the string types.

Synthetic Gut/Nylon: Synthetic gut is the most widely used type of string by recreational players because it provides a balance of durability and playability at a low cost. There are a wide variety of synthetic gut/nylon strings available, each offering different playability characteristics. Depending on how the nylon filaments or strands are woven, the strings can help provide more power, control, or spin. The two main types of nylon strings are Multifilaments and Solid Core. These are described in further detail in the "Construction" section below.

Polyester: Polyester strings are extremely durable, but the tradeoff is that they have a very stiff feel and a low power level. Many ATP and WTA Pros have been switching to polyester strings, especially Luxilon brand strings.


The string's gauge is a measure if its thickness (diameter). Thicker strings (lower gauge) offer more durability and control, but less power. Thinner strings (higher gauge) tend to break more easily, but provide greater power and a softer feel. A number convention is used in the U.S. for string gauges according to the following table:

String Gauge
Unstrung String Diameter (mm)
15 1.41-1.49
15L 1.33-1.41
16 1.26-1.34
16L 1.22-1.26
17 1.20-1.24
17L 1.16-1.20
18 1.10-1.16
19 1.00-1.10

Gauges 15-17 are the most common and most popular sizes. The L stands for "light," meaning it's a slightly thinner version of the gauge. Note that some of the diameter ranges overlap. This is because the actual diameter varies between manufacturers since there are no exact size standards set for each gauge. So if you're comparing different string brands, be sure to check the diameter measurement in addition to the numerical gauge.


Simply put, stringing at a lower tension results in more power, while higher tension results in more control.  However, if you go into the extremes results are not magnified.


Since Synthetic Gut/Nylon strings are made up of smaller nylon filaments, manufacturers have created a number of different types of synthetic strings by weaving or wrapping the filaments in a variety of patterns. As mentioned earlier, there are two main types of construction: Multifilament and solid core. Manufacturers have developed variations on these types to create different playability characteristics.

Multifilament strings are a bundle of nylon filaments without a central strand. These provide a soft, cushioned feel which is gentler on the arm, but as they wear down, they tend to fray because it breaks down one filmament at a time.


Multifilament Example


Solid Core Strings, on the other hand, do have a core nylon strand in the center and have one or several layers of smaller filaments wrapped around the center strand. Solid core strings are more durable than multifilament strings because of the central strand. Additional layers of wraps increase the durability.

Solid Core with Wrap

Other string types are essentially variations on these two basic types. There are multifilament cores with wraps, which are more durable than regular multifilament strings. There's also Textured string, which wraps one filament around the outer layer, enhancing spin and control.


Textured Example

Hybrid Stringing

Hybrid Stringing is the practice of using two different string types on the mains (vertical) and crosses (horizontal) of the racquet. This results in a blend of playability characteristics from each string that can't be found with a single string type. While any two strings can be blended in a hybrid, there are a couple things to keep in mind for the best outcome:

  • The mains are dominant in providing the overall feel of the hybrid, so use the string with the characteristics you want more of as the mains.
  • Mains and crosses can be strung at different tensions, but the mains should be a couple pounds tighter than the crosses. Do not vary the tensions by more than 5 lbs.
Hybrids are yet another method of getting one step closer to customizing the perfect racquet for your game, and below are a number of reasons why a player would want to create a custom hybrid:


Among more advanced players, the foremost reason to use a custom hybrid is to increase durability without sacrificing playability. The mains are usually the first strings to break since the crosses dig notches into them. So hybrids created for durability use a more durable string (like Kevlar or Polyester or a 15-16 gauge string) for the mains and a more resilient and playable string (like Synthetic Gut with a higher gauge) for the crosses. This makes the string durable, but the crosses soften up the feel making it much easier on the arm than a Kevlar or Polyester string alone. Kevlar and Polyester strings also retain tension better than Nylon, so this type of hybrid will feel more consistent over the life of the stringbed.


Custom Hybrids can offer blends of power and control tweaked to fit your needs. Professionals like Roger Federer or Andy Roddick use hybrids that offer controllable power, choosing a blend of Natural Gut with Polyester.