Tennis string structure

This page explains the different types of tennis strings, their corresponding advantages and disadvantages, and their suitability for the different player types.

    The string market is large, and there is a huge number of brands offering a diversity of strings under their label. Every string has its unique characteristics. If you want to know more about specific strings, check out the string search or the discussion board.
    Although there are a lot of physical attributes (material, structure, gauge, color, surface etc.) that can be altered during string production, there are certain main features I want to describe below.
You can divide tennis strings into two main categories: natural gut and synthetic string.

Natural Gut

    Natural gut strings are made of cows' gut in a complex process. Their main features are superb elasticity, tension stability and "liveliness". But they are very expensive and sensitive to weather, while one has to say that a lot of improvement has been made in this respect during the past few years. Still many of the pros play natural gut, but I don't recommend natural gut for the normal club level player, since those players should use strings with better price/performance ratios.
    Examples for natural gut strings: Babolat VS TeamKlip LegendBow Brand Championship and Pacific Prime Gut.

Synthetic Strings

   Synthetic strings are mostly high tech products which are constantly being improved to bring their playability into line with natural gut strings but keep the advantage of the synthetic materials' higher durability. There's a great diversity of different structures and materials. Let me briefly explain the main categories:

Nylon Strings

Nylon Strings

    The most frequently used string type. Nylon strings are among the most reasonable tennis strings and are normally made of a single nylon core and various resistant wraps. Due to its excellent dynamic properties nylon (polyamide) is well suited as a material for tennis strings. The high number of different types of constructions (wrap material and wrap angle) influence the string's playing characteristics significantly. As a rule of thumb, nylon strings with multiple wraps can be considered higher grade than single wrap nylon strings. The wraps reduce the tension loss usually experienced with nylon strings. Nylon strings are suitable for players who have a normal or high string consumption.
    Examples: TOA Leoina 66, Wilson Championship NylonBabolat Powergy, and Prince Tournament Nylon.

Polyester Strings

Monofilament Strings

    Polyester strings show a fairly simple structure: they consist of a single polyester fiber with a thin coating. This type of construction is termed "monofilament". They come in different gauges (1.10-1.35mm) which enables you to choose among different elasticity/durability levels. Polyester strings are little elastic and feel quite stiff compared to nylon or multifilament strings, but on the other hand they provide significantly better durability, allowing for thinner gauges. Pure polyester strings like the Polystar Classic or the Kirschbaum Super Smash have one main downside: They tend to lose their tension quite quickly, so control decreases and the string feels dead after a short time of play. Thus polyester strings are only recommendable for players with high string consumption. For these players, polyester strings offer a great price/performance ratio.
    During the past few years, tremendous effort has been put into the advancement of monofilament strings and the elimination of their major weaknesses (tension loss and lack of elasticity). Luxilon has specialized in this string category. More and more polyester blends (co-polyester), mixed with a number of other materials like PEEK, carbon or metallic fibers, are being developed to modify the playing characteristics. Almost every manufacturer carries such strings in their program today.
    Examples: Luxilon Big Banger Alu PowerKirschbaum Touch TurboSignum Pro Poly-PlasmaPolyfibre Poly-HightecHead Ultra Tour.

Titanium Strings

    Shortly after the titanium boom in the racquet market, a flood of "revolutionary" titanium strings entered the string market. Based on Nylon or multifilament strings, the titanium is either applied with the coating of the string, protecting the material from UV radiation and abrasion, or the titanium is integrated into the filaments to modify the playability of the string.
    Since the titanium boom is over, titanium strings are no longer popular today. The term "titanium" in the name of a string often refers only to its color.
    Examples for "real" titanium strings are Gosen OG-Sheep JC TitanTyger Ultra Titanium (coating) and Isospeed Titanium (fiber).

Multifilament Strings

Multifilament Strings

    To bring synthetic strings' playability more into line with natural gut, many microfibers (which can be of many different materials) are twisted together to a string, which is wrapped with a resisant cover. Advantage: higher elasticity and better playability. Disadvantage: multifilament strings tend to break soon once the outer wrap is damaged (the strings "fray"). Also these strings cost more than nylon strings because of the complex manufacturing process. Tecnifibre has sort of specialized on that type of string. Other popular multifilaments are Isospeed ProfessionalHead FiberGelKirschbaum Touch MultifibreWilson NXT Tour and Babolat XCel Premium.

Structured Strings

Topspin String

    Structured (textured) strings are designed to provide better ball bite and thus enhanced spin. Most of these strings indeed offer great spin potential and in line with that better control, but unfortunately the texture usually wears within a short time and the strings become smooth. Another downside is their decreased durability.
    Examples: Kirschbaum Super Smash SpikyPacific Power HexIsospeed PyramidPrince Topspin Plus.

Hybrid Strings

Hybrid String

    Hybrid strings are a combination of two different strings for mains and crosses. In a uniformly strung racquet it's almost always a main string that breaks. This is because the main strings move a lot more than the cross strings so the cross strings "saw" into the main strings, causing notches and eventually breakage. That's why in hybrid strings usually a durable string is used as the main string (e.g. polyester or aramid/kevlar/technora). As cross strings usually highly elastic synthetic strings or natural gut strings are used to provide comfort and feel. Hybrids provide good playing characteristics while a poly/multi hybrid often lasts longer than a pure poly or pure multifilament string job.
    There is an almost infinite number of possible string combinations. As you can create highly individual combos, hybrid strings are becoming more and more popular. There are also some pre-packaged hybrids available from the major string brands.
    Examples: Pacific Poly Gut BlendVölkl Catapult FIREWilson HyperLast. Babolat offers the possibility to obtain "half" sets of the Pro Hurricane, the X-Cel Premium and the VS Team for individual combination (Custom+ Hybrid).

Some general stuff about strings

    To get the best out of your racquet you'll have to do a little more than just use the best string. The choice of the right tension is about as important as the choice of the racquet frame. As a general rule: the harder you string the less power you get and the more control you have. With lower tension you gain more power but also lose control. In any case you should try different tensions; if you play better - great, and if you don't, you can get back to the old tension the next time. To show you the effects different string tensions and diameters can have on your racquet's performance I created following tables:

String Tension Power Control Durability Feel Comfort
softer more less more more more
tighter less more less less less


String Gauge Elasticity Durability Spin Feel Comfort
thinner more less more more more
thicker less more less less less

    To increase the durability of your strings you should not expose your racquet to extreme heat, cold or humidity. Therefore you should always keep your racquet in its bag. To protect your racquet head you can use a head tape. This is useful if playing on clay court or if the strings are not protected enough by the racquet headguard.
    Strings lose elasticity with time, one type of string faster, another type of string slower. This has a negative effect on the playability; players with a sensitive arm will feel it soon. In general you shouldn't play a string longer than 2 to 3 months. Then it's about time to cut out the strings and restring your racquet.

Often the diameter of a string is not given in millimeters but in the old "gauge". Following table helps you convert between these two measures (without obligation):

Gauge Diameter approx.
15 1.43 mm
15L 1.38 mm
16 1.32 mm
16L 1.28 mm
17 1.25 mm
17L 1.20 mm
18 1.10 mm

© Jens Barthelmes

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