Types of Tennis Strings

May 26, 2023

The string you use in your tennis racquet and its tension can change its playability significantly. So it goes without saying they’re an extremely important part of your equipment to pay attention to.

In fact, just as much effort should go into the string you use as it does in choosing a tennis racquet. Why spend upwards of £100 or $150 on a new frame only to skimp on strings?

Spin, power, comfort, control and durability are all impacted by the type of string you use. However, strings are often overlooked with players stringing their frames with whatever the local stringer has cheap reels of or simply opting for a pre stung frame.

So what do you need to know about strings? What types of tennis string are there? What are tennis strings made of? Which strings should you choose? Let's take a look.

You can divide tennis strings into two main categories:

The oldest type of tennis string on the planet is natural gut and it's the string of choice for a lot of professional players including Roger Federer himself.

The Swiss Maestro strings with a hybrid setup of natural gut in his mains and luxilon in the crosses, which, much like his style of play, is a blend of old and new.

Natural gut strings are made of cows intestines and date back to 1875 when Pierre Babolat first used a sheep's intestine to produce them. Since then gut has become the benchmark for all other strings on the market for a number of reasons:

I’ve personally used natural gut in a number of frames over the years and have to say if you’ve never used it, you really should give it a go.

I like it for all the reasons above and because you can string gut fairly tight to get more control but you don't lose power as you do with polyester strings. You also don't feel any increase in jarring impact shock which can flare up tennis elbow.

So are there any negatives? Why are synthetic strings even used if the natural gut is so good?

The downsides are that natural gut is expensive and it doesn't perform well in certain types of weather.

The reason it's expensive is due to the high cost of manufacturing; this is an organic matter so to be turned into tennis string it's a labour-intensive process with multiple steps.

Another negative is that natural gut doesn't like wet or humid conditions. It can fray quickly once damp and degrades quickly. If you live in a wet or humid part of the world and play with natural gut, make sure you have a spare racquet with a synthetic string in case the weather gets bad.

Natural gut can also be fragile on off-centre hits. So if you’re a known string breaker, then it might not be the type of string for you. It's also quite difficult to string due to its delicacy,

The final negative is that gut can fall victim to variable quality control. This depends upon the brand, batch, age, how it's stored, and grade.

So what type of player is natural gut good for? Basically every type of player; no matter what your game. Very few people play it due to the cost and if you’re an aggressive baseliner with heavy topspin, then it won't last you very long meaning the price/performance ratio isn't a good deal.

For players who hit flat shots as they’ll find that high-quality gut is more durable than many other types of strings due to its tension retention. A dense string pattern will also improve the longevity of natural gut as there's less movement/friction in the string bed.

My Favourite Natural Gut String: Babolat VS Touch Natural Gut

Synthetic strings can be broken down into the following subtypes of string:

This is what most cheaper pre-strung racquets will come with. It's the cheapest string you can buy and is only really suited for complete beginners who play a handful of times a year and have no interest in strings or their tensions.

My Favourite Tournament Nylon String: None

The most commonly used type of string is synthetic gut which is made of nylon but not to be confused with tournament nylon.

As a ballpark estimate, I’d say 75% of all club players are using a synthetic gut string in their racquets as it's well priced and one club stringers will often bulk buy.

Nylon lends itself well to tennis as it has a number of dynamic properties and can be tweaked to produce different playing characteristics by the material it's wrapped in, and the angle it's wrapped at.

Generally speaking nylon strings with more than one wrap are higher quality than single wrap nylon strings. The number of wraps reduces the tension loss usually experienced with nylon strings.

If you are a player with a habit of breaking strings you won't find synthetic gut hugely durable and you might find it gets soft quickly too. But it's a solid string and for the typical weekend hacker, it's an ideal choice.

If you are new to tennis, then I recommend getting your racquet strung with Prince Synthetic gut and using that as the baseline to determine what you like and don't like, what you want more or less of. You can then try a natural gut or a multifilament to compare. You might find that synthetic gut works best for you.

My Favourite Synthetic Gut String: Prince Synthetic Gut

Multifilaments were developed to try and bring synthetic strings closer to the playability of natural gut. They’re manufactured by twisting together lots of microfibers and then wrapped in a resistant cover. They’re usually made of nylon but some manufacturers choose to incorporate other materials such as polyurethane, Zyex, Vectran or Kevlar.

The advantages of multifilament strings, when compared to single filament synthetic gut, are that they hold tension better, have a higher elasticity, and are more powerful. They’re also softer which makes them easier on the arm, so they’re usually a good choice to use for senior players.

The disadvantage is that multifilaments are more expensive and they’re not that durable. Once the outer wrapping is damaged, the string will start to fray and weaken.

My Favourite Multifilament String: Tecnifibre X-One Biphase

Polyester strings are the string type that most pros are using on the ATP and WTA tour. Rafael Nadal for example strings with a full bed of polyester but they’re probably not the type of string that regular club players should be stringing with.

Unlike multifilaments, a polyester string is a simple structure of single polyester fibre with a thin layer of coating. This is classed as a "monofilament" string and they come in different gauges (1.10-1.35mm) which varies the elasticity and durability.

Generally speaking, polyester strings have low elasticity and feel stiffer when compared to synthetic gut and multifilament strings. As a result, they’re significantly more durable and can be produced at much thinner gauges; so if you have the racquet head speed a poly string can help you produce wicked levels of topspin.

They do however tend to lose their tension quite quickly so your level of control decreases and the string will feel dead. Poly is not well suited for anyone with arm issues or injuries either. If your arm starts hurting with a poly, try a softer string.

With that in mind, polyester strings are only really well suited to players who string their racquets at a high frequency. For these players, polyester strings provide a great price/performance ratio.

In more recent times, polyester strings have had further development with the arrival of copolyester (co-poly) strings. This co-poly combination reduced the major weaknesses of polyester string: tension loss and lack of elasticity.

Luxilon is the main brand in the co-poly category and they have mixed a number of other materials like PEEK, carbon or metallic fibres to modify the playing characteristics. Almost every manufacturer carries co-poly strings in their product lineup today.

My Favourite Polyester String: Luxilon Big Banger Alu Power

Kevlar is the stiffest and most durable string available so for a string breaker who doesn't want to fork out $$$ for restrings every week, it's a viable option.

Kevlar has excellent tension holding properties but it's one of the harshest strings on the body and will likely cause tennis elbow.

For that reason, Kevlar is often strung in a hybrid setup with another string type to combine both strings’ qualities. I never use it and can only recommend it if you have no arm troubles, and other types of string are not lasting you long enough.

Example of a Kevlar String: Ashaway Crossfire 17 Kevlar String

As well as the composition of string, most strings are available in different gauges from the manufacturers. The gauge is the thickness of the string.

A string with a high gauge number is a thinner string and vice versa. Thinner strings generally offer higher performance (more spin) but are not as durable thicker strings.

If you’re shopping for strings online then you will see each string has a number with it, this is usually between 15 and 20 with the most common being 16, 17 and 18.

The vast majority of players use 16 or 17 gauge. You will also see the letter L used such as 16L. The L Signifies light which is basically half a gauge. So 15L is thinner than 15 but thicker than 16.

The thinner the string, the more bite you can get on the ball to generate more topspin. Depending on your technique, this will allow you to swing harder and keep the ball in play, Or it may result in you hitting with too much topspin and not having enough depth or penetration on the ball.

For choosing a string gauge, I recommend choosing the thinnest string that gives you adequate durability based on how often you are willing to restring.

If you are not breaking 15, try 16 and so on. If you feel like your groundstrokes have lost depth due to a thinner gauge string, then try reducing tension before going to a thicker string.

The more you play, the more quickly your strings will lose their tension or break. If you’re competing at a high level or money is no object, then you can go for the highest quality strings and restring as often as you see fit.

However, most recreational players with less disposable income should go for a durable set of strings that play well for a long period and still providing good levels of feel and playability without breaking the bank.

If you are using synthetic gut, natural gut, or a multifilament. The general rule of thumb is to restring as many times per year as you play per week. So if you play three times a week, you should restring three times per year. Another rule you may have heard is for every 30 hours play you should restring. Neither of them are golden rules and I personally tend to restring based on what string I am using and when I feel like it needs it.

If you use polyester then as soon as the strings stop snapping back into place, and need to be straightened between points, you should restring.

To get the best performance out of your racquet then the tension you string at can make a big difference. The tighter you string, the less power you have and the more control you have.

The looser you string you gain more power but also lose control. The key here is to experiment so should try different tensions; if you play better with looser strings – great! If you spray it all over you can try a higher tension the next time.

In terms of a starting point, if you look at your racquet you’ll see a recommended tension range printed on the side. That is there for a reason, and I recommend starting in the middle of the range. For example, if your racquet says 50 – 60 lbs. String at 55 lbs to start with. Or just slightly higher at 56 or 57lbs seen as though tension is lost quickly.

Feel free to go higher or lower than the recommended range if that is what you feel you need. If you are using a Polyester, then string looser than you would with a synthetic gut for example, but as you will have gathered from the rest of this post, string choice is a process of experimentation.

When choosing tension, you are generally going after two things – depth and control. If you’re moving forward and volleying, feel also comes into play.

You need to find a tension that allows your bread and butter groundstrokes to land deep in the court. It should not take huge effort to hit deep, you should be able to swing smoothly to achieve good depth. String tighter if you’re hitting long, string looser if you are hitting short.

Feel, is hard to define and relies on a lot of anecdotal evidence. Some players prefer the way a firm stringbed feels, some people like the way a soft stringbed feels. Again, test out tensions and see which you prefer.

There are a number of other factors which influence tension:

A hybrid is when two different strings are combined into one bed of string. A lot of pros use this set up right now right by mixing a strong, endurance string like polyester or Luxilon in the main strings and natural gut or a soft multifilament in the crosses.

Some players like Federer reverse the pattern with soft strings in the mains, and tough strings in the crosses producing a softer feeling. You have less durability with that combination but when you get a freshly strung racquet one game before each ball change that's not a factor.

Hybrids aren't exclusively for the pros either, they can lower the cost of an expensive string. If you love natural gut, but the price tag and the need for frequent restringing makes it hard to justify. Using cheaper, tougher nylon in the crosses will increase durability and lower the overall cost.

That's why you will see many string manufacturers prepackage hybrids with a length of natural gut and a length of nylon.

It's impossible to just make a list of the best tennis strings as what works for one player, won't for another. So if you’d like me to recommend a string, answer the following questions when you leave a comment below and I’ll be able to give you some:

The final thing to remember is that choosing a type of tennis string is about experimentation, use this guide as a starting point and try different strings out.