Tennis EquipmentTennis Strings

Polyester Tennis Strings

An in-depth guide to polyester strings and some of the best poly strings on the market right now.

In the last 25 years, polyester strings have shifted from a relatively unknown product to the most widely used type of tennis string on the ATP and WTA tour.

This in-depth guide will take a closer look at polyester tennis strings and why they surged in popularity.

It will also look at the pros and cons of their usage for your typical club player, the different types of poly strings available and my recommendations for some of the best polyester strings on the market right now.

Let's take a look.

The History of Polyester Strings

Guga Kuerten

The first mainstream manufacturer of polyester strings was the Belgian firm Luxilon Industries & C°. The Flemish company originally produced yarn for the textile sector and medical applications.

However, in 1987 they added high-tech filaments to their product range, including amongst many other products; tennis strings.

While their first tennis strings weren't technically polyester, in 1991 they launched Big Banger Original, followed by Big Banger Alu Power in 1994.

Ten years later, in 1997, Luxilon were propelled onto the international stage thanks to an unknown 20-year-old from Brazil named Gustavo Kuerten.

Kuerten won his first of three French Open's that year, thanks in part to his roundhouse backhand that was capable of producing vast amounts of topspin. The reason? Kuerten had a new string in his Head Racquet: a purple co-polymer monofilament string called Luxilon Original.

While not the first player to use this type of tennis string, Kuerten was the first to enjoy Grand Slam success thanks to this ultra-stiff thread made from a polyester-like material.

The string allowed the man they called ‘Guga' to swing as hard as he wanted, while also creating the topspin needed to keep the ball in, much to the dismay of Sergi Bruguera whom he defeated 6–3, 6–4, 6–2 in the final.

With that success, Luxilon didn't remain a string purely for the clay-court specialists and in the year 2000 when Kuerten defeated Sampras on Pete's favoured indoor hard court, it's usage was becoming increasingly widespread.

Fast forward to today, and every tennis string manufacturer produces a polyester string in their lineup. And virtually all of the top players use it in their racquets to some degree.

Most players string with polyester in a hybrid setup alongside a natural gut to blend the control of the poly with the power of the gut.

Roger Federer is widely considered as the pioneer of a hybrid setup which has seen the likes of Novak Djokovic, Andy Murray, Grigor Dimitrov and Serena Williams follow suit.

For others, they've gone full polyester. Rafael Nadal, Stan Wawrinka, Milos Raonic and Nick Kyrgios all play with a full-poly setup on the ATP Tour.

What is a Polyester Tennis String?

Luxilon Alu Power

All synthetic tennis strings are made from polymers, which are essentially long chains of monomers, which is why poly strings are often called monofilaments.

Monomers are small, single molecules. Bonding these single molecules into a long-chain is called polymerisation.

For poly strings to reach their final finished product, manufacturers like Luxilon use polys comprised of ester functional groups— for example, polyethylene terephthalate (PET polyester), co-PET, and thermoplastic polyester elastomers (TPE). 

The manufacturing of a poly string is quite a lengthy process, and while not as labour intensive as natural gut, it is a multi-step process that involves sourcing the materials (they arrive as pellets), extrusion that turns them into a molten state, drawing to stretch and thin the filaments, coating and sizing, followed by post-processing before the finished product can be packaged and sold.

For a more comprehensive look at the process take a look at this guide: How Synthetic Strings Are Made.

What are the Benefits of Polyester String?

Wawrinka Backhand

With so many professional players opting to use polyester strings, they clearly have some advantages compared to natural gut or other synthetic strings.

Pros and many advanced level tennis players opt for polyester strings for a variety of reasons, but generally, the top three are:

  • Topspin
  • Control
  • Durability

Topspin Generation

A polyester string has two properties that are beneficial to topspin potential:

  • Low power (how much energy is transferred to the ball)
  • Low Elasticity

The lower energy return to the ball means players have to swing faster and harder to get the same amount of depth on their shots as they would with a more powerful string. That, in turn, means more racquet head speed, which influences the amount of topspin a player can generate.

Polyester strings are also stiffer (and often textured or angular in shape) this allows the strings to bite the ball more on contact and apply more spin.

Alongside that, because they have a slicker texture, the strings will move and then snapback at contact, which again enhances topspin generation.

Of course, players still need the required technique and racket head speed to take advantage of this, but if present, polyester strings are capable of producing much higher RPMs compared to other strings.

That extra topspin offers two significant benefits to a player as firstly they'll get a heavier shot that bounces higher and pushes opponents further back in the court.

Secondly, topspin provides a greater net clearance which means a higher margin for error, both for keeping the ball away from the net, and for bringing it down to the court before it sails long.

Control

With that increase in topspin potential, many players also find that stiffer strings are better for controlling the ball.

With less flexibility in the strings, the ball spends less time on the string bed promoting a more consistent response.

Durability

The final characteristic where polyester performs well is it's durability. Compared with natural gut, polyester strings are much harder to break.

Strings generally snap when they rub against each other and notch due to the friction. However, polyester strings are less abrasive than other strings.

Some of the first polyester strings that were monofilaments were incredibly durable but not the most playable strings.

As polys have evolved into monofilament strings with various additives, they are still long-lasting, but are now much more comfortable to play with.

Still, the top pros don't care much about durability. They restring so frequently and switch racquets during matches —meaning that string longevity is barely an issue.

What are the Drawbacks of a Polyester String?

Spin, control and durability. That sounds like the perfect string for many players but are there are any drawbacks? Yes, and like the advantages above, there are three main disadvantages to polyester strings. They are:

  • Require Good Technique
  • Tension Maintenance
  • Comfort / Playability

Require Good Technique

The first caveat with many of the stiffer polyester string is you need a decent technique to reap the benefits. That means the ability to generate good racquet head speed.

That's not an issue for pros, but at club level, many players are hitting the ball in an unorthodox style. 

If they were to play with a poly string, it would feel like hitting the ball with a table tennis bat. That's why for club players who insist on poly, it's recommended to string at reasonably low tension to alleviate some of the inherent stiffness.

Tension Maintenance

Because polyester string does not have much elasticity, tension loss happens quicker compared to other strings.

For recreational players who don't restring often this is bad news as they will be playing with a dead string that has less control, less power and is not arm friendly.

Tension loss happens even when the racquet hasn't been used, and polyester usually falls off a cliff after a few hours playing. 

Comfort / Playability

Another disadvantage of polyester strings is that they're stiff, which means they're not comfortable to play with.

Polys are stiff even when they're fresh out of the packet but to further compound that; the string has a ‘playing life' in your racquet. Generally, this falls between five and twenty hours before it goes dead.

Once the strings become elongated and reach their elasticity threshold, they become hard and even harsher on the arm.

Visually, the strings look the same, but the player has to swing harder to achieve the same amount of power and spin compared to a freshly strung bed of polyester. This can lead to injury.

This is becoming an increasing problem among junior players. Kids want poly strings to hit with spin like their idols and parents like it because it doesn't break as quickly.

However, they don't restring often enough and play with it long after it is dead. This can lead to arm issues even amongst younger players.

Who Should Use Polyester Strings?

Nadal RPM

So who should use polyester tennis strings? As usual, there's no right or wrong answer. If any of the advantages I listed above are appealing to you, then you should buy a set (see my recommendations below), string up your racquet and see how you get on. You won't know whether or not you like them without giving them a try.

There are a couple of things you should ask yourself first:

Do You Have a Proper Technique?

Most players turn to polyester due to the spin potential. While it's undoubtedly true poly will maximise spin, if you aren't able to hit topspin with natural gut or whatever other string you are using, then the poly will make no difference.

You will only see topspin increase if your technique is correct and your racquet head speed, is sufficient. If you're hitting with a continental grip with slow swings, for example, switching is unlikely to be beneficial.

Do You Suffer From Wrist, Elbow or Shoulder Problems?

If you're suffering from any tennis-related arm injuries, then the chances are you will not enjoy the feeling that polyester strings offer.

As I've said, poly's are very stiff strings, and you'll find your arm absorbs more shock and because they don't deliver much power, you'll have to work harder to achieve the depth and pace of shot to trouble your opponent.

Combine that with the fact tension loss is quick and they go dead faster unless you frequently restring you're going to magnify the adverse effects.

Do You Have the Budget?

Because polyester strings are durable, players gravitate towards them as they think they'll need to restring less.

However, since polyester tennis strings don't do as good a job at holding their tension, they'll go dead faster than other strings, which can create a false economy.

In many cases, a natural gut or a multifilament can work out cheaper as although they break quicker; you can get more playtime out of them.

The Difference Between Polyester and Co-Polyester

Rpm Blast Construction

Co-polyester strings are polyester tennis strings that combine various additives to change their playability in the racquet. For example, to make them softer, more elastic, or better at tension maintenance etc.

Whereas a pure polyester string refers to monofilament made from a single polymer called polyethylene terephthalate (PET). A co-poly string is made from polyester and other additives like olefins, plasticisers, elastomers to change the characteristics of it.

Without digging into the manufacturing process, the best way of looking at a co-polyester string is one that has been designed to avoid some of the problems offered by monofilament polyester strings.

How To Make the Most of Polyester Strings

String Tension Choice

If you have decided to take a punt on using polyester to see if it works for your game then there are three things worth considering:

  • The tension you string it at 
  • The gauge you use
  • Whether to use them in the crosses or mains in a hybrid setup

Tension

Polyester strings have high dynamic tension. That makes the stringbed stiffer and gives it a more board like feel.

The trend on the pro tour has seen the average string tension for a poly move lower over time. A decade ago, the average poly was strung at 55 pounds; this is now down in the 40s. And numerous players are competing with tensions in the 30s or even lower.

That doesn't necessarily mean you should copy them, because how often you play, racquet head size, climate and the type of poly you use all factor in deciding the ideal string tension.

If you're switching from a soft string strung at a high-ish tension to a polyester, then I'd recommend dropping the tension by around 10%. This will soften the string bed for a more forgiving feel at contact. 

However, some softer poly strings, for example like Luxilon Element, can get a bit ‘launchy' from the trampoline effect when the tension is too low, so you may need to experiment.

In general, if you're stringing soft strings in the 50lbs+ plus range, I'd drop 10% with poly and see how you get on. Just try not to get your racquet freshly strung then not use it for a few weeks as the racquet loses tension even when it's sat in your racquet bag.

Gauge

Broken String

The gauge of a tennis string is how thick it is, which can range from 19 to 15 with lower numbers being thicker. Nadal, pictured above, uses 15 gauge RPM Blast which is the thickest available. 

The thicker the string, the more durable it will be, while thinner strings will offer more spin and a livelier feel as they are wider spaced and can move more.

You'll also likely see more ball pocketing and a slightly higher launch angle from the stringbed on thinner gauges.

So is one gauge better? The key as always is to experiment. Some strings are shaped for more bite; some are rough, some racquet string patterns are denser, others are looser which all go hand in hand with the string gauge itself.

In general, I'd say if you're a string breaker, then go with a slightly thicker gauge string. You could also experiment with a thinner gauge in the crosses and a thicker gauge of the same string in the mains.

However, the gauge is not something I recommend thinking about too much. You'll see hundreds of posts online from other players saying “I get more spin with the thicker string” “I get more spin with thinner” etc. so as always, it's anecdotal. Don't read into it too much, just try a couple of different gauges (16 and 17) and pick your favourite. 

Hybrid Polyester String Setups

federer hybrid

The beauty of stringing a tennis racquet is that it doesn't have to be done with a single piece of string.

Most stringers prefer using two pieces of the string even if they're using the same string in the crosses and the mains.

This also brings about the possibility of hybrid string setup where you can use polyester in the crosses or mains, and combine it with a softer string.

This setup is widespread on the pro tour with players fusing two types of string, e.g. a natural gut and a polyester to bring out the best features of them both. In this case, the power of the gut and the control of the polyester.

For more on hybrid strings, read the full guide on them here.

Polyester in the Mains or Crosses?

Champions Choice Hybrid

If you are planning on using a polyester string as part of a hybrid setup, then should you use the poly in the mains or the crosses like Federer?

The main strings on the racquet do more of the work and therefore dominate the playability of the frame. So on that basis, you'll need to decide which strings characteristics you want more of.

For example, many players who use a soft natural gut will be interested in experimenting with a poly hybrid setup, but still want to keep the power from the gut. If that's you, then you could keep the natural gut in the mains and then string the crosses with polyester.

On the other hand, if you're looking for more control and topspin but still want a little bit of comfort, then you could string the polyester in the mains and the multifilament in the crosses.

As is often the case, it boils down to personal preferences, budget, restringing frequency and the specific characteristics of the two strings you combine for the hybrid.

Examples of Polyester String Setups on the ATP Tour

Around 80% of professional tennis players use polyester tennis strings. Many play with full beds of polyester, and others use a hybrid setup. Here are some of the polyester strings used by the top players:

Player Mains Crosses
Roger Federer Wilson Natural Gut Luxilon Alu Power Rough
Novak Djokovic Babolat VS Team Luxilon Alu Power Rough
Rafael Nadal RPM Blast RPM Blast
Dominic Thiem RPM Power RPM Power
Daniil Medvedev Tecnifibre ATP Razor Code Tecnifibre ATP Razor Code
Nick Kyrgios Yonex Poly Tour Pro Yonex Poly Tour Pro
Kei Nishikori Wilson Natural Gut Luxilon Element

My Top 8 Polyester Tennis Strings

Here are my top eight polyester strings I think are worth testing in your racquet.

These are my picks, and there are hundreds of great polyester strings on the market from a myriad of different brands. I could easily have picked more from the likes of Toalson and Pro's Pro but here are my top eight:

Tecnifibre Black Code

Tecnifibre Black Code

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Tecnifibre Black Code is a shaped co-poly that does a nice job of grabbing the ball. Although you'd class this string as a typical low-powered poly, you do get a feeling of elasticity when it's freshly strung, partly due to Tecnifibre's Thermo Core Technology.

The ball impact is more on the muted side rather than “metallic”, and it's not uncomfortable. Black Code is not the type of string I would suggest to someone learning the basic strokes or in the early stages of game development, but it does work well in hybrids for intermediate players.

Read Rui's full playtest of Tecnifibre Black Code 4S

Key Features:

  • Decent tension maintenance
  • Not too harsh on the harm
  • Plays well in hybrids

Volkl Cyclone

Volkl Cyclone

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Volkl Cyclone is user-friendly co-poly and is very well priced. I'd say it's fairly similar to RPM Blast from Babolat. Perhaps not as good at holding tension but at half the price it's hard to find any faults with this string.

Like RPM Blast, Volkl Cyclone's playability is there from the word go and for a player testing polyester but still wanting some comfort and power Cyclone is as good choice as any.

Key Features

  • Wallet-friendly
  • Plays well straight out of the packet
  • Good enough tension maintenance ~10 hours

Gamma Ocho

Gamma Ocho

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Gamma Ocho, as the name suggests is an octagonal shaped string with eight sides designed to provide maximum spin and control. 

This is one of the firmer strings in the list and isn't the easiest to play with. However, you get excellent spin potential, good durability, and it holds tension well.

Key Features

  • Eight sided string with well-defined edges
  • Great at holding tension
  • Low power

Dunlop Black Widow

Dunlop Black Widow Pack

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Dunlop Black Widow, like Gamma Ocho, is a shaped polyester, this time with seven sides which glide over each other smoothly to produce a very playable poly.

While you can't call it a ‘starter' string directly, it's certainly a good starting point for testing out polyester for the first time.

Dunlop Black Widow also a good choice as any for players who may have used poly in the past and found it too stiff as it lets you feel the ball.

Key Features

  • Great all-rounder
  • Let's you feel the ball
  • Works well in hybrids

Babolat RPM Power

Rpm Power

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One of the newest strings to the market is Babolat RPM Power. First seen in Dominic Thiem's racquet in 2019, it is is instantly recognisable due to it's copper colour.

Babolat RPM Power is a very comfortable polyester, and while you can't say it's powerful, it's certainly above average.

It also has a special coating that seems to help create a good level of spin and snapback. This also makes it easier to string if that's part of your consideration when buying.

Key Features

  • Good comfort
  • More power than your typical poly
  • Easy to string with

Luxilon Element

Luxilon Element

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Luxilon Element is extremely similar to RPM Power and like the Babolat version it's a soft poly. For players who want a user-friendly control oritentated string but with some feel and all-around responsiveness, Element is a solid choice.

Tension maintenance is not the best, and it's not the most durable string compared to some of the heavier duty poly strings. Still, for that blend of spin, comfort and power, Luxilon Element works well for a lot of intermediate and advanced players.

Key Features

  • A good option for those who've had arm problems with other polyesters
  • Good levels of feel
  • Not the most durable

Solinco Confidential

Solinco Confidential

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Another newcomer to the poly scene is Solinco Confidential. The American firm has several strings on the market such as Hyper-G and Tour Bite and recently added Confidential to form a trio of polyester strings that are widely used both recreationally and on the pro tour.

Solinco Confidential is probably the best string for tension maintenance in this list and is one I'd recommend all polyester fans give a try.

The guys over at Tennis Spin call this string predictable and from my impression after testing a set that is the perfect way to describe it.

No funky launch angles or erratic shots, just a steady response that gives you a lot of confidence of where the ball is going if you make solid contact.

Key Features

  • Excellent tension maintenance
  • Predictable response
  • Stiff but not a string you'd call uncomfortable

Babolat RPM Blast

Rpm Blast Specification

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RPM Blast is one of my favourite polyester strings that strikes a balance firmness and response. It's very firm without getting uncomfortable and dampened in just the right measure to kill harsh vibrations, but not so much that it takes away the feedback.

The power return is average for polyester, but you'll get copious amounts of spin at your disposal. Interestingly it gets pretty mixed reviews on the forums with many saying it's overrated, but I've always been a fan. I think the main gripe is the price as compared to Volkl Cyclone it's not wallet-friendly.

However, if you have the tools, RPM Blast will give you all the control you want.

Read Rui's full Babolat RPM Blast Review.

Key Features

  • Nadal's string of choice
  • Firm but still offers some feedback
  • The string I use most often

Frequently Asked Questions

Some commonly asked questions around polyester tennis strings.

How long do polyester strings last?

This is dependent on the string used as the various types of polyester, and co-polyesters strings all behave differently. It also depends on how tightly they are strung and how hard you hit.

The general rule of thumb is that polyester strings will play well for between 10-20 hours of play.

From my testing, typically for the first 10 hours, the strings play well and then somewhere between the ten and 20-hour mark, playability drops off a cliff completely. It's rarely a gradual decline, just a sudden drop in tension and the strings are virtually dead.

When can kids start using polyester tennis strings?

I would not recommend using a polyester string until a child is around the age of 16. At least not a full bed of it.

When young children are growing, they put an enormous strain on their bodies. Their muscles and bones are developing at different rates too, so this is a time to be careful and not hinder physical development.

Children also recover extremely fast so you might not think there are any problems should they use a polyester string, but in terms of injury prevention in later life, softer strings are a better idea.

It's also not unheard of to see junior players developing arm and shoulder problems purely from the wrong string at the improper tension.

If your child is breaking strings for fun and has a lot of strength in their game, a softer poly in a hybrid is a good starting point. Just remember you do need to restring often as the string goes dead.

Finally, I would also say using a more feel orientated string is useful for the development of touch, hand skills and volleys. Something severely lacking in the modern game.

How do I know when polyester strings are dead?

If the strings go dead during play, you should be able to get feedback instantly that it's time to switch.

You'll start to see notching in the strings, more of a board like feeling when hitting the ball, less snapback (so you will need to adjust the stringbed between points manually) and you'll also start to hit more erratically.

This is typically anywhere between 10 and 20 hours after a fresh string job.

What is the best way to string and weave polyester tennis strings?

Some polyester strings are notoriously tricky to string with, Dunlop Black Widow, for example, is a real pain when stringing a full bed of it. 

There aren't too many tips or trick other than practice, practice, practice. However, when weaving crosses, stringing one string ahead does make the job both quicker and more comfortable. 

It's also easier to pull the weave, rather than push as you do with softer strings. The video below offers some excellent tips that are easier to follow along with rather than read about:

So there you have it, an in-depth look at polyester tennis strings. If you have questions, please leave them in the comments below. Also, let me know your experiences with polys and whether you think I've missed anything.

Jonathan

Huge fan of Roger Federer. I watch all his matches from Grand Slam level right down to ATP 250. When I'm not watching or writing about tennis I play regularly myself and have a keen interest in tactics, equipment and technicalties of the sport.

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10 Comments

  1. Hi Jonathan, Great article! But I think you got the Gauge numbers wrong. The higher number is the thinnest string. Thus, Nadal probably uses the THICKEST string (15). Regards, Morten.

    1. Thanks, good spot I had it the wrong way around, now corrected. Dunno why as I’ve just written about Nadal using thick string on a previous post, but tbh writing this much about polyesters was more painful than stringing both my racquets with them so I need to proofread it again 😀

  2. Yay! All you wanted to know about polyester strings but were afraid to ask.
    I see you liked Black Code. I also liked that one a lot, but no so much in the newer “4S” version. In fact, the first version is the only string until now that made me shout “wow!” when I first tried it on my trusty Dunlop M5.0. After a couple of months I was pretty much done with it as it got very uncomfortable, but it was great while it lasted.
    Unfortunately, that was a one-off experience as the club stringer no more stocks it.
    (Just one remark though: polyester strings are all virtually constructed as monofilaments: a single “rod” instead of twisted thin filaments as most nylon strings are. An exception I recall is Tecnifibre’s Duramix, a multifilament polyester but that seems to be the odd ball)

  3. Great post as always. I really liked your poly selections, can’t go wrong with a lot of these. I wanted to suggest a few more like Volkl Cyclone Tour, Prosupex big ace and big ace micro, prince tour XT all of which are quite soft. I typically use Volkl CT as a full bed, the rest as cross strings for gut/multifilament mains. Two other strings which are more of an acquired taste for me are Goldenset snakebite and Weiss cannon ultra cable both of which I now use at 40-45 lbs in a full bed.

    1. Thanks, yes interesting on the stringing. I thought some players may pay in lieu of services.

      Btw, that’s a cheap rip off of the Christopher Clary article in the NYT so I’ve changed the link. Essentiallysports is a garbage Indian run site that just reworks and rips news from other sites.

  4. Hi Jonathan.
    Your next post could be about making a ranking of Federer’s best seasons, as you made it with his GS tally.

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