On strings and stringing

Racket strings in general

How rackets are restrung
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How string type, string pattern and tension can affect your game

Why and when strings break

How often should a racket be restrung?
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Question: Why have racket string?

Answer: No better way has been found to (i) reduce wind resistance as you swing the racket and at the same time (ii) minimise energy loss during the impact of racket and ball or racket and shuttle. A racket which was styled like a golf club, with a very small but solid head, might have low wind resistance but would be extremely difficult to hit a moving ball or shuttle with. And a racket with a steel mesh instead of strings would feel completely dead on impact, because the mesh would not stretch elastically as string does.

  • String pattern
Most tennis rackets have 16 cross strings (from side to side) and 19 mains (the long ones, from top to bottom). Badminton rackets have a denser stringbed, with 22 mains and 20 or 21 cross strings, typically, while squash rackets have only 12 by 17 or 14 by 18 strings. The strings in most rackets cross at right angles, although a few squash rackets have a fan pattern in which the main strings fan out from the throat.

  • How long is a piece of string?
One tennis racket requires 40ft (13m) of string and squash and badminton rackets take 30 ft (9m) each.

  • Sustainability and the Environment
Except for natural gut string, all racket strings are made of plastic (nylon, polyester or polyether) and are essentially non-recyclable. The only bio-degradable string is natural gut - it is, however, not a vegan choice because it is made from the intestines of a cow. (Grips are generally made of non-recyclable plastic too, with leather being the only biodegradable alternative. And better not to ask about tennis balls!) I cut all the string I take out of a racket into short pieces before disposal into the non-recyclable waste: that’s the best I can do. 

  • String construction
Badminton string and most squash strings are multifilament; tennis string may be multifilament or monofilament, or some combination of the two. Monofilament strings are made of a single, solid extrusion of material. Multifilament strings have no centre core but are made up of hundreds or thousands of strands of material twisted together. Most strings have an outer coating made of a layer of fibres twisted around the outside. 

  • What is the BEST string?
There is no best string. There is string which is better for one thing, but then it is worse in another respect (eg multifilament is “good” for tennis elbow but not as durable). Thinner string gives more feel (and possibly more power) but won’t last as long as thicker string. Some string is more expensive because it costs more to make or perhaps because of smart marketing, or both.
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  • What string do pros use?
The pros use exactly the same string as you and me. Not like their rackets: they don’t use the same rackets as you or I could buy (theirs are specially tuned and may even be frames which are not available to the public although they are painted to look like production rackets).

How rackets are restrung

(how long it takes, is it difficult, why does it cost so much)

You need a stringing machine to string a racket. A stringing machine must do three things: support the racket frame, pull the string at a specified tension, and clamp the string after each pull. 

  • Why does a restring cost so much?
A modern stringing machine such as my Wilson Baiardo costs several thousand pounds. And even though stringing machines are electronic and digital these days, there is still a lot of manual work involved in stringing a racket and it takes anything up to an hour to do one racket. (Badminton rackets take the longest because the string is so thin and there are many shared grommets; also the racket has to be inspected carefully for damaged grommets before starting - there are typically 76 of these - and any suspect ones individually replaced.) And string costs a lot even at trade prices (have a look on eBay – there are no bargains to be had). 

  • Is stringing difficult?
No and yes. Like all practical skills, the more experience a stringer has the better his (or her) work will be. No qualifications are necessary to become a stringer, but the UKRSA (UK Racket Stringers Association) and the ERSA (European) run training courses and certification for stringers. I taught myself and then, after I had strung a dozen or so rackets, I took the UKRSA training course.  I find tennis rackets the most straightforward to string although the string - particularly some polyesters – can be very stiff and difficult to handle; badminton rackets are the most fiddly and tricky, and also have the most strings, but they are the most satisfying to string. Squash rackets are less work because there are fewer strings but there is more variety in the string pattern and some are quite tricky to get right.

  • How do you know what the string pattern is?
The short answer is: experience. It does help if I receive the racket with the strings in place, and sometimes I take a photo before removing the old string. But I can usually see from the way the grommets have been distorted which way the strings should run (not an option with a brand new racket which has never been strung!). There is an online database: https://klipperusa.com/pages/racquet-stringing-patterns which has the string patterns for most (but not all) rackets. Another cheat I have used is to google the make and model of the racket and get a picture. 
Sometimes with badminton rackets I do have to check what the manufacturers recommend as the maximum tension: I don’t as a rule exceed this tension.

  • Two knots or four (one-piece or two-piece)
Any racket (with the exception of some squash rackets with the “power ring” at the throat) can be strung with a single piece of string and in this case there will be two knots, one anchoring each end of the string. Most rackets can be strung with two pieces of string, one for the main strings and one for the cross strings (two knots for each, so four in total), but the only reason for doing this would be if the mains and crosses were required to be strung at different tensions or if different string was required in either (a hybrid system). There is no other reason. (ATW is used on rackets which must be strung head-down).

  • A complete restring or just replace the broken one?
Sometimes all the other strings seem OK and still tight, and I am asked if I will replace just the broken one. This can be done but the tension is likely to be uneven across the racket; it is also fiddly because the unbroken strings on either side of the break must be re-tensioned and tied off, which takes time. All in all, this doesn’t cost very much less than a full restring and the result is not as good. (The same applies when one string has broken in a two-piece stringbed).
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  • Hybrid stringing?
This is when the mains and the crosses are strung with different types of string. (Roger Federer uses natural gut in his mains and polyester in his crosses.) It is said that hybrid stringing allows a player to have the best of both worlds – power from the mains and spin from the crosses, for example. However, I think the advantages are minimal and the significant disadvantage is that whichever is the softer string is worn through by contact with the harder material of the others, so they don’t last very long.

I would liken racket string to the tyres of a car – all the technology of the racket and the skill  and power of the player is communicated to the ball or shuttle by just the few square inches of the stringbed, in the same way as only a few square inches of tyre connect all the clever engineering of a car, and the skill of the driver, to the road. In other words, the strings are the business end of a racket, so it is worth getting the setup that best suits your style of play.
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  • Power
In tennis and squash, lower string tension gives more power. This is because string is more energy-efficient than a ball: a stretched stringbed gives back more energy than a compressed ball does. The higher the string tension the stiffer the stringbed so the ball crushes more, and energy is lost to the ball as heat (that’s why a squash ball gets warm).  
In badminton, tighter strings give a harder feel. Looser strings cause a slingshot effect which brings the flex of the racket more into play and the result is higher shuttle velocity, but with less accuracy. To get the same shuttle velocity with a more tightly strung racket, the player has to hit the shuttle harder. 

  • Spin
Because stiffer string (stiffer either because it is at higher tension or because it is polyester string, or both) is less efficient at repelling the ball, the player has to hit harder/swing faster. And because he hits harder/faster he can put spin on the ball. Polyester string is stiffer than synthetic gut or multifilament at the same tension and it is also better at “snapping back”, which imparts spin to the ball.

  • Many breaks occur at one of the points of contact between crosses and mains when the strings rub together which causes wear and fraying or notching (which of these depends on the string type, multifilament or monofilament). Because it is due to wear, this kind of break happens after quite a lot of use.

  • A break can occur when the ball or the shuttle is hit very close to the frame – there is no string on one side to absorb the impact, and it snaps.

  • I often see rackets with bumper strips which are worn or damaged by contact with the court. This happens a lot with squash rackets scraping the wall, and in the case of tennis rackets it is usually due to hitting or scraping the ground on the follow-through from a serve, or from hitting too low half-volleys. With badminton rackets it happens when the racket is used to flick a shuttle off the floor. And in all rackets such wear can be due to spinning the racket to decide who serves. The string may be recessed in a groove around the head of the racket but wear of the bumper strip or the frame itself over time can expose the string.

  • Something you see on a tennis court is a player (often a junior) flicking a stone or a twig off the court with their racket – a sharp edge on a pebble can damage or cut the strings. DON’T DO THIS!

  • Even the practice of alternately tapping one racket frame on the strings of another to compare tension can damage the string on the receiving end: the outside of a frame or bumper strip often has a few rough or sharp spots and it only takes one such to nick the string, which breaks some time afterwards – not often immediately afterwards.
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  • Broken or torn grommets cause strings to break, particularly in the case of badminton rackets. The function of a grommet is to provide a soft lining to the hole where the string passes through the frame, to keep the string from touching the hard (sharp) edge of the frame. The pressure of the string on the grommet can cut through the plastic to the frame beneath. I always check every grommet and on average I probably replace 5 or 6 individual grommets on every badminton racket I restring. 
  • When the strings are badly frayed. Only natural gut and multifilament string frays, and the fraying is the breaking of some of the hundreds or thousands of fibres that make of the string. When the string is new, the outer coat will protect the fibres but by the time fraying is visible this coat has been worn through and it won’t be long before the string breaks.

  • When the strings are badly notched. Notching happens with monofilament string, and notches form where the strings cross and are in contact. Notching is effectively the string being sawed through, so the string is losing strength as the notch gets deeper.

  • When the strings are moving a lot, and not returning to their correct up-and-down alignment.  Some types of string move more than others, and the tension also makes a difference to how much they move, but once they start staying displaced then it is time to renew them.

  • When the strings are old. Many recreational players play only occasionally and have been playing with the same racket for years and may never have had a restring (or it was so long ago they have forgotten when it was). Their strings may not show the wear described above. However, strings lose elasticity with time even when the racket is not used, because the internal structure of the string changes slowly due to it being in tension. (The tension drops as well, but this has less of a negative effect on the performance of the racket than the loss of elasticity). The result is that old strings feel as though the tension is still there but that is because they have become less elastic ie stiffer.

  • If you have developed tennis elbow. Dropping your string tension a few pounds will lessen the stress on your shoulder, elbow and wrist. (Thickening your racket grip also helps counter tennis elbow.)
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  • When you want to experiment, or if you feel your game needs a refresh. Just because you’ve always had your racket strung at a particular tension doesn’t mean your game won’t benefit if you change your tension by a few pounds. Particularly if you are also trying a different type or brand of string – though I think it is usually better to change just one thing at a time.