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View Full Version : Why do the pro's use 16L or 16 guage string?


nikolaih
10-23-2006, 10:38 PM
Looking at the pro stringing specs page from Wimbledon(http://tt.tennis-warehouse.com/showthread.php?t=110799&highlight=french+open+luxilon) I've notice that the pros predominantly use Lux ALU Power and Babolat VS Gut at 16L and 16 respectively. A couple of women use higher guage TiMo and Ace. The stringing report from the French Open was similar.

What's the theory behind them mostly using the 16 guage strings?

backcourt
10-24-2006, 05:15 AM
Looking at the pro stringing specs page from Wimbledon(http://tt.tennis-warehouse.com/showthread.php?t=110799&highlight=french+open+luxilon) I've notice that the pros predominantly use Lux ALU Power and Babolat VS Gut at 16L and 16 respectively. A couple of women use higher guage TiMo and Ace. The stringing report from the French Open was similar.

What's the theory behind them mostly using the 16 guage strings?
I suspect it is because they hit the ball so hard and with so much topspin that they would break 17g string really quickly.

neo
10-24-2006, 06:54 AM
Maybe because Luxilon Big Banger ALU Power is not available in gauge thinner then 16L (1.25mm)?

Ripper
10-24-2006, 07:33 AM
I remember earlier this year (was it during the French Open?), while on a practice sesion, Nadal couldn't understand why he was, constantly, hitting long. He asked the stringer about how he had strung his raquets. The string brand and model were correct. The tension was correct. So, what was wrong? The gauge! Instead of his usual 15L, his raquets had been strung with 16, a thinner gauge. So, they corrected this and everything went back to normal... Apparently, the thicker strings provide them pros with more control...

armand
10-24-2006, 08:04 AM
Why use poly? Answer: Because they're stiffer and deflect less. And so they want more of the same because a thicker poly is even stiffer.

nikolaih
10-24-2006, 11:23 AM
Maybe because Luxilon Big Banger ALU Power is not available in gauge thinner then 16L (1.25mm)?

Luxilon Ace seems to have similar material composition as BB Original and ALU, it has the fluorocarbon resin for example.

nikolaih
10-24-2006, 11:25 AM
It's interesting, the common thought seems to be that thinner strings have more 'bite', so one would naturally expect that the pros who hit with a tremendous amount of top would use thinner guages. But it seems that the 'power' imparted by thinner guages may be more than the 'bite' can make up for when pros use these thinner strings?

hummer23
10-24-2006, 11:29 AM
To me, a thicker string gives a more solid feel, you can plow through a bit better. I dont think durability is an issue, consdiering pretyt much any gauge string will get a player through 45 mins of hitting if they change with the ball rotions, or even through a match. Its about that solid feel i think.

Valjean
10-24-2006, 11:51 AM
Still, the early and common use was 15 gauge; then 16 was preferred once it was available. Sampras, anyhow, was always looking to go thinner than the 17 gauge gut he used.

Midlife crisis
10-24-2006, 11:52 AM
It's interesting, the common thought seems to be that thinner strings have more 'bite', so one would naturally expect that the pros who hit with a tremendous amount of top would use thinner guages. But it seems that the 'power' imparted by thinner guages may be more than the 'bite' can make up for when pros use these thinner strings?

There are a couple of things going on. It's been measured and reported by the USRSA here:

http://www.racquetsportsindustry.com/issues/200501/200501tension.html

and in particular this paragraph:

Fortunately, the spin generated for a typical ball-racquet impact can easily be measured. This has been done at the University of Sheffield in England, and the results showed that the spin on the ball is not dependent on string tension or string type. In that testing it was concluded that all stringbeds are sufficiently "rough" to achieve maximum spin for the given shot. Therefore, even if thin, sticky, and tight strings were used in an attempt to increase stringbed "roughness," there would be no actual increase in rebound spin.

so string gauge doesn't intrinsically affect the amount of spin generation.

However, some types of strings like polys do seem to produce a lot more spin. There are probably a couple of mechanisms that explain this.

The first is that stiff strings, like poly and kevlar, don't stretch much and so the ball must compress more during the impact. When a ball is compressed, its effective rotational radius decreases when it is flattened, and this will actually cause a higher rotational rate than a less flattened ball. As the ball rebounds and the contact pressure against the string reduces, a poly string's slickness can actually allow the ball to retain this higher rotational rate as it rebounds. So, you get "more" spin than your swing path would indicate.

Another mechanism is an assymetric pocketing of the ball. On a groundstroke, a ball will have a lot of topspin generated by hitting the ground. That rotational momentum can cause the pocket to deform in response to the spin, and then rebound so that the spin is reversed. This helps to add spin to the shot.

One last thing is that the materials used to make strings don't all behave linearly in response to tension. When a thinner gauge string of the same material as a thicker gauge string is tensioned to the same level, it can actually be stiffer than the thicker string. You can see this in the USRSA string guide, here:

http://www.racquetsportsindustry.com/issues/200609/200609stringselector.html

While it is generally true that the thinner gauge is usually less stiff, there are quite a few instances where there is no difference or the thinner string is actually stiffer.

I don't believe durability is of any concern to a pro. If you look at the trend of players to switch racquets with every ball change, and see that almost never will the string break before the racquet change, they would be well served to use a thinner string if it provides any benefits. The actual reality is that thinner gauges don't provide benefits for most situations.

nikolaih
10-24-2006, 12:08 PM
Interesting points.

Another factor could be the weights of various sized strings -- different guages seem to be a couple grams apart and so with a lower SW racquet, I could see a player being sensitive to a 4 gram difference or so. Pros seem to use a heavier SW so this difference would probably be less important.

backcourt
10-24-2006, 02:06 PM
Another mechanism is an assymetric pocketing of the ball. On a groundstroke, a ball will have a lot of topspin generated by hitting the ground. That rotational momentum can cause the pocket to deform in response to the spin, and then rebound so that the spin is reversed. This helps to add spin to the shot.


So Midlife, does this mean that when one hits a topspin shot on a ball that comes over the net with alot of topsin on it, the return shot will inherently have more spin on it than if one returns a flatly hit ball that is moving at the same pace?

Midlife crisis
10-24-2006, 08:45 PM
So Midlife, does this mean that when one hits a topspin shot on a ball that comes over the net with alot of topsin on it, the return shot will inherently have more spin on it than if one returns a flatly hit ball that is moving at the same pace?

Once a ball hit to you with topspin hits the ground, the spin will equalize so that the amount of spin is pretty well correlated with ball speed. The energy to make the ball pick up spin reduces the ball speed, so balls with already a lot of topspin don't need to slow down as much, whereas flatter balls slow down more when they hit. (The only exception to this is a ball hit fast and hard with a lot of underspin, in which case the low angle of contact with the ground will actually let the ball skid, so it may still have some backspin or no spin when it reaches you.)

In any event, almost every ball that comes to you after the bounce will have a spin rate that correlates with its forward speed, and it is this consistency that makes it easy to time groundstrokes and hit them back with a consistent trajectory.

But the answer to your question is yes, if you hit a ball back with the same swing trajectory and the incoming ball has more topspin, it should go back with a bit more topspin. This effect is greater the heavier your racquet is, but in any event is not that great no matter how heavy the racquet nor how elastic the string. The swing path is going to be a much larger determinant of the topspin going back, but this effect will help a little bit.

armand
10-24-2006, 08:58 PM
Hi midlife, interesting post, thank you. Please me to indulge the court in one final viewpoint:

A stiffer string will provide more spin because there is less loss of energy. If you are using a more lively string like a multi, the strings will pocket more, giving the ball more pace as the strings rebound back from their stretch moment. However, the strings also deflect in the direction of the plain of the stringbed as you try to put spin on it. And that energy is not recovered because there's too much friction in the stringbed for them to rebound(you have to straighten your strings after a few hits). And since they do deflect in the opposite direction of the ball(IE they will deflect down as you're trying to hit topspin), that energy is lost, while a stiffer string will stay in place so you don't lose that energy.

Feel me?

Midlife crisis
10-24-2006, 10:39 PM
Hi midlife, interesting post, thank you. Please me to indulge the court in one final viewpoint:

A stiffer string will provide more spin because there is less loss of energy. If you are using a more lively string like a multi, the strings will pocket more, giving the ball more pace as the strings rebound back from their stretch moment. However, the strings also deflect in the direction of the plain of the stringbed as you try to put spin on it. And that energy is not recovered because there's too much friction in the stringbed for them to rebound(you have to straighten your strings after a few hits). And since they do deflect in the opposite direction of the ball(IE they will deflect down as you're trying to hit topspin), that energy is lost, while a stiffer string will stay in place so you don't lose that energy.

Feel me?

I hope I didn't say that a stiffer string will provide more spin via less loss of energy, because there will actually be more energy lost during the impact. Strings are very efficient at returning energy when they are stretched, but the ball is more lossy when it is compressed and returns to its round shape, so stiffer strings result in less ball speed.

But your point about the strings deflecting at the contact point is valid, and strings that move may cause less but but will also cause loss of directional control. I think it's also been debated whether or not strings that appear not to move, such as a full poly stringbed, actually don't move during the hit or if they move and slide back into position, which if it does may actually help the spin. I'm not sure if there has been conclusive evidence either way that I've seen. I know that my last kevlar hybrid string job moved all over the place but I still seemed to get a lot of spin, maybe not quite as much as a poly but definitely moreso than a synthetic gut string. Some of that may be due to the lower power of the kevlar so I swung faster, and that makes it hard to discern how much difference the strings moving during the contact makes.

What's your experience?

armand
10-25-2006, 05:10 AM
I wasn't disagreeing with your previous post, I was just speculating on my own there, just wanted your honest opinion in case I was talking out of my ***.

I don't have that much experience with poly or different kinds of polys, but I am noticing that: Poly just grabs the ball better somehow. I'm not changing my swing but it does seem like I am getting more spin. Also, if I hit it offcenter(not a necessarily a mishit, nor a framer) I'm noticing a diagonal topspin(you know the ones; they bounce a little to the side, making it tough for your opponents) whereas those were rare with mult or gut.

Most spin I ever observed was a guy coming back from a long layoff and he was using an old cheap K-Mart racquet that had really loose strings. He had little control but some really crazy outta this world spin. But that's a story for a different thread I think.

Midlife crisis
10-25-2006, 11:58 AM
I don't have that much experience with poly or different kinds of polys, but I am noticing that: Poly just grabs the ball better somehow. I'm not changing my swing but it does seem like I am getting more spin. Also, if I hit it offcenter(not a necessarily a mishit, nor a framer) I'm noticing a diagonal topspin(you know the ones; they bounce a little to the side, making it tough for your opponents) whereas those were rare with mult or gut.

Most spin I ever observed was a guy coming back from a long layoff and he was using an old cheap K-Mart racquet that had really loose strings. He had little control but some really crazy outta this world spin. But that's a story for a different thread I think.

The extra spin you get may be a result of both the "overspin" that you can get with poly strings, plus the fact that being lower powered than the multis or gut strings that you use, you just swing a little faster. I know the kind of off-centered hits that you're talking about. I wish I could pull those off deliberately when I need them!

The loose strings will really create some wild spins. It's the basis of how spaghetti strings work. If only mere mortals could control the ball using tensions that low. . .

ChicagoJack
10-25-2006, 01:27 PM
Midlife - I think you and I have not only read the same books, but have come to the same conclusions about the grey areas. I still disagree with the oft heard notion that slippery strings ie. poly, or loose strings produce more spin via a snap-back effect on the ball as it leaves the string bed. It is a cogent, plausible argument but unproven, as far as I can tell. If anybody has a link or two on this particular point, I'd love to see that, and am open to the idea I am wrong on this issue.

I agree with everything else you mentioned here. Have actually posted the some of the same links as you have. Thanks for taking the time to lay this all out. Nice posting. Well done.

Best regards
-Jack

Midlife crisis
10-25-2006, 10:50 PM
Midlife - I think you and I have not only read the same books, but have come to the same conclusions about the grey areas. I still disagree with the oft heard notion that slippery strings ie. poly, or loose strings produce more spin via a snap-back effect on the ball as it leaves the string bed. It is a cogent, plausible argument but unproven, as far as I can tell. If anybody has a link or two on this particular point, I'd love to see that, and am open to the idea I am wrong on this issue.

I agree with everything else you mentioned here. Have actually posted the some of the same links as you have. Thanks for taking the time to lay this all out. Nice posting. Well done.

Best regards
-Jack

Thanks, Jack. I've appreciated your posts and the research you've brought to the forum. I remember a lot of very detailed and very clearly written posts with lots of references that you've put out there, and those have been very thought provoking.

As far as the "overspin" with poly strings, I recall wandering around the 'net looking for articles which might support this, and stumbled across one article detailing much the same phenomenon in golf. Golf clubs have a regulation that determines the maximum width and depth of the cuts in the club face, but this one article detailed how by slightly altering the physical characteristics of the face, you could get more spin by this overspin mechanism with no grooves in the club face at all by choosing appropriate coefficients of friction for the ball and club face, and by constructing the ball a little different so its rebound rate were altered slightly. However, the golf ball being so dense and the playing conditions being more diverse, this combination would not work for all shots, and for chips and softer shots, it would produce little spin and consequently little control. I also think some of the ball parameters were outside of the legal limits.

Anyway, when I take a ball and rub it across the stringbed of a poly job, it does slide more easily at lower pressures than against other strings, so at some point the ball is able to rotate independent of the strings but still in contact with the strings. The pressure at which this difference is noticeable is pretty significant, and you can see that the ball is compressed against the strings when this still occurs. This lack of grip at lower pressures might also explain why people to say that soft shots, like drop volleys, are hard to pull off with poly strings.

I don't see another obvious explanation for the amount of spin I can get from a full poly stringjob. It's more than I can get from a kevlar stringjob, even if the kevlar is lowered powered and I have to swing harder. Poly strings are too stiff to stretch much during the contact so the assymetrical pocketing isn't going to be as great as with softer strings.

What do you think?