The numbers: softest and hardest strings by material

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Strings were strung at 62 lbs. Stiffness is the number before tension loss.


Stiffest Kevlar (non-blend):

Prince Problend w/Duraflex 16 (Main), 981, 16 lbs
Gosen Arammix Pro 16, 795, 19 lbs
Ashaway Kevlar 16, 764, 27 lbs

Softest Kevlar (non-blend) and/or Technora:

Forten Ultra Thin Blend (Main) 18, 545, 15 lbs
Forten Thin Blend 18/17 (Main), 557, 14 lbs
Wilson Hyperlast Spin 19 (Main), Technora, 562, 14 lbs

Softest Kevlar/nylon blend and/or Vectran:

Ashaway Composite XL Pro 15, 444, 16 lbs
Ashaway Composite XT Pro 16, Vectran, 470, 14 lbs
Pacific Powercraft 18, 508, 15 lbs

Stiffest poly:

Pacific Poly Force 16L, 320, 18 lbs
Gamma Dura Blast 16 , 303, 13 lbs
Babolat Revenge 16, 302, 19 lbs

Stiffest nylon monofilament ("synthetic gut"):

Ashaway MonoGut 16L, 242, 19 lbs
Wilson Ultra Synthetic Gut 15L, 238, 14 lbs
Dunlop X Life Synthetic, 236, 15 lbs

Stiffest nylon multi:

Wilson NXT Tour 16, 219, 9 lbs
Gosen Nanocubic 16, 217, 11 lbs
Alpha Sphere 16, 216, 14 lbs

Softest poly:

Babolat Pro Hurricane 18, 187, 22 lbs
Head Sonic Pro 17, 199, 23 lbs
Pacific Poly Power 18, 201, 21 lbs

Stiffest and softest poly blend multis:

Tecnifibre Promix 17, Nylon/poly, 199, 14 lbs
Isospeed Energetic 16 , Polypropylene/poly, 175, 19 lbs

Softest nylon monofilament core ("synthetic gut"):

Pacific Power Twist 16L, 175, 13 lbs
Head Synthetic Gut PPS 18, 176, 12 lbs
Pacific Power Twist 16, 179, 12 lbs

Stiffest and softest Zyex (sorry, Klip Zyex and Bow Brand were not tested):

Ashaway Dynamite WB 16, 165, 13 lbs
Ashaway Dynamite 17 , 147, 14 lbs

Stiffest and softest polyolefin:

Isospeed Control 16, 158, 16 lbs
Head Intellistring 17 (Cross)/Intellitour 17 (Cross), 136, 15 lbs

Softest nylon multi:

Head Perfect Power 17, 144, 15 lbs
Gamma Professional 18, 144, 15 lbs
Alpha Gut 2000 18, 146, 15 lbs

Stiffest gut:

Grand Slam Gut Grand Slam Gut 15L (uncoated), 129, 11 lbs
Babolat Tonic+ Thermogut Longevity, 119, 9 lbs
Babolat VS Touch Thermogut 15L, 118, 9 lbs

Softest gut:

Pacific Tough Gut 16L, 83, 8 lbs
Pacific Tough Gut 16, 88, 7 lbs
Pacific Classic Gut 16L , 92, 6 lbs

data
 
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P

parasailing

Legend
Has anyone experience using both Pacific and Babolat VS gut and can verify that Pacific is actually softer than Babolat VS? From the reviews on tennis warehouse, there seems to be reviews that suggest that Pacific is actually stiffer and not softer than Babolat VS.
 
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Hall of Fame
The racquets were strung at 62 lbs and were tested with a "fast" swing.
 
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C

Cruzer

Professional
parasailing said:
Has anyone experience using both Pacific and Babolat VS gut and can verify that Pacific is actually softer than Babolat VS? From the reviews on tennis warehouse, there seems to be reviews that suggest that Pacific is actually stiffer and not softer than Babolat VS.
Click to expand...

Personally I find VS is softer than Pacific Tough or Classic gut, although the difference is not huge. Both are very good gut strings however my preference is VS.
 
Centered

Centered

Hall of Fame
There are strings from 2008 that aren't listed in the 2010 tests, such as that Unique gut I posted above, and this string:

All of the three softest multis have disappeared:

Pro Kennex IQ Element Z 17 Zyex 1.21 137 14.38
Prince More Feel 16 Nylon/Softflex 1.31 138 14.69
Pro Kennex IQ Comfort 17 Polyolefin 1.27 142 14.75

Of the next three softest multis, only one is still around (Gamma):

Gamma Professional 18, Nylon/Zyex, 1.22, 144, 15.15
PowerAngle Duo Color TNT Fat Core 17 , Nylon, 1.26, 145, 15.02
Pro Kennex IQ Element 2 16, Zyex, 1.3, 145, 13.12

These are just a touch stiffer and are still around:

Alpha Gut 2000 18, Nylon, 1.21, 146, 14.49
Ashaway Dynamite 17, Zyex/Nylon, 1.24, 147, 13.72

The soft polyolefin crosses may still be around, though:

Head Intellistring/Intellitour 17 (Cross), Polyolefin, 1.28, 136, 15.14
Isospeed Platinum 16 (Cross), Polyolefin, 1.27, 138, 16.62
Head Protector 16 (Cross), Polyolefin, 1.31, 140, 15.77
Head Intellitour 16 (Cross), Polyolefin, 1.33, 143, 14.77

So, if Head were to sell that Intellistring/Intellitour cross as a full set, then it would have the softest non-gut string on the market (assuming Klip Zyex, which is untested, is stiffer).
 
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S

Sizz

New User
Interesting read. There seems to be lots of useful data there but I wonder how viable their tension loss test is. The brief description of the test procedure describes stringing a single string to 62lbs, 200 second rest, then striking it 5 times "with a force equivalent to hitting a 120mph serve". I'm curious how much force this is. I'm hoping they didn't just calculate how much force it takes to hit a ball 120mph and apply that to a single string. This would be much more force than a single string would see in the real world.

I'm disappointed they only struck the string 5 times and only recorded the overall effect. I know I have to hit more than 5 times to break a racket in. The tension loss of a string over time should look like an exponential decay plot, where the majority of the tension loss occurs during the break-in period, then flattens out where it slowly decays. The latter part, which is what most people refer to as tension stability, is the data we really need. Unfortunately, they only give 1 data point per string so we have no idea if it's during or after the break-in.

There's a lot of potential in these tests. It definitely took a lot of time and effort to test all those strings. I hope in the future they can map out the long term durability. Even 10 data points at say every 30 hits would be very useful.
 
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Hall of Fame
Someone just suggested Kevlar string to someone with tennis elbow.

The hilarity never ceases!

Unfortunately there is nothing for the WeissCannon string.
 
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Hall of Fame
elmer_fudd said:
Oops...I mean nylon monofilament =P. Thanks for the excellent link!
Click to expand...

Gamma TNT2 Tour is a wrapped multi-core multifilament string with a somewhat unusual construction. In the core, a solid high-tenacity polyamide (nylon) outer matrix surrounds six high-energy monofilaments. The outer matrix is stiffer than the individual core monofilaments. Around this composite core is a single layer wrap, which includes both monofilaments and multifilament bundles.
Click to expand...
via Racquet Sports Industry magazine
 
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Ok, it's hybrid. What a confusing naming scheme.

It has a monofilament core but multifilament outer wraps.

gamma-tnt2-17g.jpg


I switched it with Alpha Sphere 16.
 
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Centered

Centered

Hall of Fame
It's nifty, but could use some improvement.

Getting a report of all strings, for instance, yields just numbers for each string, not the names of the strings. There are some strings missing, like Dynamite 17.

The String Comparison Tool gave me the same string twice, once at "choice" and once with -2%. hmm

A good start, though, for sure.
 
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T

TW Professor

Administrator
Centered said:
It's nifty, but could use some improvement.

Getting a report of all strings, for instance, yields just numbers for each string, not the names of the strings. There are some strings missing, like Dynamite 17.

A good start, though, for sure.
Click to expand...

You get the name of the strings by clicking the display string button.
 
Centered

Centered

Hall of Fame
Centered said:
It's interesting to see that Ashaway Dynamite WB is much less stiff according to these ratings than in the RSI ratings. 109.7
Click to expand...
(accidentally hit edit instead of reply)
 
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Centered

Centered

Hall of Fame
Centered said:
It's interesting to see that Ashaway Dynamite WB is much less stiff according to these ratings than in the RSI ratings. 109.7
Click to expand...
Do you have any idea why there's such a big difference?

The RSI data gives the string 165.
 
T

TW Professor

Administrator
Centered said:
Do you have any idea why there's such a big difference?

The RSI data gives the string 165.
Click to expand...

There are several reasons.
1. First, the TWU Database String Performance Tool allows you to see the stiffness of a string under 12 different situations:
High tension (62 lbs)--fast swing
High tension--medium swing
High tension-- slow swing
Medium tension (51 lbs)--fast swing
Medium tension -- medium swing
Medium tension -- slow swing
Low tension (40 lbs) -- fast swing
Low tension -- medium swing
Low tension -- slow swing
and for most strings:
Prestrecthed high tension -- fast swing
Prestretched high tension -- medium swing
Prestretched high tension -- slow swing

The image below shows the results for Dynamite, without the prestretch results:

stringcompare6.jpg


The stiffness (and everything else) will be different depending on which of those combinations you choose as most relevant to you. The one you picked, 109.7, was for low tension and medium swing. RSI only tests at one impact profile, high tension--fast swing, and has a stiffness of 165 lb/in. For the same swing, the TWU number is 149.7. Now we are getting close. But why the difference? See number 4 below concerning test method (as well as 2 and 3).

2. Second, and related to #1, there is no such thing as THE stiffness (or THE energy return, or THE peak force, or THE anything). You are never testing the same string. It is changing every second. As tension is lost, the string is getting less stiff. The key to comparing strings is to expose them all to the exact same sequence of procedures so that they can be compared in similar circumstances. It is the relative results of one string to all others under the same circumstances that is being compared. And by extrapolation, you must assume that under a plus/minus range of typical events, the strings will keep their relative performance positions.

3. Third, and related to #2, over larger variances in swing speed and tension, any given string may (or may not) change its response profile. A string may have properties that make it relatively softer at higher impact forces than lower, or vice versa, than other strings, so much so that their relative "rankings" may flip flop from one circumstance to another. For that reason, we test the strings under the wide ranging force spectrum listed above. In that way you can choose the circumstances that are most similar to your style of play and compare the way strings behave under conditions similar to those during your play.

4. Fourth, testing method, as implied above, will make a difference, even if testing the same swing speed and tension. RSI does the following: pull tension, wait 200 secs., perform 5 impacts, take average. TWU does this: pull tension, wait 60 secs., perform 20 tension stabilization impacts (which also is taking some time), perform 1 test impact. The biggest difference will occur from the 20 stabilization hits. That will lower the tension more and the test measurement will be taken at a lower resulting tension and thus come up with a slightly lower stiffness. The stabilization hits are meant to get the strings into a more stable and "play-like" condition before measuring them. So the two test methods will be testing the string in slightly different conditions. However, for the high tension--fast speed test, the resulting string condition that is tested should be close enough so that the relative positions of strings will be very similar, even if the stiffness number is slightly different.
 
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Hall of Fame
Thanks for the info. Very interesting!

Now we need Dynamite 17, Klip Zyex, and that Bow Brand string if it still exists. :)

It's too bad the Pro Kennex IQ strings aren't available anymore.
 
rromeo

rromeo

New User
energy return %

TW Professor said:
There are several reasons.
1. First, the TWU Database String Performance Tool allows you to see the stiffness of a string under 12 different situations:
High tension (62 lbs)--fast swing
High tension--medium swing
High tension-- slow swing
Medium tension (51 lbs)--fast swing
Medium tension -- medium swing
Medium tension -- slow swing
Low tension (40 lbs) -- fast swing
Low tension -- medium swing
Low tension -- slow swing
and for most strings:
Prestrecthed high tension -- fast swing
Prestretched high tension -- medium swing
Prestretched high tension -- slow swing

The image below shows the results for Dynamite, without the prestretch results:

stringcompare6.jpg


The stiffness (and everything else) will be different depending on which of those combinations you choose as most relevant to you. The one you picked, 109.7, was for low tension and medium swing. RSI only tests at one impact profile, high tension--fast swing, and has a stiffness of 165 lb/in. For the same swing, the TWU number is 149.7. Now we are getting close. But why the difference? See number 4 below concerning test method (as well as 2 and 3).

2. Second, and related to #1, there is no such thing as THE stiffness (or THE energy return, or THE peak force, or THE anything). You are never testing the same string. It is changing every second. As tension is lost, the string is getting less stiff. The key to comparing strings is to expose them all to the exact same sequence of procedures so that they can be compared in similar circumstances. It is the relative results of one string to all others under the same circumstances that is being compared. And by extrapolation, you must assume that under a plus/minus range of typical events, the strings will keep their relative performance positions.

3. Third, and related to #2, over larger variances in swing speed and tension, any given string may (or may not) change its response profile. A string may have properties that make it relatively softer at higher impact forces than lower, or vice versa, than other strings, so much so that their relative "rankings" may flip flop from one circumstance to another. For that reason, we test the strings under the wide ranging force spectrum listed above. In that way you can choose the circumstances that are most similar to your style of play and compare the way strings behave under conditions similar to those during your play.

4. Fourth, testing method, as implied above, will make a difference, even if testing the same swing speed and tension. RSI does the following: pull tension, wait 200 secs., perform 5 impacts, take average. TWU does this: pull tension, wait 60 secs., perform 20 tension stabilization impacts (which also is taking some time), perform 1 test impact. The biggest difference will occur from the 20 stabilization hits. That will lower the tension more and the test measurement will be taken at a lower resulting tension and thus come up with a slightly lower stiffness. The stabilization hits are meant to get the strings into a more stable and "play-like" condition before measuring them. So the two test methods will be testing the string in slightly different conditions. However, for the high tension--fast speed test, the resulting string condition that is tested should be close enough so that the relative positions of strings will be very similar, even if the stiffness number is slightly different.
Click to expand...

First off, this is a fantastic tool to get objective info about strings that I haven't been able to find anywhere else. I have a couple of questions, though, that would help me in some of the string tests that I am currently doing.

With regard to swing speed, what tip speed mph or range does "slow", "medium", and "fast" correspond to?

Also is there any way to relate the energy return of a string to an actual ball speed measurement? For example if string A returns 5% more energy than string B does that mean that the rebound speed of a ball from string A will be a certain amount faster (5% ?) than that of string B in mph or m/s given the same racquet specs, impact location, and swing speed?

Thanks in advance for your assistance.
 
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Hall of Fame
I finally got a chance to get one of my racquets strung with Dynamite. I used the thicker WB. It definitely plays better than the monofilament nylon ("synthetic gut") that was in it, but I think I'll prefer the thinner Dynamite or perhaps the Dynamite Soft. I generally like thinner gauge string. For instance, I greatly prefer 17 gauge VS over the 16.

I also think I'll use a bit more tension because it's easy to launch the ball past the baseline at the fairly low tension I used. String movement was a bit more pronounced than with the nylon, but not a big issue.

It's not as soft as natural gut, but feels more powerful than NRG-2, which is the synthetic I used to choose until I found out about Dynamite. My forehand was working better for winners than with the "synthetic gut". I'm wondering when TW will stock the Dynamite Soft.
 
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