Category Archives: Natural Gut String
String. What is important?
The essential function of string in your tennis racquet is to return energy to the ball as it collides with the racquet. It is evident that if there is no string or a broken one, the racquet can not do what it is intended to do, and your shot is going nowhere or worse, everywhere!
There are about thirty (30) string brands, and each brand has about ten (10) different models, and maybe three (3) different colors, so there are nine hundred (900) possible selections! Nine hundred is way too many strings!
You and we need to consolidate string data so we can make the right decision for you, your playing style, and your physical capabilities.
We test every string for elongation, creep, (stability), with a little bit of elasticity data observed. This testing returns our exclusive Power Potential© for each string, and that is the basis of our decision-making process. Naturally, the higher the elongation, the more power the string will return to the ball, and conversely, the lower the power potential, the less power that “can” be generated. You can observe this fundamental by dropping a tennis ball on a concrete floor and then on a strung tennis racquet from the same drop height and see which one bounces the highest.
I use “can” because power, to a great extent, comes from how hard you swing the racquet, which, of course, brings the prospect of overdoing it and subsequent injury! A low power string demands a more powerful swing that involves the entire arm, hips, and legs.
Low power, in the form of a stiff string, has been associated with control, therefore, the increased use of stiff strings. However, with stiffness comes another downside, and that is stability. Stiff strings typically lose tension quickly and need to be changed frequently. So here is the real problem; the string may not be broken, but it is not playing well at all. There is a difference between durability and performance! If your goal is long term performance, a stiff string is not the answer.
What, then, is the answer?
Choose a string with an elongation of 10% or higher! Oh, great! You say. How am I going to know that!
Well, beginning January 1, 2020, I will be posting the power potential of every string we have tested over the years! There are over 500 items on the current list sorted by brand. The color coding is RED if 5% or less, GREEN if 10% or higher, and BLUE for everything else. Note, however, that natural gut is included in this data and will probably not reach the 10% Power Potential© threshold, but is still the best performance string available. This is due to the dynamic properties of the natural fibers, so, until there is a separate classification gut will be included as is.
A previous post, “What is Soft?” goes into graphical detail.
As new strings are added, some older ones may be deleted because they are no longer manufactured. However, some very old ones may remain due to their “legacy” status. This chart is a preliminary format but will get us map toward the right decision!
Click here to see all the current power potential data.
Dr. Goodman visits the World Headquarters!
We were thrilled to have Dr. Brad Goodman visit the World Headquarters to produce a session for his Doc-Talk-Live program!
Dr. Goodman is a tennis player who wants to know more about equipment in an effort to protect his body and beat his opponents. You can catch this episode here: Doc Talk Live
In addition to the session Dr, Goodman was given the opportunity to “stretch” both a very stiff string and a very “stretchy” string, something that he, and many others, have not done. Needless to say he was amazed at the difference.
Dr, Goodman’s visit was a great opportunity to have a real conversation about tennis equipment. Please let me have your comments!
Wilson Clash 100
Once in a while words “fit”! Clash fits this new Wilson racquet because it disrupts the trend of “everything stiff”. Luckily this trend is dying and Wilson has, in my view, done a masterful job of expediting that demise with this concept.

Not only does this racquet look good it just feels good in the hand. It is light, maybe too light, but the brain detects something different about this racquet. We all know racquets are all about “the brain”!
In this review you may notice the addition of a couple of specifications. One is “Racquet – In Plane Stiffness”. This is the racquets resistance to”squeezing the sides together. The higher the number the more resistant (stiffer) the racquet is. Another addition to the review is the three (3) weights taken at the sides of the head and at the very bottom (butt cap) of the racquet. This very helpful when matching or customizing a racquet. so I thought we would include it.
Before this racquet is strung it has a noticeable “softness” which is expected given the 52 stiffness (Wilson is not using the defacto device, RDC, for their stiffness rating). However, after stringing, the racquet takes on a different “feel”. It is like the string is pulling all the material components together! I intend to hit with this racquet tomorrow so as right now I have no idea how it will feel.
To get the maximum from this racquet our demo is strung with Luxilon Natural Gut, 125 and the new Wilson Sensation Plus multi-filament with a “wear” wrap. This should be a great setup, so if you want to hit with the latest technology this is it!
For each racquet we do an “Accuracy Index”. This tells us how accurately the ball will come off the string bed when hit at different locations on the string bed. This racquet has an index of 97, which is very good, in the areas of the string bed that show the most failure (breakage). The overall string bed index of 94 is quite good and tells us that the string bed should produce as much accuracy as the players skill allows!
Take look at the following specifications to see if you agree with the player evaluations you may have read.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | Clash 100 |
| Reference Tension | 58 lbs - 26.3 kg |
| String | Luxilon 125 Gut =M Wilson Sensation Plus =X |
| Machine Used | True Tension Professional |
| ASPS, RDC | 56 |
| ASPS, FlexFour | 61.5 |
| Racquet Flex, RDC | 51 - After stringing |
| Racquet Flex, FlexFour | 27 |
| Racquet - In Plane Stiffness | 317 lbs/Inch |
| Weight, Grams | 309 |
| Weight, Ounces | 10.90 |
| Balance, mm | 322 |
| Balance, Inch | 12.68 |
| Length, Cm | 68.5 |
| Length, Inch | 27.0 |
| Head Width | 9.92 |
| Head Length | 12.85 |
| Head Area, cm2 | 646.0 |
| Head Area, Sq. Inch | 100.1 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio Cross/Mains | .650 |
| Main String Grid | 7.50 |
| Cross String Grid | 10.37 |
| Density (% of head filled with string) | .779 |
| Average Cross String Space | .547 |
| Average Main String Space | .469 |
| Dynamic Tension, Kp, ERT | 37 |
| Dynamic Tension, Lbs/in | 206.94 |
| First Moment, Nm | .764 |
| Polar Moment | 321 |
| Torsional Stability | 15 |
| Swing Weight, Kg/cm2 | 306 |
| Swing Weight, Ounces | 10.79 |
| Swing Weight Calculated | 320.4 |
| Power, RDC | 34 |
| Control, RDC | 70 |
| Manueverability, RDC | 83 |
| Power, Calculated | 1562.7 |
| Head Points | 6.46 |
| Head Weight, % | 47.0% |
| Center of Percussion | 21.5 |
| Dwell Time, ms | 8.50 |
| Efective Stiffness - lbs | 26.7 |
| K, Lb/In | 179.49 |
| Recoil Weight | 155.9 |
| Twist Weight | 227.1 |
| End Weight | 126.8 |
| Tip Weight | 181.9 |
| 9 O'Clock | 94.0 |
| 3 O'Clock | 93.9 |
| Butt Cap | 119.9 |
What is Elongation?
In dictionary terms it is:
“the amount of extension of an object under stress.”
In tennis terms, it means the same thing when talking about tennis racquet strings.
How much does a string stretch under the reference tension load or otherwise stretched (impact)? The proliferation of wrist, arm and shoulder injury has brought attention to the property of “stiffness.” The problem is that your stiffness may be different than my stiffness, so there needs to be an “index” associated with each string, in my opinion. I have that data on over 500 tennis strings, but that is just me.
The images show the results of high elongation (left) and low elongation (right) string upon breaking.
Several years ago a player asked me “where is the string that is missing?” Well, it is not missing. The ends you see should be connected!
If the string has little elongation when it breaks there is nothing “pulling” it apart like the high elongation string. So each time you hit the ball, the string either elongates a bunch or it doesn’t.
In the case of the high elongation string, on the left, it absorbs a good portion of the “shock” associated with a hard hit, whereas the low elongation string, on the right, lets your body do the absorbing to a great extent.
So, it is reasonable to use very low reference tensions for low elongation string (35 to 45 pounds; 16 to 20.5 Kg) and higher tensions (45 to 60 pounds; 20.5 to 27.2 Kg) for high elongation strings.
You may ask, “how do I know how stiff a string is?” If you see the word “polyester or co-polyester” it is likely that string wil be stiff compared to natural gut, most nylon based multi-filament construction, and PEEK (Zyex) material. In my opinion, there is no “bad” string just “bad” applications. If in doubt…ask!
Racquet Quest, LLC


