Category Archives: elbow
It is raining today and it felt like a good time to talk about “string bed stiffness”…so let’s go!
This quick video will make a plea to you tennis players to demand more from your racquet technician so you are getting the most from your equipment.
Thank you for watching!
OK, here’s the deal. I have written about this several times and each time I decided that it was a waste of time, so it goes back into a file somewhere!
The time is now that we really need to understand more about stringing as a consumer and what we can do as racquet technicians to make the life of a player better, more fun, and safer.
This a quick story to set the premise of the rest.
Several weeks ago I received a freshly strung (24 hours) racquet to perhaps make a few modifications to the racquet. The racquet was strung by the player, a very good junior with a high ranking. The racquet was 18×20 with a full bed of polyester at 53 pounds. When I asked why the response was “I have always done it this way”. Fair enough!
The string bed stiffness (SBS) using the Beer’s ERT300 was 23, the SBS using the Babolat RDC was 29, and the SBS using the FlexFour was 50. If you are familiar with these data, you know the numbers are quite low.
The racquet had only one mis-weave and one crossover, but it was severely distorted, i.e., very wide.
For a quick comparison, a properly strung racquet would have numbers like 36, 58, and 67 respectively.
So, the “softness” of the string bed when improperly strung was something that may not transmit as much shock to the body as a racquet that was properly strung at the requested 53 pounds and has a higher SBS!
Therefore a poor stringing may save the life of polyester based string! It may not be good for performance or racquet integrity but it seems that very few players care!
So what do we do?
For years I have been advocating for the use of a finished SBS instead of a “reference tension”. Why? Because each stringer and stringing machine probably produce a different result.
If a player comes to us and requests an SBS of 37 (Beers ERT300 for example), we can adjust the stringing machine to produce that SBS number. Our machines may be set at 40 to achieve the requested 37, and another shop may have to set their machine to something different. The object is to arrive at the finished SBS, and it is up to the racquet technician to be able to do that! The result will be a better performing racquet that will last longer.
If you read the Wilson Clash 100 review there is not much to say about the Wilson Clash Tour in terms of graphics because it is exactly the same!
So we can go directly to the differences between the two models. The Tour does have the “word” tour on the racquet but little else in terms of racquet specifications and that is by design.
Typically a racquet will have some little tiny descriptions such as weight, head size, string pattern, etc. but these racquets have none of that. Wilson, with this racquet, wants the player to make all the decisions based on “feel, control, and power” and not be influenced by descriptors. As you might expect this model is a little heavier overall and in swing weight thus the “Tour” designation.
Our Wilson Clash and Clash Tour demo racquets are strung with Luxilon Natural Gut as the main string and Wilson Sensation Plus as the cross string. This combination should maximize the performance of the racquet.
Before we get to the specifications of the Tour model there is another slightly unusual design feature. The grip pallet is not molded onto the frame but is formed by the carbon fiber. This manufacturing technique does not allow for easy (seriously not easy) grip size and shape customization so be certain you get the grip size you need.
Take a look at the following data to see if you think this new concept is worth a try. Based on the feedback we are getting I would say yes, definatley!
|Racquet Model||Clash Tour|
|Reference Tension||58 lbs - 26.3 kg|
|String||Luxilon 125 Gut =M
Wilson Sensation Plus =X
|Machine Used||True Tension Professional|
|Racquet Flex, RDC||47 - After stringing|
|Racquet Flex, FlexFour||25|
|Racquet - In Plane Stiffness||317 lbs/Inch|
|Head Area, cm2||647.3|
|Head Area, Sq. Inch||100.3|
|Number of Main Strings||16|
|Number of Cross Strings||19|
|Main String Grid||7.68|
|Cross String Grid||10.44|
|Density (% of head filled with string)||.799|
|Average Cross String Space||.549|
|Average Main String Space||.480|
|Dynamic Tension, Kp, ERT||35|
|Dynamic Tension, Lbs/in||195.76|
|First Moment, Nm||.822|
|Swing Weight, Kg/cm2||329|
|Swing Weight, Ounces||11.6|
|Swing Weight Calculated||341.8|
|Head Weight, %||46.4|
|Center of Percussion||21.7|
|Dwell Time, ms||8.91|
|Efective Stiffness - lbs||24.5|
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!
If you have been around Racquet Quest for a while, you know we talk a lot about Ashaway MonoGut ZX and ZX Pro, with ZX Pro being the 17 gauge version. During this post when I use MonoGut ZX it will include the ZX Pro Version, to save pixels!
A few questions need to be answered before we begin:
1. Do you get paid to talk about Ashaway MonoGut ZX?………. No
2. Do you get Ashaway MonoGut ZX free?………. No
3. Do get to spend the summer at a lavish resort in Ashaway R.I. ………. No
4. Why do you do it, then?
The short answer is MonoGut ZX works in so many applications that it is impossible not to talk about it whenever talking about tennis racquet string, arm issues, durability, and performance!
The first thing we need to know about MonoGut ZX is that is not polyester. It is Polyetheretherketone, or PEEK, for short. MonoGut ZX can look exactly like many common polyester strings due to the monofilament format. Monofilament means it is one strand of material and is typically very smooth and shiny.
The appearance is where the similarities end. Without going into a lot of detail, the stiffness of the base material dictates the stiffness of the string, especially in monofilament formats. Every string we get is tested for “stiffness” and entered into our database. This stiffness is converted to Power Potential using proprietary software. Power Potential is easy to understand…the higher the number, the more powerful the string is.
To get to the meat of this topic, we need to know the relative values of these materials.
MonoGut ZX has a power potential of 14.62
Babolat RPM Blast has a power potential of 4.29
LaserFibre Silverline 2 has a power potential of 4.59
Luxilon ALU Power has a power potential of 4.42
Luxilon ALU Power Soft has a power potential of 5.72
There are hundreds of polyester based string, but this gives you some idea as to where they stack up vis-a-vis MonoGut ZX.
Why does this matter? Strings with very low elongation (power potential) get stiffer the harder the ball is hit! So what? So, if you have low power potential, you need to swing harder to get the ball to go as far as it needs to go especially if you are trying to hit with huge topspin.
MonoGut ZX is suited to many playing styles, racquets, and string patterns. That is why so many really good players are currently using it and winning with it. That is why it is important that we continue to talk about MonoGut ZX!
Maybe it is time to try MonoGut ZX yourself.