Category Archives: Accuracy
Why String Bed Stiffness (SBS) matters.
String bed stiffness is a critical performance metric and therefore deserves more attention than it gets in the discussion(s) of string characteristics.
In this video, which is a little “jumpy” at first, you will see the data we collect for every racquet we do. For this discussion, we concentrate on these data:
- Reference Tension
- RDC string bed stiffness
- Flex Four-string bed stiffness
- Racquet Quest SBS (String Sense) stiffness
- Effective stiffness
- Master Tensometer string bed stiffness (kg/cm^)
Tolerance – Why and How Much?
This topic comes up frequently when clients are at Racquet Quest’s World Headquarters. But what if you are not at the World Headquarters?
Play Better Longer
For many years, we have been testing all racquets for string bed stiffness, effective stiffness, flexural stiffness, in-plane stiffness, and about any other stiffness you can imagine.
Throughout this process, we were also testing the strings for power potential, creep, string-on-string friction, and linearity.
Linearity is a significant property of string; however, it does not get the attention we believe it deserves. So, this little post will begin to change that. We will start with some images and explain what we see in them.
String Behavior
Four different string materials are represented here from left to right:
- RPM Blast
- IsoSpeed Polypropylene Composite
- Babolat VS Touch Natrual Gut
- Ashaway MonoGut ZX Polyether ether ketone (PEEK)
The entire chart is important, but the real property we are interested in for this post is “linearity”.
- Linearity is how straight the plot is from the beginning to failure.
- Failure is the vertical line associated with each string material.
A glance will show MonoGut ZX with the longest linear track, however, Babolat VS Touch is the very “straightest”, followed by IsoSpeed and RPM Blast.
OK, but why do we care? We care because when we say a string will play better longer, it is based on the linearity which is the property directly related to consistency.
Better predictability = better performance
Players perceive predictability more than raw stiffness.
A string that ages predictably plays better longer, even if it’s not the softest or most powerful.
That’s it!
Now all we need to do is quantify “better”.
I will leave that up to you.
Take a Guess?
A very good player and client came into the World Headquarters Wednesday with his three (3) Tecnifibre TF40 315’s wanting to re-string. There is nothing unusual about that except this time he wanted to discuss different strings. So we did!
The final three (3) strings under discussion were:
- Tecnifibre Razor Soft 17 (current string)
- Volkl V-Star 17
- MonoGut ZX Pro 17
The first two are considered to be polyester, however, I am not sure V-Star fits entirely in that category, and PEEK is the material with the MonoGut ZX Pro name. All of the strings are monofilament.
We learned in a previous post “a picture is worth a thousand words”, so we are including a picture to help in our guessing.
Take a Guess?
Here are some basic properties of the subject racquet that may contribute to your guess
- Weight=342
- Swing Weight=327
- RDC Flex=63
- Flex Four Flex=50.8
- Grip Size= 3
We hope you will make a guess in the “comment field” below and if you do you can use the string name or the color…we will figure it out, and thank you for you guess!
Racquet Quest, LLC
