Category Archives: Technology
Strring Bed Stiffness + Effective Stiffness
Racquet Quest lives by numbers, and these are two (2) of the most important.
This short video will, we hope, help explain why they are important and how they can be used to enhance the player’s performance, and that is “consistency”!
Racquet Quest has several different stringing machine models, and we evaluate different setups on each. It is clear that a “reference” tension across different machines will produce different string-bed stiffnesses.
Take a look at the following video and let us know if you think SBS (string bed stiffness) needs to be the new “reference tension”.
Wilson Defyer Pro 98 v1.0
Wilson Defyer Pro 98 v1
The Wilson Defyer product release is one of the most unusual and talked-about releases in a long time!
The initial prototypes were “Python”; the next iteration was “Redline”; and the newly released, and final, version is the “Defyer”.
The Defyer is available in 98 and 100 square inch head sizes. The string pattern is 16×20 with spacing that allows for a broad range of string bed stiffnesses to suit most play styles.
The head shape and geometry are familiar; however, there is some “sculpting” going on that adds something to the overall appearance.
While appearance is important, the real stuff is in the numbers, and we have those right here…
After you go through the numbers, stick around for some additional highlights that may go unnoticed.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | Defyer Pro 98 v1 |
| Reference Tension | 56 |
| String | MonoGut ZX Pro |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 47 |
| String Bed Stiffness -FlexFour | 61 |
| Strig Bed Stiffness - SBS | 51.7 |
| String Bed Stiffness - ERT | 33 |
| Racquet Flex, RDC | 65 |
| Racquet Flex, FlexFour | 51.5 |
| Racquet - In Plane Stiffness | 474.4 |
| Weight, Grams | 325 |
| Weight, Ounces | 11.46 |
| Balance, mm | 327 |
| Balance, Inch | 12.87 |
| Length, Cm | 68.7 |
| Length, Inch | 27.047 |
| Head Width | 9.80 |
| Head Length | 12.76 |
| Head Area, cm2 | 633.7 |
| Head Area, Sq. Inch | 98.2 |
| Beam Height @ Grip, mm | 22.5 |
| Beam Height @ Mid, mm | 23.8 |
| Beam Height @ Tip | 22.5 |
| Beam Width @ Grip, mm | 18 |
| Beam Width @ Throat, mm | 13.8 |
| Beam Width @ Mid, mm | 11 |
| Beam Width @ Tip, mm | 13.6 (w/Bumper Guard) |
| Number of Main Strings | 16 |
| Number of Cross Strings | 20 |
| Ratio | .614 |
| Main String Grid Inch/mm | 7.56/192.2 |
| Cross String Grid Inch/mm | 10.41/264.4 |
| Density (% of head filled with string) | .768 |
| Average Cross String Space | .520 |
| Average Main String Space | .453 |
| Dynamic Tension, Kp, ERT | 33 |
| Dynamic Tension, Lbs/in | 184.57 |
| First Moment, Nm | .819 |
| Polar Moment | 333.0 |
| Torsional Stability | 16 |
| Swing Weight, Kg/cm2 | 317 |
| Swing Weight, Ounces | 11.18 |
| Swing Weight Calculated | 347.5 |
| Power, RDC | 54 |
| Control, RDC | 44 |
| Manueverability, RDC | 74 |
| Power, Calculated | 2044.1 |
| Head Points | 5.20 |
| Head Weight, % | 47.6% |
| Center of Percussion | 20.9 |
| Dwell Time, ms | 6.83 |
| Efective Stiffness - lbs | 27.3 |
| K, Lb/In | 150.64 |
| Recoil Weight | 151.88 |
| Twist Weight | 233.42 |
| End Weight | 134.4 |
| Tip Weight | 194.4 |
| 9 O'Clock | 97.4 |
| 3 O'Clock | 94.8 |
| Butt End | 137.4 |
| COF, Main | .382 |
| COF, Cross | .315 |
Something with tennis racquets that is important to us is “serviceability”. The Defyer, like most Wilson racquets, has a nice grommet system that protects the string from “court contact” damage, and is “aerodynamic” in shape.
The grip pallet system is another matter, however, and makes grip size and shape modifications difficult, if not impossible. So, when you are making a purchasing decision, be sure you are choosing the correct grip size. This pallet system is not unique to the Defyer, but the Defyer is in the category of “customizable” racquets. Don’t plan on much grip customization!
What is “Soft”?
For many years, we have been testing string for elongation and subsequent power potential.
There is a new batch of strings that include the term “soft” in the promotional language, seemingly in an effort to mitigate the injuries associated with very stiff strings.
At some point, we can go into detail about how the soft version of a string compares to the non-soft version; however, for now, I want to reintroduce you to a post we did in 2016… almost ten (10) years ago!
Click on this link to go to that post
Thank you for reading this again. It is important “Play Harder not Hurter™”
The Consumer and SBS
Sting Bed Stiffness (SBS) could be considered alongside performance cars. In the simplest of terms, a high-performance car requires some understanding of what it is going to do; otherwise, you will end up in the trees or worse!
The same with String Bed Stiffness (SBS). If you don’t know what it is going to do, you may end up in the fence!
Racquet Quest, LLC
