Category Archives: String Bed Stiffness

Compare Wilson Shift 99/300 to Shift 99/315

Comparisons are fun and can be informative as one of the steps in selecting a tennis racquet that is right for you!

If you have read the individual reviews of these two (2) racquets you may wonder about some of the numbers.

This comparison table makes it easy to see the properties.

  • You will notice very little difference in these racquets’ overall weight and swing weight. Typically tolerances will be in the plus/minus 7-gram range.
    What does that mean?
    For example:
    • A 300-gram racquet can weigh from 293 to 307 grams.
    • A 315-gram racquet can weigh from 308 to 322 grams.
      • Different model racquets can be the same weight. 
      • Same-model racquets can be an ounce different in weight.
This much variation is very rare!

So, when multiple racquets are received at the World Headquarters they are characterized to match similar racquets within a model.

A Players Perspective

We are really happy to have Jason Harne join us to review and add his comments on tennis racquets and tennis strings!

I think you will agree that Jason will be a great addition to based on the following tennis bio:

Jason Harne – Tennis

  • Pro tennis – futures tournaments and satellites
  • Stirling University, Scotland. One of the first players to be awarded the British Universities Tennis Bursary Colors Award (equivalent to All-American)
  • International home nations tournament, representing Scotland, player of the tournament award.
  • England county cup, division one, representing Yorkshire County.
  • Spain and UK, national league tennis
  • High Point University, Big South Conference, 22-2 record.
  • U21 guardian direct British futures, national champion, and fastest UK serve.
  • Teaching pro, UK and Spain, high-performance players

This is very impressive but the most important component for us, and you, is Jason’s incredible interest in new things!  Jason is willing to try, and honestly comment on, any performance tennis equipment.

Jason will be commenting on the new Wilson Shift series later this week.

Please leave a comment or question for Jason.


Wilson Shift 99/300

After the success of the Wilson Labs version of the Shift technology, Wilson decided to make a retail version. We have received the retail version of the unique racquets and certainly want to share!

Just looking at the racquet, you may ask, “What is unique about it?” Even though the term AI is overused, in this case, it was just used! Some of the concepts of the designers were fed to AI, and it went to work!

Wilson Shift 300

We don’t know the details of the AI prompts, but we do know the very wide throat will accommodate the in-plane flexure of the shaft, which lets the head move downward upon impact and then move back while the ball is in contact with the string, therefore, contributing to “spin.”

This 99-square-inch racquet comes in two (2) versions, the 300-gram and 315-gram “Pro,” with an 18×20 string pattern.

We can feel some flex in the shaft; however, the real test is hitting with this concept, so come in and try the demo.  In the meantime, take a look at the numbers.

After the numbers, be sure to watch the Wilson video of the Shift 99/300!
Racquet ModelWilson Shift 300
Reference Tension58
PEEK 7710
Machine UsedTrue Tension Professional
String Bed Stiffness - RDC53.0
String Bed Stiffness -FlexFour63.5
String Bed Stiffness - SBS43.0
String Bed Stiffness - ERT35 kg/cm
Racquet Flex, RDC69 After Stringing
Racquet Flex, FlexFour43.0
Racquet - In Plane Stiffness400.0 Lbs/In
Weight, Grams330
Weight, Ounces11.64
Balance, mm325
Balance, Inch12.80
Length, Cm68.6
Length, Inch27.03
Head Width9.82
Head Length12.75
Head Area, cm2634.0
Head Area, Sq. Inch98.3
Beam Height @ Grip, mm23.0
Beam Height @ Mid, mm24.0
Beam Height @ Tip24.0
Beam Width @ Grip, mm12.75
Beam Width @ Throat, mm12.8
Beam Width @ Mid, mm11.1(PWS)
Beam Width @ Tip, mm13.0(including bumper)
Number of Main Strings16
Number of Cross Strings20
Ratio Cross/Mains.616
Main String Grid7.25
Cross String Grid10.81
Density (% of head filled with string)71.7 %
Average Cross String Space.494
Average Main String Space.446
Dynamic Tension, Kp, ERT MasterTensometer35 kg/cm
Dynamic Tension, Lbs/in195.78
First Moment, Nm.826
Polar Moment337.0
Torsional Stability17
Swing Weight, Kg/cm2320
Swing Weight, Ounces11.29
Swing Weight Calculated348.6 (full-length)
Power, RDC54.0
Control, RDC48.0
Manueverability, RDC73.9
Power, Calculated 2191.7
Head Points5.67
Head Weight, %47.4%
Center of Percussion20.9
Dwell Time, ms8.74
Efective Stiffness - lbs30.0
K, Lb/In159.87
Recoil Weight155.31
Twist Weight237.78
End Weight 133.1
Tip Weight 194.6
9 O'Clock98.4
3 O'Clock100.6
Butt Cap129.0
COF, Main.396
COF, Cross.319

Stop by the World Headquarters of Racquet Quest, LLC,  pick up a demo, and experience this for yourself!