Category Archives: Evaluation
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!
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.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | Wilson Shift 300 |
| Reference Tension | 58 |
| String | PEEK 7710 |
| Machine Used | True Tension Professional |
| String Bed Stiffness - RDC | 53.0 |
| String Bed Stiffness -FlexFour | 63.5 |
| String Bed Stiffness - SBS | 43.0 |
| String Bed Stiffness - ERT | 35 kg/cm |
| Racquet Flex, RDC | 69 After Stringing |
| Racquet Flex, FlexFour | 43.0 |
| Racquet - In Plane Stiffness | 400.0 Lbs/In |
| Weight, Grams | 330 |
| Weight, Ounces | 11.64 |
| Balance, mm | 325 |
| Balance, Inch | 12.80 |
| Length, Cm | 68.6 |
| Length, Inch | 27.03 |
| Head Width | 9.82 |
| Head Length | 12.75 |
| Head Area, cm2 | 634.0 |
| Head Area, Sq. Inch | 98.3 |
| Beam Height @ Grip, mm | 23.0 |
| Beam Height @ Mid, mm | 24.0 |
| Beam Height @ Tip | 24.0 |
| Beam Width @ Grip, mm | 12.75 |
| Beam Width @ Throat, mm | 12.8 |
| Beam Width @ Mid, mm | 11.1(PWS) |
| Beam Width @ Tip, mm | 13.0(including bumper) |
| Number of Main Strings | 16 |
| Number of Cross Strings | 20 |
| Ratio Cross/Mains | .616 |
| Main String Grid | 7.25 |
| Cross String Grid | 10.81 |
| Density (% of head filled with string) | 71.7 % |
| Average Cross String Space | .494 |
| Average Main String Space | .446 |
| Dynamic Tension, Kp, ERT MasterTensometer | 35 kg/cm |
| Dynamic Tension, Lbs/in | 195.78 |
| First Moment, Nm | .826 |
| Polar Moment | 337.0 |
| Torsional Stability | 17 |
| Swing Weight, Kg/cm2 | 320 |
| Swing Weight, Ounces | 11.29 |
| Swing Weight Calculated | 348.6 (full-length) |
| Power, RDC | 54.0 |
| Control, RDC | 48.0 |
| Manueverability, RDC | 73.9 |
| Power, Calculated | 2191.7 |
| Head Points | 5.67 |
| Head Weight, % | 47.4% |
| Center of Percussion | 20.9 |
| Dwell Time, ms | 8.74 |
| Efective Stiffness - lbs | 30.0 |
| K, Lb/In | 159.87 |
| Recoil Weight | 155.31 |
| Twist Weight | 237.78 |
| End Weight | 133.1 |
| Tip Weight | 194.6 |
| 9 O'Clock | 98.4 |
| 3 O'Clock | 100.6 |
| Butt Cap | 129.0 |
| COF, Main | .396 |
| COF, Cross | .319 |
An Inside Look at String Evaluation
In this series, we will look at the various characteristics of tennis string without the tennis racquet!
Racquet Quest evaluates every string we use plus strings submitted from other sources. These evaluations are “No Prep” and “Prep”, which simply means the Prep string has been pre-stretched in the entire length. It has not been through a tennis racquet…yet!
The following images represent a string that has not been “prepped.” After these plots are fully understood we will do the same string in the”prepped” format to see if there is a difference.
What we notice immediately is the string is very “soft” as seen in the deflection of 47.8 mm to reach 50 pounds. Also, the elasticity, the ability to recover to the original length, is fairly low.
The area under the 50-pound and 47.8 mark is the stress/strain curve that shows how the string behaves in three (3) cycles. The load and number of cycles can be changed.
The long run (linearity) from the 50-pound mark to failure is quite good and suggests consistency.
The UTS, the ultimate tensile strength, of 127.1 pounds is good for this thin string.
The following plot shows the knot strength of this string.
This plot is overlayed on the previous image so a quick comparison can be made. It is common for knot strength to be lower than un-knotted string. Knot strength is primarily important to the person tying the knot. Knots rarely fail after they are successfully tied. Pulling a knot too tight or jerking can break a knot.
This plot says to us that this string needs to be handled carefully when it comes to knots! We would expect a knot strength of at least 80 pounds for typical monofilament strings, however, if this string exhibits extraordinary play characteristics anyone can learn to tie the knots!
Based on this information we would suggest this string for a player looking for extraordinary comfort, power, and relatively short life!
Wilson Pro Staff Six One 100, v14
As you know the Wilson Pro Staff Six One franchise has been around about as long as wooden racquets have been gone! A long time!
Many racquets have come and gone. Some should not have “come” and some should not have “gone”, in my opinion.
This racquet, to me, is the epitome of the Pro Staff Six One series for a few reasons.
- The 100-square-inch head size is ideal.
- The thin 22mm beam is perfect.
- The Shiny Rust finish is the best of all Pro Staffs!
- The geometry and proportions are perfect.
- The stiffness (flex) is satisfyingly low.

Wilson shiny Rust Pro Staff Six One 100
The specifications will tell us more about the racquet, but here are some things that don’t appear on the “spec” sheet.
- This is a foam-filled racquet.
- The FORTY-FIVE layup is used in this racquet.
- The grommet barrels are large enough to allow string movement.
- The bumper guard “string valley” is very deep.
Let’s take a look at the specifications.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | Wilson Pro Staff Six One |
| Reference Tension | 55 |
| String | PEEK 7710 |
| Machine Used | True Tension Professional |
| String Bed Stiffness - RDC | 52.0 Units |
| String Bed Stiffness -FlexFour | 58.6 Pounds |
| String Bed Stiffness - SBS | 50.6 pounds |
| String Bed Stiffness - ERT | 35 Kg/Cm |
| Racquet Flex, RDC | 63 - After stringing |
| Racquet Flex, FlexFour | 50.0 |
| Racquet - In Plane Stiffness | 487.2 Lbs/Inch |
| Weight, Grams | 332 |
| Weight, Ounces | 11.71 |
| Balance, mm | 330 |
| Balance, Inch | 12.99 |
| Length, Cm | 68.6 |
| Length, Inch | 27.03 |
| Head Width | 9.87 |
| Head Length | 12.82 |
| Head Area, cm2 | 641.2 |
| Head Area, Sq. Inch | 99.4 |
| Beam Height @ Grip, mm | 22.0 |
| Beam Height @ Mid, mm | 22.0 |
| Beam Height @ Tip | 22.0 |
| Beam Width @ Grip, mm | 12.85 |
| Beam Width @ Throat, mm | 12.65 |
| Beam Width @ Mid, mm | 12.38 (PWS) |
| Beam Width @ Tip, mm | 12.27 (including bumper) |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio Cross/Mains | .648 |
| Main String Grid | 7.20 |
| Cross String Grid | 10.06 |
| Density (% of head filled with string) | 72.9% |
| Average Cross String Space | .529 |
| Average Main String Space | .450 |
| Dynamic Tension, Kp, ERT MasterTensometer | 35 |
| Dynamic Tension, Lbs/in | 195.76 |
| First Moment, Nm | .847 |
| Polar Moment | 343.0 |
| Torsional Stability | 16 |
| Swing Weight, Kg/cm2 | 327 |
| Swing Weight, Ounces | 11.53 |
| Swing Weight Calculated | 361.5 (full-length) |
| Power, RDC | 51.0 |
| Control, RDC | 50.0 |
| Manueverability, RDC | 69.0 |
| Power, Calculated | 2067.9 |
| Head Points | 4.00 |
| Head Weight, % | 48.1 % |
| Center of Percussion | 20.8 |
| Dwell Time, ms | 8.82 |
| Efective Stiffness - lbs | 28.5 |
| K, Lb/In | 166.67 |
| Recoil Weight | 153.88 |
| Twist Weight | 241.58 |
| End Weight | 131.0 |
| Tip Weight | 201.5 |
| 9 O'Clock | 100.9 |
| 3 O'Clock | 102.3 |
| Butt Cap | 128.6 |
| COF, Main | .340 |
| COF, Cross | .366 |
Head Gravity 2023 Team , MP, and Pro Comparison
Moving between several reviews to compare racquets is tiresome, for sure, and inefficient!
We don’t want you to be tired or inefficient, so we include our Three Racquet Comp Data for the new Head Gravity 2023 models!

A word about “dwell time”. To get a more accurate view of the racquet we have elimiiated the player from the “slow” dwell time. This allows us to see excatly what happens when the ball is “dropped” on the string bed without any external force (your swing)!



Racquet Quest, LLC


