Category Archives: Technology
Wrong Planet?
Yesterday a good friend was in the World Headquarters, and as usual, our discussion turned to player training, the necessity, and the over-training of players, mainly juniors!
This training may include the wrong equipment setup, unnecessarily stiff strings, and sometimes stiff, light racquets. This may cause injuries at every level of player from recreational to professional!
My friend, by the way, is a Collegiate All-American, a professional player, and a coach!
After we discussed how to change this behavior, she said something quite interesting;
“John, you are on a different planet!”
Yikes!
So two things can happen;
- Abandon my planet
- Invite you to join our planet!
We have chosen number 2!
- to invite you to our planet!
There will be no need for interplanetary travel right now, but we do need to pick a name for our planet, so, the person presenting the best name will be the Mayor of our planet (your name here)…for a while.
We hope you will join us and make our planet a place we can all go to discover, learn, share, and understand as much as we can about tennis equipment, customization, stringing, and “best practices”.
Please use the “Leave Comment” tab below to submit your name for our new planet!
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 Radical MP 2023
You have seen the pretty pictures; now see the specs of this new Radical series!
We are starting our property review with the Head Radical MP 2023. The MP version will probably be the most popular due to the very lovely weight and “player” style head size of 98 inches!

Head Radical MP 2023
As you look at the following specifications you may notice the addition of some “numbers”, specifically “beam width”.
We have been taking this number for many years but now believe it is time to expose it to you, the readers.
Briefly, the beam height-to-width ratio contributes to in-plane stiffness which is important for consistent string bed stiffness (SBS).
Manufacturer | Head |
---|---|
Racquet Model | Head Radical MP 2023 |
Reference Tension | 55 |
String | MonoGut ZX Pro |
Machine Used | True Tension Professional |
String Bed Stiffness - RDC | 53.0 Units |
String Bed Stiffness -FlexFour | 64.9 pounds |
String Bed Stiffness - SBS | 51.8 pounds |
String Bed Stiffness - ERT | 35 Kg/Cm |
Racquet Flex, RDC | 65 - After stringing |
Racquet Flex, FlexFour | 44.5 |
Racquet - In Plane Stiffness | 379.7 lbs/Inch |
Weight, Grams | 326 |
Weight, Ounces | 11.50 |
Balance, mm | 333 |
Balance, Inch | 13.11 |
Length, Cm | 68.57 |
Length, Inch | 27.00 |
Head Width | 9.63 |
Head Length | 12.79 |
Head Area, cm2 | 623.0 |
Head Area, Sq. Inch | 96.7 |
Beam Height @ Grip, mm | 21.0 |
Beam Height @ Mid, mm | 22.5 |
Beam Height @ Tip | 20.5 |
Beam Width @ Grip, mm | 12.5 |
Beam Width @ Throat, mm | 11.5 |
Beam Width @ Mid, mm | 12.8 |
Beam Width @ Tip, mm | 12.8 |
Number of Main Strings | 16 |
Number of Cross Strings | 19 |
Ratio Cross/Mains | .634 |
Main String Grid | 7.18 |
Cross String Grid | 9.44 |
Density (% of head filled with string) | 69.6% |
Average Cross String Space | .494 |
Average Main String Space | .449 |
Dynamic Tension, Kp, ERT | 35 |
Dynamic Tension, Lbs/in | 195.76 |
First Moment, Nm | .841 |
Polar Moment | 347 |
Torsional Stability | 16 |
Swing Weight, Kg/cm2 | 331 |
Swing Weight, Ounces | 11.68 |
Swing Weight Calculated | 361.5 |
Power, RDC | 52 |
Control, RDC | 49 |
Manueverability, RDC | 66 |
Power, Calculated | 2101.4 |
Head Points | 3.15 |
Head Weight, % | 48.5% |
Center of Percussion | 21.1 |
Dwell Time, ms | 8.74 |
Efective Stiffness - lbs | 29.2 |
K, Lb/In | 169.87 |
Recoil Weight | 156.44 |
Twist Weight | 226.48 |
End Weight | 126.0 |
Tip Weight | 197.7 |
9 O'Clock | 105.1 |
3 O'Clock | 104.7 |
Butt Cap | 115.6 |
COF, Main | .416 |
COF, Cross | .388 |
Head…just when you thought it couldn’t get any better
The Head Radical has always been one of the best performance racquets available and doesn’t require much in the way of annual changes!
We think this new group is right on target! Adding Auxetic in the throat brings this series into the overall success of the Auxetic component!
We will be doing full reviews very soon, but in the meantime, take a look at these new Radicals!
The Team is the new “S” in the Radical Series! Based on our initial testing, we think this model has a trick up its sleeve!
ZUS Tennis
Never heard of them? I hadn’t either until yesterday!
ZUS is a Chicago-based company that offers several racquets with various specifications available.
A ZUS Custom Sven Goth Design came in for work, so we had a great opportunity to get all of the specifications and include them in a “racquet review”!
First, the racquet seems to be a well-made version of the Wilson Pro Staff RF, with an ever so slightly thinner modified box section beam. the geometry is very much like the Wilson Pro Staff RF, as is the weight.
This racquet has a bunch of weight at the rear end, plus a shrink sleeve to increase the grip size, so it is loaded up with weight down there, which is OK!

Rear Weight
The racquet is foamed, probably the entire tube, which may contribute a more muted feel than a non-foamed racquet. The Pro Staff RF is also foam filled.
The small oval piece is a lead or steel, weight sandwiched between the two halves of the shaft. This construction makes it impossible to remove that weight if you want to, but it is good to have it there!
Manufacturer | ZUS |
---|---|
Racquet Model | ZUS Custom Sven Goth Design |
Reference Tension | 50 |
String | Prince Tour XR 16 |
Machine Used | True Tension Professional |
String Bed Stiffness - RDC | 53.0 Units |
String Bed Stiffness -FlexFour | 59.1 pounds |
String Bed Stiffness - SBS | 50.6 pounds |
String Bed Stiffness - ERT | 35 Kg/Cm |
Racquet Flex, RDC | 63 - After stringing |
Racquet Flex, FlexFour | 41.0 |
Racquet - In Plane Stiffness | 438.0 lbs/Inch |
Weight, Grams | 354 |
Weight, Ounces | 12.49 |
Balance, mm | 316 |
Balance, Inch | 12.44 |
Length, Cm | 68.57 |
Length, Inch | 27.00 |
Head Width | 9.41 |
Head Length | 12.80 |
Head Area, cm2 | 610.1 |
Head Area, Sq. Inch | 94.6 |
Beam Height @ Grip, mm | 20.5 |
Beam Height @ Mid, mm | 20.2 |
Beam Height @ Tip | 20.6 |
Beam Width @ Grip, mm | 10.8 |
Beam Width @ Throat, mm | 10.8 |
Beam Width @ Mid, mm | 11.6 |
Beam Width @ Tip, mm | 12.4 |
Number of Main Strings | 16 |
Number of Cross Strings | 19 |
Ratio Cross/Mains | .619 |
Main String Grid | 7.25 |
Cross String Grid | 9.68 |
Density (% of head filled with string) | .742 |
Average Cross String Space | .509 |
Average Main String Space | .453 |
Dynamic Tension, Kp, ERT | 35 |
Dynamic Tension, Lbs/in | 195.76 |
First Moment, Nm | .854 |
Polar Moment | 348 |
Torsional Stability | 18 |
Swing Weight, Kg/cm2 | 330 |
Swing Weight, Ounces | 11.64 |
Swing Weight Calculated | 353.5 |
Power, RDC | 51 |
Control, RDC | 49 |
Manueverability, RDC | 67 |
Power, Calculated | 1965.9 |
Head Points | 8.46 |
Head Weight, % | 46.1% |
Center of Percussion | 20.9 |
Dwell Time, ms | 8.74 |
Efective Stiffness - lbs | 28.8 |
K, Lb/In | 169.87 |
Recoil Weight | 167.26 |
Twist Weight | 235.57 |
End Weight | 151.7 |
Tip Weight | 197.9 |
9 O'Clock | 105.5 |
3 O'Clock | 108.1 |
Butt Cap | 137.1 |
COF, Main | .382 |
COF, Cross | .306 |