Search Results for Numbers
Numbers, numbers, numbers! What do they mean?
With each of our racquet reviews a long list of numbers is included. It has been a few years since we explained what these numbers mean so here it is;
| Manufacturer | Head |
|---|---|
| Racquet Model | Head Radical MP 2023 |
| Reference Tension | 55 (what you tell the stingers to set the stringing machine). This should be replaced by String Bed Stiffness (SBS) |
| String | MonoGut ZX Pro |
| Machine Used | True Tension Professional |
| String Bed Stiffness - RDC | 53.0 Units (Babolat RDC) |
| String Bed Stiffness -FlexFour | 64.9 pounds (Flex Four) |
| String Bed Stiffness - SBS | 51.8 pounds (Racquet Quest string bed stiffness SBS Master) |
| String Bed Stiffness - ERT | 35 Kg/Cm (previously Beer's ERT1000) |
| Racquet Flex, Babolat RDC | 65 - After stringing (unstrung racquets will be slightly stiffer. Loaded from the tip) |
| Racquet Flex, FlexFour | 44.5 (Loaded from the COP) |
| Racquet - In Plane Stiffness | 379.7 lbs/Inch (stiffness across the 3 ad 9 o'clock positions of the racquet head) |
| 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 (how thick the racquet is looking at the side) |
| Beam Height @ Mid, mm | 22.5 (how thick the racquet is looking at the side) |
| Beam Height @ Tip | 20.5 (how thick the racquet is looking at the side) |
| Beam Width @ Grip, mm | 12.5 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Throat, mm | 11.5 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Mid, mm | 12.8 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Tip, mm | 12.8 (how thick the racquet is looking at the front or face view) |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio Cross/Mains | .634 ( typically the natural ratio) |
| Main String Grid | 7.18 (the distance between the two outer most main strings) |
| Cross String Grid | 9.44 (the distance between the two outer most cross strings) |
| Density (% of head filled with string) | 69.6% (how much of the head area is filled with string) |
| Average Cross String Space | .494 (how far apart the strings are). The farther apart the quicker the wear. |
| Average Main String Space | .449 (how far apart the strings are). The farther apart the quicker the wear. |
| Dynamic Tension, Kp, ERT | 35 (string bed stiffness in kilos per centimeter) |
| Dynamic Tension, Lbs/in | 195.76 (DT converted to pounds per inch) |
| First Moment, Nm | .841 (sometimes called pickup weight) |
| Polar Moment | 347 (torsional weight) |
| Torsional Stability | 16 ( resistance to twisting on off center hits) |
| Swing Weight, Kg/cm2 | 331 (the dynamic weight and the most significant property) |
| Swing Weight, Ounces | 11.68 |
| Swing Weight Calculated | 361.5 (calculated from the butt end to the tip) |
| Power, RDC | 52 (property calculated by Babolat RDC) |
| Control, RDC | 49 (property calculated by Babolat RDC) |
| Manueverability, RDC | 66 (property calculated by Babolat RDC) |
| Power, Calculated | 2101.4 (calculation based on several racquet properties) |
| Head Points | 3.15 ( a point is generally consider to be .125 inches/3.18mm) |
| Head Weight, % | 48.5% |
| Center of Percussion | 21.1 (highest COR) |
| Dwell Time, ms | 8.74 (length of time the ball is in contact with the string without a swing) |
| Efective Stiffness - lbs | 29.2 ( the calculated combined stiffness of the racquet and sting bed) |
| K, Lb/In | 169.87 (string bed stiffness in pounds/inch) |
| Recoil Weight | 156.44 (resistance to twisting about the grip) |
| Twist Weight | 226.48 (resistance to twisting about the neutral axis) |
| End Weight | 126.0 (two scale system to calculate CG) |
| Tip Weight | 197.7 (two scale system to calculate CG) |
| 9 O'Clock | 105.1 (three scale system to assure symmetry) |
| 3 O'Clock | 104.7(three scale system to assure symmetry) |
| Butt Cap | 115.6 (three scale system to assure symmetry) |
| COF, Main | .416 (the stickiness of the string bed sliding the ball with the main strings) |
| COF, Cross | .388(the stickiness of the string bed sliding the ball with the cross strings) |
Looking at the Numbers and What They Mean
The following table will shed some light on the numbers we use and hopefully shed some light on what they can mean in terms of your racquet.
| Manufacturer | Head |
|---|---|
| Racquet Model | Head Radical MP 2023 |
| Reference Tension | 55 (what you tell the stingers to set the stringing machine). This should be replaced by String Bed Stiffness (SBS) |
| String | MonoGut ZX Pro |
| Machine Used | True Tension Professional |
| String Bed Stiffness - RDC | 53.0 Units (Babolat RDC) |
| String Bed Stiffness -FlexFour | 64.9 pounds (Flex Four) |
| String Bed Stiffness - SBS | 51.8 pounds (Racquet Quest string bed stiffness SBS Master) |
| String Bed Stiffness - ERT | 35 Kg/Cm (previously Beer's ERT1000) |
| Racquet Flex, Babolat RDC | 65 - After stringing (unstrung racquets will be slightly stiffer. Loaded from the tip) |
| Racquet Flex, FlexFour | 44.5 (Loaded from the COP) |
| Racquet - In Plane Stiffness | 379.7 lbs/Inch (stiffness across the 3 ad 9 o'clock positions of the racquet head) |
| 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 (how thick the racquet is looking at the side) |
| Beam Height @ Mid, mm | 22.5 (how thick the racquet is looking at the side) |
| Beam Height @ Tip | 20.5 (how thick the racquet is looking at the side) |
| Beam Width @ Grip, mm | 12.5 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Throat, mm | 11.5 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Mid, mm | 12.8 (how thick the racquet is looking at the front or face view) |
| Beam Width @ Tip, mm | 12.8 (how thick the racquet is looking at the front or face view) |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio Cross/Mains | .634 ( typically the natural ratio) |
| Main String Grid | 7.18 (the distance between the two outer most main strings) |
| Cross String Grid | 9.44 (the distance between the two outer most cross strings) |
| Density (% of head filled with string) | 69.6% (how much of the head area is filled with string) |
| Average Cross String Space | .494 (how far apart the strings are). The farther apart the quicker the wear. |
| Average Main String Space | .449 (how far apart the strings are). The farther apart the quicker the wear. |
| Dynamic Tension, Kp, ERT | 35 (string bed stiffness in kilos per centimeter) |
| Dynamic Tension, Lbs/in | 195.76 (DT converted to pounds per inch) |
| First Moment, Nm | .841 (sometimes called pickup weight) |
| Polar Moment | 347 (torsional weight) |
| Torsional Stability | 16 ( resistance to twisting on off center hits) |
| Swing Weight, Kg/cm2 | 331 (the dynamic weight and the most significant property) |
| Swing Weight, Ounces | 11.68 |
| Swing Weight Calculated | 361.5 (calculated from the butt end to the tip) |
| Power, RDC | 52 (property calculated by Babolat RDC) |
| Control, RDC | 49 (property calculated by Babolat RDC) |
| Manueverability, RDC | 66 (property calculated by Babolat RDC) |
| Power, Calculated | 2101.4 (calculation based on several racquet properties) |
| Head Points | 3.15 ( a point is generally consider to be .125 inches/3.18mm) |
| Head Weight, % | 48.5% |
| Center of Percussion | 21.1 (highest COR) |
| Dwell Time, ms | 8.74 (length of time the ball is in contact with the string without a swing) |
| Efective Stiffness - lbs | 29.2 ( the calculated combined stiffness of the racquet and sting bed) |
| K, Lb/In | 169.87 (string bed stiffness in pounds/inch) |
| Recoil Weight | 156.44 (resistance to twisting about the grip) |
| Twist Weight | 226.48 (resistance to twisting about the neutral axis) |
| End Weight | 126.0 (two scale system to calculate CG) |
| Tip Weight | 197.7 (two scale system to calculate CG) |
| 9 O'Clock | 105.1 (three scale system to assure symmetry) |
| 3 O'Clock | 104.7(three scale system to assure symmetry) |
| Butt Cap | 115.6 (three scale system to assure symmetry) |
| COF, Main | .416 (the stickiness of the string bed sliding the ball with the main strings) |
| COF, Cross | .388(the stickiness of the string bed sliding the ball with the cross strings) |
By The Numbers
Here we go with this numbers thing, again!
Our Racquet reviews are a bunch of numbers, but what do these numbers mean to you?
We have put together this table with a brief explanation of how each number can be used by you to understand how that property can be helpful.
If you see terms such as typical or normal, ignore them! With tennis players, there is no such thing as “typical and normal”!
If you need to be convinced, take a look at a previous post!
Please let us know if there is a number that needs more clarification or a number we are missing!
| Manufacturer | Yonex | What it Means |
|---|---|---|
| Racquet Model | Yonex VCore Pro 97 HD | Racquet being reviewed. |
| Reference Tension | 55 lbs - 24.9 kg | Stringing machine tension setting. Not, necessarily, the string bed stiffness. |
| String | Ashaway MonoGut ZX Pro | String brand name and gauge (Pro being 17Gauge) |
| Machine Used | True Tension Professional | Stringing machine used. |
| ASPS, RDC | 56 | The stiffness of all the strings as a unit. Normally between 30 and 65. |
| ASPS, FlexFour | 64.5 | The stiffness of the string bed as tested on this device. |
| Racquet Flex, RDC | 57 - After stringing | 50 is low (flexible) and 70 is high (very stiff). Clash 100 is 52 on this device. As is a Head Speed model. |
| Racquet Flex, FlexFour | 50 | 35 is low (flexible) 70 is high (very stiff). Clash 100 is 26 on this device. |
| Racquet - In Plane Stiffness | 353.8 lbs/Inch | This is how stiff the racquet head is across the middle. 300 is soft and 500 is very stiff. This affects the string bed stiffness. |
| Weight, Grams | 336 | 285 is light and 360 is heavy. 315 is minimum target weight for performance. |
| Weight, Ounces | 11.85 | The racquet weight in ounces, typically used in US. |
| Balance, mm | 322 | This is the center of gravity from the butt cap. If you put the racquet on a round rod this would be how much is hanging toward the butt cap. |
| Balance, Inch | 12.68 | This is the CG in ounces for US. Points head heavy or head light is part of this. |
| Length, Cm | 68.5 | This is the total length of the racquet and is the typical standard adult length. |
| Length, Inch | 26.968 | This is length in inches for the US. |
| Head Width, Inches | 9.57 | The inside width of the hitting area. |
| Head Length, Inches | 12.54 | The inside length of the hitting area. |
| Head Area, cm2 | 625.8 | The advertised hitting area in centimeters squared. |
| Head Area, Sq. Inch | 97.0 | The advertised hitting area in inches squared. |
| Number of Main Strings | 18 | The main strings are the vertical strings when looking at a standing racquet. Typically the longest strings. |
| Number of Cross Strings | 20 | The cross strings are the horizontal strings when looking at a standing racquet. Typically shorter. |
| Ratio Cross/Mains | .687 | The natural ratio of the string pattern (calculated). |
| Main String Grid | 7.25 | The total distance between right and left main string. |
| Cross String Grid | 10.18 | The total distance between the first cross string and the last cross string. |
| Density (% of head filled with string) | .783 | |
| Average Cross String Space | .509 | The higher this number the more the string will move. This number is used to help select the best string setup. |
| Average Main String Space | .403 | The higher this number the more the string will move. This number is used to help select the best string setup. |
| Properties of a moving racquet. | ||
| Dynamic Tension, Kp, ERT | 37 | This is the stiffness of a string bed in kilograms per centimeter based on a frequency. |
| Dynamic Tension, Lbs/in | 206.94 | This is the above converted to pounds per inch. |
| First Moment, Nm | .831 | This is how heavy the racquet feels in the hand. The higher the number the heavier the racquet will feel. |
| Polar Moment | 340 | This is the resistance to rotating about the center of the racquet on, say a mimes-hit. The higher the better. |
| Torsional Stability | 16 | This is the derived stability number. The higher the better within reason. Anything below 14 would need some help. |
| Swing Weight, Kg/cm2 | 324 | This is the "inertia" of the racquet and probably the most important number in the review! The higher the number the more momentum through the ball but less manueverability. |
| Swing Weight, Ounces | 11.43 | |
| Swing Weight Calculated | 348.4 | This number will be larger than the previous swing weight because it is calculated from the very end of the racquet as if there is no one holding it. A very important number. |
| Power, RDC | 42 | Calculated by the RDC. High is 100 |
| Control, RDC | 59 | Calculated by the RDC. High is 100 |
| Manueverability, RDC | 71 | Calculated by the RDC. High is 100 |
| Power, Calculated | 1740.5 | This number is calculated based on a bunch racquet properties, Including length. |
| Head Points | 6.46 (negative = head heavy) | This number is how positive or negative the balance is. A "point" is ⅛ of an inch so this racquet is a little over ¾ of an inch head light. |
| Head Weight, % | 47.0% | Calculated based on weight distribution and length. |
| Center of Percussion | 21.0 | This is the spot on the string bed that returns a "solid" hit. |
| Dwell Time, ms | 8.50 | This is how long the ball and string are in contact with no swing. A big swing will reduce this number by about half. |
| Efective Stiffness - lbs | 28.2 | This number is calculated from the string bed stiffness and the racquet stiffness. Anything under 30 will be "soft" feeling and over 35 will be "harsh". |
| K, Lb/In | 179.5 | This is how many pounds it takes to deflect the string bed one (1) inch. |
| Recoil Weight | 160.8 | This number is the racquets resistance to rotating backward. The higher the number the better for volleys. |
| Twist Weight | 230.8 | This is the racquets resistance to twisting in your hand. The higher the better. |
| End Weight | 139.8 | This weight is used to calculate the precise balance of the racquet. |
| Tip Weight | 196.2 | This weight is used to calculate the precise balance of the racquet. |
| 9 O'Clock | 100.4 | This is the weight of that position on the racquet head and is used for precise customization. |
| 3 O'Clock | 99.6 | This is the weight of that position on the racquet head and is used for precise customization. |
| Butt Cap | 135.6 | This is the weight of that position on the racquet and is used for precise customization. |
Wilson Shift 99/315 Pro
The Wilson Shift has introduced a new movement in racquet design, and the Shift 99/315 Pro rounds out the two (2) racquet series for now!
If you read the review of the 99/300 Shift, you have a good idea about the concept: on the impact, the ball moves the head down, and before the ball can leave the strings, the head moves up!
It is like you are swinging from low to high! It sounds simple, but there is more to it than that.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | Wilson Shift 99/315 Pro |
| Reference Tension | 50 |
| String | Babolat Xalt 130 |
| Machine Used | Babolat Racquet Station |
| String Bed Stiffness - RDC | 60.0 |
| String Bed Stiffness -FlexFour | 64.6 |
| String Bed Stiffness - SBS | 45.0 |
| String Bed Stiffness - ERT | 38 kg/cm |
| Racquet Flex, RDC | 70 After Stringing |
| Racquet Flex, FlexFour | 45.0 |
| Racquet - In Plane Stiffness | 383.6 Lbs/In |
| Weight, Grams | 338 |
| Weight, Ounces | 11.92 |
| Balance, mm | 321 |
| Balance, Inch | 12.64 |
| Length, Cm | 68.6 |
| Length, Inch | 27.03 |
| Head Width | 9.79 |
| Head Length | 12.74 |
| Head Area, cm2 | 632.1 |
| Head Area, Sq. Inch | 98.0 |
| 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 |
| Beam Width @ Tip, mm | 13.0(including bumper) |
| Number of Main Strings | 18 |
| Number of Cross Strings | 20 |
| Ratio Cross/Mains | .692 |
| Main String Grid | 7.13 |
| Cross String Grid | 10.44 |
| Density (% of head filled with string) | 76.0 % |
| Average Cross String Space | .522 |
| Average Main String Space | .396 |
| Dynamic Tension, Kp, ERT MasterTensometer | 38 kg/cm |
| Dynamic Tension, Lbs/in | 212.54 |
| First Moment, Nm | .832 |
| Polar Moment | 341.0 |
| Torsional Stability | 17 |
| Swing Weight, Kg/cm2 | 324 |
| Swing Weight, Ounces | 11.43 |
| Swing Weight Calculated | 346.3 (full-length) |
| Power, RDC | 49.0 |
| Control, RDC | 51.0 |
| Manueverability, RDC | 74.0 |
| Power, Calculated | 2244.1 |
| Head Points | 6.93 |
| Head Weight, % | 46.8% |
| Center of Percussion | 21.0 |
| Dwell Time, ms | 5.94 |
| Dwell Time, Spin, ms | 8.21 |
| Efective Stiffness - lbs | 32.3 |
| K, Lb/In | 192.31 |
| Recoil Weight | 161.30 |
| Twist Weight | 242.30 |
| End Weight | 135.9 |
| Tip Weight | 193.8 |
| 9 O'Clock | 98.2 |
| 3 O'Clock | 99.0 |
| Butt Cap | 130.4 |
| COF, Main | .396 |
| COF, Cross | .319 |
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 |
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