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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!

ManufacturerYonexWhat it Means
Racquet ModelYonex VCore Pro 97 HDRacquet being reviewed.
Reference Tension55 lbs - 24.9 kgStringing machine tension setting. Not, necessarily, the string bed stiffness.
String
Ashaway MonoGut ZX ProString brand name and gauge (Pro being 17Gauge)
Machine UsedTrue Tension ProfessionalStringing machine used.
Static
ASPS, RDC56The stiffness of all the strings as a unit. Normally between 30 and 65.
ASPS, FlexFour64.5The stiffness of the string bed as tested on this device.
Racquet Flex, RDC57 - After stringing50 is low (flexible) and 70 is high (very stiff). Clash 100 is 52 on this device. As is a Head Speed model.
Racquet Flex, FlexFour5035 is low (flexible) 70 is high (very stiff). Clash 100 is 26 on this device.
Racquet - In Plane Stiffness353.8 lbs/InchThis 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, Grams336285 is light and 360 is heavy.
315 is minimum target weight for performance.
Weight, Ounces11.85

The racquet weight in ounces, typically used in US.
Balance, mm322This 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, Inch12.68This is the CG in ounces for US. Points head heavy or head light is part of this.
Length, Cm68.5This is the total length of the racquet and is the typical standard adult length.
Length, Inch26.968This is length in inches for the US.
Head Width, Inches9.57The inside width of the hitting area.
Head Length, Inches 12.54The inside length of the hitting area.
Head Area, cm2625.8The advertised hitting area in centimeters squared.
Head Area, Sq. Inch97.0The advertised hitting area in inches squared.
Number of Main Strings18The main strings are the vertical strings when looking at a standing racquet. Typically the longest strings.
Number of Cross Strings20The cross strings are the horizontal strings when looking at a standing
racquet. Typically shorter.
Ratio Cross/Mains.687The natural ratio of the string pattern (calculated).
Main String Grid7.25The total distance between right and left main string.
Cross String Grid10.18
The total distance between the first cross string and the last cross string.
Density (% of head filled with string).783
Average Cross String Space.509The higher this number the more the string will move. This number is used to help select the best string setup.
Average Main String Space.403The higher this number the more the string will move. This number is used to help select the best string setup.
Dynamic
Properties of a moving racquet.
Dynamic Tension, Kp, ERT37This is the stiffness of a string bed in kilograms per centimeter based on a frequency.
Dynamic Tension, Lbs/in206.94This is the above converted to pounds per inch.
First Moment, Nm.831This is how heavy the racquet feels in the hand. The higher the number the heavier the racquet will feel.
Polar Moment340This is the resistance to rotating about the center of the racquet on, say a mimes-hit. The higher the better.
Torsional Stability16This is the derived stability number. The higher the better within reason. Anything below 14 would need some help.
Swing Weight, Kg/cm2324This 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, Ounces11.43
Swing Weight Calculated348.4This 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, RDC42
Control, RDC59
Manueverability, RDC71
Power, Calculated 1740.5This number is calculated based on racquet properties.
Head Points6.46 (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%
Center of Percussion21.0This is the spot on the string bed that returns a solid hit.
Dwell Time, ms8.50This 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 - lbs28.2This 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/In179.5
Recoil Weight160.8This number is the racquets resistance to rotating backward. The higher the number the better for volleys.
Twist Weight230.8This is the racquets resistance to twisting in your hand. The higher the better.
End Weight 139.8This weight is used to calculate the precise balance of the racquet.
Tip Weight 196.2This weight is used to calculate the precise balance of the racquet.
9 O'Clock100.4
This is the weight of that position on the racquet head and is used for precise customization.
3 O'Clock99.6This is the weight of that position on the racquet head and is used for precise customization.
Butt Cap135.6This is the weight of that position on the racquet and is used for precise customization.

 

 

Head Graphene 360+ Prestige Mid

The Head Prestige Mid is, in my view, the quintessential Prestige! This Prestige is the tennis racquet you would buy even if you don’t play tennis! It would sit right next to your Porsche 550 that you don’t drive much, but both make you feel really good!

The latest edition of the Prestige Mid is the Graphene 360+ Prestige Mid, and it carries on the iconic tradition of all previous models and looks better doing it, in my opinion.

In left image, you can see the overall color scheme of all of the new Prestige series, but you can’t see the detail of the “cap system” that is different than the other three (3) Prestige models.

The lower image shows the transition location.  But why?

Mid Cap System Transition

 

 

 

I think it is just a matter of weight. The cap system on the Mid stops halfway down the head instead of all around as on other models.

This slight reduction in weight allows for more customization options and this is a very customizable racquet.
So, if you are interested in an “iconic” racquet to place next to your 550, this is the one!

What could be better than arriving at the courts in your 550 and pull out your Prestige Mid racquet!

Game, Set, Match!

ManufacturerHead
Racquet ModelHead Graphene 360+ Prestige Mid
Reference Tension55 lbs - 24.9 kg
String
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC57
ASPS, FlexFour72.0
Racquet Flex, RDC63 - After stringing
Racquet Flex, FlexFour36
Weight, Grams344
Weight, Ounces12.13
Balance, mm317
Balance, Inch12.48
Length, Cm68.5
Length, Inch26.97
Head Width9.25
Head Length12.67
Head Area, cm2593.4
Head Area, Sq. Inch92.0
Beam Width, mm, Shaft, Center, Tip20, 20, 20
In Plane Stiffness, Pounds/In428.6 Lbs/In.
In Plane Stiffness, Kg/cm 194.4 Kg/cm
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.615
Main String Grid6.87
Cross String Grid8.88
Density (% of head filled with string).663
Average Cross String Space.467
Average Main String Space.429
Dynamic
Dynamic Tension, Kp, ERT37
Dynamic Tension, Lbs/in206.9
First Moment, Nm.834
Polar Moment341
Torsional Stability15
Swing Weight, Kg/cm2326
Swing Weight, Ounces11.50
Swing Weight Calculated345.7
Power, RDC47
Control, RDC53
Manueverability, RDC69
Power, Calculated 1888.9
Head Points8.03 (negative = head heavy)
Head Weight, %46.3%
Center of Percussion21.1
Dwell Time, ms, No Swing8.43
Efective Stiffness - lbs29.9
K, Lb/In (SBS) RDC182.69
Recoil Weight166.4
Twist Weight221.8
End Weight 146.7
Tip Weight 197.3
9 O'Clock104.6
3 O'Clock102.8
Butt Cap134.6

Head Graphene 360+ Prestige Pro

So, what’s in a name?  In the case of the name “Pro” it is weight!  Right out of the box this racquet is ready to go with a wonderful weight and swing weight that you will see in the specifications.

The Prestige Pro is the “different” Prestige in the series with a more sculpted geometry.  This is most noticeable in the shaft right above the grip with tapers and contours all the way to the throat.  The head geometry is more elliptical in cross section than the flat section used in other Prestige racquets.

As you look at other Prestige racquets the difference in the cross section is noticable.  The Tour for example has a “flat” beam cross section and the shaft right above the grip is also a “flat” cross section with little very little “sculpting

The Prestige Pro is a racquet anyone can use with a nice 16 x 19 string pattern and reasonable stiffness.

This is a legitimate 95 square inch racquet with a 16 x 19 string pattern that suits most players.  The full Prestige “cap system” adds a nice measure of stability along with swing weight that gets this racquet into the “power and control” category.

 

ManufacturerHead
Racquet ModelHead Graphene 360+ Prestige Pro
Reference Tension55 lbs - 24.9 kg
String
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC52
ASPS, FlexFour65.2
Racquet Flex, RDC62 - After stringing
Racquet Flex, FlexFour44
Weight, Grams338
Weight, Ounces11.92
Balance, mm327
Balance, Inch12.87
Length, Cm68.6
Length, Inch27.008
Head Width9.39
Head Length12.85
Head Area, cm2611.0
Head Area, Sq. Inch94.7
Beam Width, mm, Shaft, Center, Tip22, 22, 22
In Plane Stiffness, Pounds/In329.7 Lbs/In.
In Plane Stiffness, Kg/cm 149.5 Kg/cm
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.615
Main String Grid7.06
Cross String Grid9.12
Density (% of head filled with string).699
Average Cross String Space.494
Average Main String Space.441
Dynamic
Dynamic Tension, Kp, ERT35
Dynamic Tension, Lbs/in195.7
First Moment, Nm.852
Polar Moment350
Torsional Stability17
Swing Weight, Kg/cm2333
Swing Weight, Ounces11.75
Swing Weight Calculated361.4
Power, RDC51
Control, RDC50
Manueverability, RDC65
Power, Calculated 1955.2
Head Points4.88 (negative = head heavy)
Head Weight, %47.7%
Center of Percussion21.0
Dwell Time, ms, No Swing8.82
Efective Stiffness - lbs28.3
K, Lb/In (SBS) RDC166.7
Recoil Weight161.3
Twist Weight224.1
End Weight 136.9
Tip Weight 202.1
9 O'Clock104.4
3 O'Clock104.3
Butt Cap129.0

Head Graphene 360+ Prestige Tour

When we do the testing and “number taking” for our demo racquets, we try to think as the consumer may think and include comments that may help the consumer make the best decision.

We do not want to make these posts so dull that you go to sleep, but data is essential, so we are going to include it…so stay awake!

Data is particularly relevant to the Prestige Series from Head.

This review is for the Prestige Tour, and it points to the differences between Prestige racquets that may go unnoticed or misunderstood.

The Prestige Tour is a 99 (645 cm²)square inch racquet with an 18 x 19 string pattern. If you have read the post on the Prestige MP, you may wonder, what’s the difference?

You may notice that the Prestige Tour has one (1) fewer cross string. Not a big deal. You may see that the Prestige Tour has one (1) square inch larger head size. Also, not a big deal. What you may not notice is the Prestige Tour has an in-plane stiffness of 400, and the Prestige MP has an in-plane stiffness of 359. That is a big deal! Even with a bigger head and fewer strings, the Prestige Tour has a higher string bed stiffness than the Prestige MP. The higher the in-plane stiffness, the less the racquet will “bend” during impact.

The Prestige Tour is more stiff overall (62 v 58) than the Prestige MP, and the 21.5mm beam contributes to that stiffness.

So, take a look at the numbers for this racquet to see if you can find other exciting differences!

 

 

 

ManufacturerHead
Racquet ModelHead Graphene 360+ Prestige Tour
Reference Tension55 lbs - 24.9 kg
String
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC55
ASPS, FlexFour71
Racquet Flex, RDC62 - After stringing
Racquet Flex, FlexFour49
Weight, Grams325
Weight, Ounces11.46

Balance, mm327
Balance, Inch12.87
Length, Cm68.6
Length, Inch27.008
Head Width9.56
Head Length13.12
Head Area, cm2635.3
Head Area, Sq. Inch98.5
Beam Width, mm, Shaft, Center, Tip21.5, 21.5, 21.5
In Plane Stiffness, Pounds/In400.0 Lbs/In.
In Plane Stiffness, Kg/cm181.4 Kg/cm
Number of Main Strings18
Number of Cross Strings19
Ratio Cross/Mains.690
Main String Grid7.81
Cross String Grid10.00
Density (% of head filled with string).724
Average Cross String Space.526
Average Main String Space.396
Dynamic
Dynamic Tension, Kp, ERT35
Dynamic Tension, Lbs/in195.7
First Moment, Nm.819
Polar Moment334
Torsional Stability18
Swing Weight, Kg/cm2316
Swing Weight, Ounces11.15
Swing Weight Calculated347.5
Power, RDC46
Control, RDC55
Manueverability, RDC76
Power, Calculated 1929.2
Head Points4.88 (negative = head heavy)
Head Weight, %47.7%
Center of Percussion20.8
Dwell Time, ms, No Swing8.58
Efective Stiffness - lbs29.1
K, Lb/In (SBS) RDC176.3
Recoil Weight150.9
Twist Weight222.7
End Weight 131.7
Tip Weight 195.3
9 O'Clock100.7
3 O'Clock101.4
Butt Cap124.0

Head Graphene 360+ Prestige MP

We are finally getting the time to work on these marvelous new racquets from Head! In this case, it is the Head Graphene 360+ Prestige MP.

The Prestige is a fascinating series for Head, but I think it is often overlooked when considering a new racquet purchase. I believe the “performance” category excludes a lot of players that could very well use this racquet if it is appropriately set up. Secondly, I think players have the mistaken feeling that the Prestige series is too stiff!

I believe you will see by the following specifications that neither are necessarily true!

The Prestige series is, in my opinion, the best looking new racquet in a long time. However, in a performance racquet, what does “looks” have to do with it? In my opinion, a lot!

This racquet is the “true” 98 square inch (630 cm²) head size with an 18 x 20 string pattern and, of course, the excellent “cap system” that contributes to the performance of this racquet. You will see in the specifications that the swing weight is on the “light” side, allowing for customization to suit any player.

Head is now including a CPI, “Control Power Index,” and this racquet ranks as a CPI 200 compared to the Prestige Pro at CPI 300. The difference is a function of the tight string pattern and flex. The thin 20mm beam throughout contributes to the nice flex of RDC 58 after stringing.

A lower CPI indicates to us that the racquet will do no more than you ask of it! If you want the ball to go fast you swing harder! The racquet will not force to to “fear” your stroke!

If you are considering an 18 x 20 string pattern this racquet should be right at the top of the list.

Our COF numbers are quite good which indicate a positive contribution to “spin” considering the tight string pattern.

 

ManufacturerHead
Racquet ModelHead Graphene 360+ Prestige MP
Reference Tension55 lbs - 24.9 kg
String
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC58
ASPS, FlexFour67
Racquet Flex, RDC58 - After stringing
Racquet Flex, FlexFour39
Weight, Grams337
Weight, Ounces11.89

Balance, mm313
Balance, Inch12.32
Length, Cm68.6
Length, Inch27.008
Head Width9.47
Head Length13.05
Head Area, cm2625.9
Head Area, Sq. Inch97
Beam Width, mm, Shaft, Center, Tip20, 20, 20
In Plane Stiffness, Pounds/In359 Lbs/In.
In Plane Stiffness, Kg/cm162 Kg/cm
Number of Main Strings18
Number of Cross Strings20
Ratio Cross/Mains.653
Main String Grid7.50
Cross String Grid10.25
Density (% of head filled with string).792
Average Cross String Space.513
Average Main String Space.417
Dynamic
Dynamic Tension, Kp, ERT37
Dynamic Tension, Lbs/in206.9
First Moment, Nm.803
Polar Moment326
Torsional Stability15
Swing Weight, Kg/cm2311
Swing Weight, Ounces10.97
Swing Weight Calculated330.2
Power, RDC39
Control, RDC62
Manueverability, RDC79
Power, Calculated 1749.9
Head Points9.29 (negative = head heavy)
Head Weight, %45.7%
Center of Percussion21.0
Dwell Time, ms, No Swing8.35
Efective Stiffness - lbs29.0
K, Lb/In (SBS) RDC185.9
Recoil Weight160.4
Twist Weight226.8
End Weight 149.2
Tip Weight 189.9
9 O'Clock98.2
3 O'Clock98.8
Butt Cap140.3
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