Numbers, numbers, numbers! What do they mean?

Feb 16

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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;

Numbers are your friend!
ManufacturerHead
Racquet ModelHead Radical MP 2023
Reference Tension55 (what you tell the stingers to set the stringing machine).
This should be replaced by String Bed Stiffness (SBS)
String
MonoGut ZX Pro
Machine UsedTrue Tension Professional
Static
String Bed Stiffness - RDC53.0 Units (Babolat RDC)
String Bed Stiffness -FlexFour64.9 pounds (Flex Four)
String Bed Stiffness - SBS51.8 pounds (Racquet Quest string bed stiffness SBS Master)
String Bed Stiffness - ERT35 Kg/Cm (previously Beer's ERT1000)
Racquet Flex, Babolat RDC65 - After stringing (unstrung racquets will be slightly stiffer. Loaded from the tip)
Racquet Flex, FlexFour44.5 (Loaded from the COP)
Racquet - In Plane Stiffness379.7 lbs/Inch (stiffness across the 3 ad 9 o'clock positions of the racquet head)
Weight, Grams326
Weight, Ounces11.50
Balance, mm333
Balance, Inch13.11
Length, Cm68.57
Length, Inch27.00
Head Width9.63
Head Length12.79
Head Area, cm2623.0
Head Area, Sq. Inch96.7
Beam Height @ Grip, mm21.0 (how thick the racquet is looking at the side)
Beam Height @ Mid, mm22.5 (how thick the racquet is looking at the side)
Beam Height @ Tip20.5 (how thick the racquet is looking at the side)
Beam Width @ Grip, mm12.5 (how thick the racquet is looking at the front or face view)
Beam Width @ Throat, mm11.5 (how thick the racquet is looking at the front or face view)
Beam Width @ Mid, mm12.8 (how thick the racquet is looking at the front or face view)
Beam Width @ Tip, mm12.8 (how thick the racquet is looking at the front or face view)
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.634 ( typically the natural ratio)
Main String Grid7.18 (the distance between the two outer most main strings)
Cross String Grid9.44 (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
Dynamic Tension, Kp, ERT35 (string bed stiffness in kilos per centimeter)
Dynamic Tension, Lbs/in195.76 (DT converted to pounds per inch)
First Moment, Nm.841 (sometimes called pickup weight)
Polar Moment347 (torsional weight)
Torsional Stability16 ( resistance to twisting on off center hits)
Swing Weight, Kg/cm2331 (the dynamic weight and the most significant property)
Swing Weight, Ounces11.68
Swing Weight Calculated361.5 (calculated from the butt end to the tip)
Power, RDC52 (property calculated by Babolat RDC)
Control, RDC49 (property calculated by Babolat RDC)
Manueverability, RDC66 (property calculated by Babolat RDC)
Power, Calculated 2101.4 (calculation based on several racquet properties)
Head Points3.15 ( a point is generally consider to be .125 inches/3.18mm)
Head Weight, %48.5%
Center of Percussion21.1 (highest COR)
Dwell Time, ms8.74 (length of time the ball is in contact with the string without a swing)
Efective Stiffness - lbs29.2 ( the calculated combined stiffness of the racquet and sting bed)
K, Lb/In169.87 (string bed stiffness in pounds/inch)
Recoil Weight156.44 (resistance to twisting about the grip)
Twist Weight226.48 (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'Clock105.1 (three scale system to assure symmetry)
3 O'Clock104.7(three scale system to assure symmetry)
Butt Cap115.6 (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)

Posted on February 16, 2023, in Evaluation, Learning. Bookmark the permalink. Leave a comment.

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