Racquet v Racquet!

If tennis racquets could play each other without the help, or hindrance, of a human, I wonder how they would do?

When we finish a series of racquets for a client, we have data that detail the properties, so, why not use this process to see how two (2) different racquets compare and, what, if anything, would contribute to one racquet “beating” another. We have this data for each client, so, we could play one client racquet against another! Of course to the player this is subjective but let’s look at a quick comparison and discuss what could make a difference and what that difference may be.

PropertyHead Prestige MidYonex VCore Pro 97DifferenceWhat it Means
Main String
MonoGut ZX
MonoGut ZX
Cross StringMonoGut ZXMonoGut ZX
End Weight146.4147.2-.8 gramsNothing
Tip Weight206.0205.4.6 gramsNothing
Overall Weight352.4352.6-.2 gramsNothing
Swing Weight343.0340.03 Kg/cm2Very Little
Polar Moment358.0358.00.0Nothing
In Plane Stiffness411.0352.958.1 Lbs/InchResistance to "Squeezing"
Static Balance321.8321.1.7mmNothing
Stability1518-3 unitsLess Stable
Position 1 - Butt Cap137.6141.3-3.7 gramsLess weight in the grip
Position 2 - 9 O'Clock108.1105.13 gramsMore weight on the left
Position 3 - 3 O'Clock106.5104.61.9 gramsMore weight on the right
CheckSum352.23511.2 gramsConfirmation
RDC Stiffness5960-1Nothing
FlexFour Stiffness4145-4Less stiff in the shaft
SBS - RDC66588Different testing methods
SBS - FlexFour70.566.04.5Different testing methods
SBS - Lbs/Inch225.9211.514.5 Lbs/InchTighter String Bed
COF= Main.387.392-.005Nothing
COF = Cross.397.342.055More Ball Grip
Peak Load218.0231.0-15.1Softer String Bed @ big hits
Head Weight %47.05%46.94%.11%More weight toward head
Dwell Time5.4 ms4.9 ms.5 msLonger ball contact
Length - Unstrung68.5 cm68.5 cmo.o cmNothing
Head Size - Calculated92.4 Square Inch95.8 Square Inch-3.4 Square inchHigher String Bed Stiffness
Head Width9.2 Inch9.6 Inch-.4 inchMore Twisting

As you can see, there is little difference in these racquets so it could be concluded that they will play the same. However, let’s start at the top and look at the properties that could make a difference.

MonoGut ZX String is quite “soft,” and both racquets were strung at the same reference tension so not much there.

The End, Tip, and Overall Weight are virtually the same as is Swing Weight and Polar Moment.

In Plane Stiffness is the racquets resistance to becoming more narrow when cross strings are tensioned, or wider when main strings are installed. In Plane Stiffness can contribute to a more “firm” or more “flexible” string bed.

Static Balance is the same, but Stability is higher for the Yonex, and I contribute this to the slightly “wider” head. The farther the sides are from the neutral axis, the more stable. However, the Head has a higher 9 and 3 O’Clock weight which should contribute to stability.

Position 1, 2, and 3 are weights taken at three locations on the racquet. Places 2, and three on the Yonex could be increased slightly to increase swing weight.

The checksum is there for me to confirm entries.

RDC and FlexFour stiffnesses indicate that the Yonex should be a little more “powerful” (≈13%) which is confirmed in another piece of data not included here.

SBS RDC and FlexFour are different tests of the string bed. The FlexFour data is used to calculate SBS Lbs/Inch. This data would suggest the Yonex racquet would generate a little more “grunt.”

COF=Main: is the resistance of a ball sliding up the main strings.

COF=Cross: is the resistance of a ball sliding across the cross strings. So, if the ball can catch the string (higher number) the more quickly the ball will begin to rotate. At this moment the coefficient of friction of “string on string” will take over.

String on String” coefficient of friction is recorded in another data base and can be used to choose complimentary strings for any occasion.

Posted on February 16, 2019, in Good News! and tagged . Bookmark the permalink. Leave a comment.

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