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.
|Property||Head Prestige Mid||Yonex VCore Pro 97||Difference||What it Means|
|Main String||MonoGut ZX||MonoGut ZX|
|Cross String||MonoGut ZX||MonoGut ZX|
|End Weight||146.4||147.2||-.8 grams||Nothing|
|Tip Weight||206.0||205.4||.6 grams||Nothing|
|Overall Weight||352.4||352.6||-.2 grams||Nothing|
|Swing Weight||343.0||340.0||3 Kg/cm2||Very Little|
|In Plane Stiffness||411.0||352.9||58.1 Lbs/Inch||Resistance to "Squeezing"
|Stability||15||18||-3 units||Less Stable|
|Position 1 - Butt Cap||137.6||141.3||-3.7 grams||Less weight in the grip|
|Position 2 - 9 O'Clock||108.1||105.1||3 grams||More weight on the left|
|Position 3 - 3 O'Clock||106.5||104.6||1.9 grams||More weight on the right|
|FlexFour Stiffness||41||45||-4||Less stiff in the shaft|
|SBS - RDC||66||58||8||Different testing methods|
|SBS - FlexFour||70.5||66.0||4.5||Different testing methods|
|SBS - Lbs/Inch||225.9||211.5||14.5 Lbs/Inch||Tighter String Bed|
|COF = Cross||.397||.342||.055||More Ball Grip|
|Peak Load||218.0||231.0||-15.1||Softer String Bed @ big hits|
|Head Weight %||47.05%||46.94%||.11%||More weight toward head|
|Dwell Time||5.4 ms||4.9 ms||.5 ms||Longer ball contact|
|Length - Unstrung||68.5 cm||68.5 cm||o.o cm||Nothing|
|Head Size - Calculated||92.4 Square Inch||95.8 Square Inch||-3.4 Square inch||Higher String Bed Stiffness|
|Head Width||9.2 Inch||9.6 Inch||-.4 inch||More 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.