Category Archives: Kinesiology

What’s The Difference?

As tennis players, you must constantly ask “what’s the difference” when it comes to tennis racquets and string! Well, as racquet technicians we ask the same questions!

This post is intended to showcase the differences of string in testing, not playing, however, some of the data may be noticeable to the player in certain situations.

What this graph shows us, in addition to our trying to save a tree by printing on the back of previously used paper, is that each of these stings will provide almost the same performance. This is indicated by the curve and how closely related the strings are.

Tensile Strength Comparison

The differences you do see here can be attributed to the gauge, or diameter, of the string, with the largest diameter (Tour Bite) having the highest tensile strength.  Down in the “hitting” displacement range (way below the 39.9mm!), there is very little difference.

The tensile strength can be a factor as the string begins to “notch” or otherwise come apart.  Each of the strings in this graph is monofilament so notching would be the failure mode in a racquet.

 

Head Prestige Tour 2021

This racquet has the potential to be the hottest new Prestige in a long time. The “Tour” series is not new to the Prestige line but this one has some differences that are meaningful, we think!

This new Tour is a 16×19 string pattern inserted into a 95 square inch hitting area! Compare that to the previous Tour with a 18×19 string pattern in a 99 square inch head(now the new Prestige MP)…so you can see where this one is headed!

All of the new Prestige 2021 racquets will come with the full cap system that has become the “iconic” Prestige accoutrement.  

Also included in the Prestige Tour is the Auxetic material and construction that is intended to provide a better feeling impact and maybe a little more “energy”.  The shaft has a slightly different geometry and is a little shorter than some other models, however, the graphics indicate the shaft is “elongated”.

The “box” beam is a relatively constant 22mm from start to finish and is beautifully done in matt black transitioning into the Prestige maroon.

ManufacturerHead
Racquet ModelHead Prestige Tour 2021
Reference Tension53 lbs - 24.0 kg
String
Victrex 7718 (PEEK)
Machine UsedTrue Tension Professional
Static
ASPS, RDC50.0
ASPS, FlexFour63.5
Racquet Flex, RDC63 - After stringing
Racquet Flex, FlexFour42.5
Racquet - In Plane Stiffness384.6 lbs/Inch
Weight, Grams336
Weight, Ounces11.85

Balance, mm326
Balance, Inch12.83
Length, Cm68.5
Length, Inch26.968
Head Width9.406
Head Length12.78
Head Area, cm2608.9
Head Area, Sq. Inch94.4
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.620
Main String Grid7.20
Cross String Grid9.125
Density (% of head filled with string).695
Average Cross String Space.464
Average Main String Space.445
Dynamic
Dynamic Tension, Kp, ERT34
Dynamic Tension, Lbs/in190.16
First Moment, Nm.844
Polar Moment347
Torsional Stability16
Swing Weight, Kg/cm2331
Swing Weight, Ounces11.68
Swing Weight Calculated357.1
Power, RDC53
Control, RDC47
Manueverability, RDC66
Power, Calculated 1968.0
Head Points5.20
Head Weight, %47.6%
Center of Percussion21.1
Dwell Time, ms9.00
Efective Stiffness - lbs27.9
K, Lb/In160.26
Recoil Weight161.61
Twist Weight223.59
End Weight 136.8
Tip Weight 200.6
9 O'Clock99.5
3 O'Clock101.4
Butt Cap134.9

 

And The Winner Is…

If you know anything about Tecnifibre yo know they make some of the best multifilament strings in the business!

 

The winner is Tecnifibre MultiFeel 17!

This string, MultiFeel, is a very “soft” polyurethane bonded construction that offers playability and a good value!

Tecnifibre MultiFeel !7 Gauge

This graph shows the high elongation and nice elasticity of this string.  The fairly linear slope up to failure would indicate some consistency of shot all the way up to breakage!

The knot strength is pretty good for a thin multifilament and we can say from experience that the know is going to be fine when property “tightened” and large enough to not slip bak into the grommet barrel.

If you are considering a multifilament this would be a good one to try!

String Evaluation Program

Racquet Quest, LLC has for years been doing the extensive evaluation of racquets and string for the benefit of our client’s customization requirements.

Now we are making this evaluation “program” available to anyone that wants to dig deeper into the workings of the string in the racquet!

This is serious stuff and requires significant resources but it is worth it!

Please contact us of you would like to take advantage of our evaluation program!

Take a look at the String Evaluation Program!

 

 

Prince Vortex 300

The new Prince Vortex design is a new offering of an older string pattern with 14 main strings and 21 cross strings in a variable taper beam…whew!  You can see by the throat design that the main strings are longer that a conventional throat design.  The longer the main strings the more energy they can return…sort of, and in some cases!

Vortex 300

The beam starts at the grip with a strong 25mm then tapers into a 23mm at the throat and then back to 25mm at the tip.  Do not let the beam dimensions fool you!  The RDC flex of 59 after stringing is quite acceptable for most every player style.

We have been taking coefficient of friction (COF) data for years  but have not included it this review format, until now.  The 14×21 string pattern is unique enough that it is worth including.  You will see the numbers on the review specs so we won’t go into them now, however the numbers are interesting.

The 14 main strings contribute to a very “open” area right about where most extreme “spin” shots are hit according to our data of string failure positions.

The frame geometry is sort of “Aero” like.  The shaft is trapezoidal that transitions into a “reverse” trapezoid around the head.  It makes the racquet look stiffer than it is!

Take a look at the specs then pick up a demo to see what the numbers mean to you!

ManufacturerPrince
Racquet ModelPrince Vortex 300
Reference Tension56 lbs - 25.4kg
String
Victrex 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC45
ASPS, FlexFour58.5
Racquet Flex, RDC59 - After stringing
Racquet Flex, FlexFour40.0
Racquet - In Plane Stiffness526.3 lbs/Inch
Weight, Grams322
Weight, Ounces11.36
Balance, mm320
Balance, Inch12.60
Length, Cm68.6
Length, Inch27.008
Head Width9.94
Head Length12.94
Head Area, cm2652
Head Area, Sq. Inch101.1
Number of Main Strings14
Number of Cross Strings21
Ratio Cross/Mains.512
Main String Grid7.30
Cross String Grid9.50
Density (% of head filled with string).686
Average Cross String Space.452
Average Main String Space.521
Dynamic
Dynamic Tension, Kp, ERT32
Dynamic Tension, Lbs/in176.98
First Moment, Nm.790
Polar Moment336
Torsional Stability17
Swing Weight, Kg/cm2319
Swing Weight, Ounces11.25
Swing Weight Calculated329.7
Power, RDC47
Control, RDC52
Manueverability, RDC74
Power, Calculated 1921.1
Head Points7.24
Head Weight, %46.6
Center of Percussion21.7
Dwell Time, ms9.48
Efective Stiffness - lbs30.2
K, Lb/In144.23
Recoil Weight165.41
Twist Weight237.56
End Weight 134.5
Tip Weight 189.0
9 O'Clock96.2
3 O'Clock96.1
Butt Cap131.4
Coefficient of Friction: M.400
Coefficient of Friction: X.262