Category Archives: Tension

Head Speed Pro Black

As you probably know by now Novak Djokovic plays with a version of the Head Speed but in black, not black and white! So it was only a matter of time until the all-black Speed Pro became available.

Until now we only had the black and white Speed Pro demo but now we have the black one!

This review will include the white and black version of the Speed and we will include a comparison to the Wilson Blade Pro!

These are each extraordinary racquets!  You will discover subtle differences in the specifications, especially the Wilson Blade Pro being a 16×19 pattern and the Head Speed Pro, in this case, is 18×20.  The geometry and frame of the 16×19 and 18×20 are the same so the numbers are meaningful!

 

ManufacturerHead
Racquet ModelHead Graphene 360 + Speed Pro Black
Reference Tension54 lbs - 24.5 kg
String
Head Reflex MLT
Machine UsedTrue Tension Professional
Static
ASPS, RDC56
ASPS, FlexFour66.5
Racquet Flex, RDC57 - After stringing
Racquet Flex, FlexFour50.5
Racquet - In Plane Stiffness325.2 lbs/Inch
Weight, Grams334
Weight, Ounces11.78

Balance, mm325
Balance, Inch12.80
Length, Cm68.6
Length, Inch27.008
Head Width9.618
Head Length13.10
Head Area, cm2636.1
Head Area, Sq. Inch98.6
Number of Main Strings18
Number of Cross Strings20
Ratio Cross/Mains.662
Main String Grid7.565
Cross String Grid10.30
Density (% of head filled with string).7735
Average Cross String Space.513
Average Main String Space.413
Dynamic
Dynamic Tension, Kp, ERT35
Dynamic Tension, Lbs/in195.7
First Moment, Nm.836
Polar Moment341
Torsional Stability15
Swing Weight, Kg/cm2326
Swing Weight, Ounces11.50
Swing Weight Calculated352.8
Power, RDC42
Control, RDC59
Manueverability, RDC69
Power, Calculated 1832.1
Head Points5.51
Head Weight, %47.0%
Center of Percussion21.016
Dwell Time, ms8.502
Efective Stiffness - lbs28.25
K, Lb/In179.49
Recoil Weight159.3
Twist Weight231.4
End Weight 134.5
Tip Weight 198.0
9 O'Clock99.0
3 O'Clock99.6
Butt Cap134.0

 

And now for the white and black version:

ManufacturerHead
Racquet ModelHead Graphene 360+ Speed Pro
Reference Tension56 lbs - 25.4 kg
String
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
Static
ASPS, RDC55
ASPS, FlexFour66.5
Racquet Flex, RDC60 - After stringing
Racquet Flex, FlexFour43
Weight, Grams327
Weight, Ounces11.53
Balance, mm323
Balance, Inch12.72
Length, Cm68.5
Length, Inch26.97
Head Width9.69
Head Length13.06
Head Area, cm2641.2
Head Area, Sq. Inch99.4
Beam Width, mm, Shaft, Center, Tip23, 23, 23
In Plane Stiffness, Pounds/In335.2 Lbs/In.
In Plane Stiffness, Kg/cm 152.0 Kg/cm
Number of Main Strings18
Number of Cross Strings20
Ratio Cross/Mains.668
Main String Grid7.62
Cross String Grid10.37
Density (% of head filled with string).768
Average Cross String Space.513
Average Main String Space.414
Dynamic
Dynamic Tension, Kp, ERT37
Dynamic Tension, Lbs/in206.94
First Moment, Nm.812
Polar Moment336
Torsional Stability16
Swing Weight, Kg/cm2320
Swing Weight, Ounces11.29
Swing Weight Calculated341.2
Power, RDC45
Control, RDC57
Manueverability, RDC73
Power, Calculated 1908.2
Head Points6.14 (negative = head heavy
Head Weight, %47.2%
Center of Percussion21.2
Dwell Time, ms, No Swing8.58
Efective Stiffness - lbs28.7
K, Lb/In (SBS) RDC176.28
Recoil Weight159.71
Twist Weight229.85
End Weight 133.4
Tip Weight 192.8
9 O'Clock97.1
3 O'Clock97.5
Butt Cap131.0
This Wilson Blade Pro was not strung by Racquet Quest. The specifications are included as a comparison only…not a string recommendation.

And now for the Wilson Blade Pro:

ManufacturerWilson
Racquet ModelWilson Blade Pro
Reference Tension54 lbs - 23.6 k2
String
ALU Power Rough
Machine UsedUnknown
Static
ASPS, RDC35
ASPS, FlexFour53
Racquet Flex, RDC62 - After stringing
Racquet Flex, FlexFour48
Racquet - In Plane Stiffness387.1 lbs/Inch
Weight, Grams337
Weight, Ounces11.89
Balance, mm327
Balance, Inch12.87
Length, Cm68.6
Length, Inch27.008
Head Width9.6
Head Length12.80
Head Area, cm2623.3
Head Area, Sq. Inch96.6
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.634
Main String Grid7.37
Cross String Grid10.40
Density (% of head filled with string).7934
Average Cross String Space.547
Average Main String Space.461
Dynamic
Dynamic Tension, Kp, ERT27
Dynamic Tension, Lbs/in151.0
First Moment, Nm.850
Polar Moment358
Torsional Stability16
Swing Weight, Kg/cm2342
Swing Weight, Ounces12.06
Swing Weight Calculated360.35
Power, RDC55
Control, RDC42
Manueverability, RDC59
Power, Calculated 2069.0
Head Points5.04
Head Weight, %47.07
Center of Percussion21.535
Dwell Time, ms10.755
Efective Stiffness - lbs22.37
K, Lb/In112.18
Recoil Weight170.8
Twist Weight234.0
End Weight 135.0
Tip Weight 202.9
9 O'Clock100.8
3 O'Clock103.7
Butt Cap132.2

Dealing with Options, and What are the Options?

The little video you see above is just a reminder that we do not promote polyester based string for underage players!  So, what is underage?  Oh, under 100 would be a good number, I think!

OK, smart alec what are the options?

  • No Polyester

PEEK/Zyex

Well, there are many, however, if the option is only relative to “no polyester” the best option is PEEK material.  This material is usually referred to by the brand name Zyex which is the fiber division of Victrex of England and known by the Ashaway name as well.  This material is normally found as a monofilament construction as is most polyester materials.

PEEK/Zyex offers exceptional durability and energy!

Multifilament

  • Premium Playability

Natural gut still is the number one playing string available.  We use Babolat and Luxilon natural gut but there are other options like Pacific, Klip, and others.

  • Excellent Playability

Multifilament construction can act as a spring and return both performance, power, and comfort.  Typically the more individual fibers the better.  These fibers are usually bonded with a soft adhesive and show signs of “fraying” during use.

Strings in this category include Tecnifibre, Ashaway, Babolat, Head, Yonex, and Gosen and others.  Expect to pay $42.00 + for these strings installed.

  • Playability

These multifilament strings are typically constructed using fewer larger diameter fibers to enhance durability.  The same “fraying” occurs with this grade of string as well however the larger diameter will last a bit longer usually.

Strings in the category include Tecnifibre, Babolat, Head, Yonex, IsoSpeed, Gamma, and others.  Expect to pay between $35.00 and $40.00 for these strings installed.

Synthetic Gut

  • Value

There are probably 10000 strings that fall under this umbrella!  9999 of these strings will be a nylon core with one or two overwraps bonded to the outer surface.  This material and construction has been around for many, many years and has offered great service to millions of tennis players…and is still in major use today!

Strings in this category include at least one, and probably many more, set from every major brand!  If you are really cost-conscious do not overlook this material. Expect to pay $27.00 to $35.00 for these strings installed.

And lastly,  what is our gripe with polyester?  Click on the link below to find out!

Click here to go to a comprehensive post that will explain our position.

As always, our position is “there are no bad strings just bad applications!”

 

What Can String Failure Tell Us?

Well, in the simplest terms, failure tells us it is time to have the request strung! However, there may be subtleties in string failure that can help us in our quest for tennis racquet performance.

Such as?

Is the failure shear related or tensile strength related? Was friction the major contributor to the failure? Where did the failure occur (on the racquet, not the court)? Was the failure during play or in the bag?

Shear-related failure is when the string breaks very near the racquet frame. This failure is called a mis-hit or shank! It is like cutting the string with a pair of scissors!

Shear Failure

Friction Failure

Friction failure is caused by just that, friction!  Friction is caused by the string moving on each other. That rubbing creates friction and notches the string where it will fail.

If the racquet failed during play and it is not shear-related, the tensile strength of the string was exceeded. If a string has a tensile strength of 120 pounds and the tension is 60 pounds leaving 60 pounds to be used to hit the ball. Some big hitters can generate at least that much force on a solid forehand!

The graphs show the tensile strength and relative elongation of different material.

This graph shows the tensile strength of the string to be about 115 pounds.  Given the movement of this string-on-string, the frictional notching can contribute to relatively early failure based on the hitters force.

This graph shows the tensile strength of the string to be about 155 pounds but it has to travel (stretches) further to reach that force.

So, you can see, with this information we can make better decisions when asked to suggest a string, or strings, for a client!

Which Comes First!

We all have heard the question “which comes first the chicken or the egg”?  However, my question is “Which comes first the game or the string”?

I believe they happen simultaneously.  But first a quick story.

In 2005 I was attending a Head product introduction on the island of Mallorca, Spain,  Yes, that one!

The product introduction was exciting but what I am going to tell you about now was even more meaningful.

The Director of one of the top US Tennis Training organizations, at that time, was there and we were discussing teaching techniques and what he said after being in this part of Europe was “we need to start teaching our players how to hit this way!”  Well, “this way” was the way of low-powered strings that were popular in Europe but not so much in the US, yet.

So, it began!  The players could not hit harder, like the Europeans, unless they used the same string material as the Europeans and that was very stiff and mostly PET polyester.

So, the idea was the “egg” and the string was the “chicken”, sort of!  I guess the feeling was that “if Americans are going to compete we must use the same equipment”.

Our history confirms that almost no one plays better with stiff string and durability is suffering!

Now, I believe the professional game can go on about its way but otherwise, we need to consider changing the game by returning to a combination of comfort and playability.

Our history shows us that the “high performance” life span of many polyester strings is about 2-3 hours, or less, maybe about 10-12 games.  We don’t believe this is quite long enough for most players.  But, how do you quantify “performance”?  It may be different things for different players.

There are many components to performance but what if it was associated with UTR data?  Racquet Quest can track UTR numbers and make some determinations based on that data.  If a UTR is stable or increasing it is a good bet that the performance of the player and equipment is OK.  However, if the UTR is slipping it is a good indication that something is not working as it should…but what?

We have found that, in some cases, it is injury or discomfort, that is causing the slippage!  Stop it!  The following data is for a 12 month period and acquired from the UTR website.  Even small positive changes are tough!  But negative changes seem to have an enormous impact more quickly than positive changes!

For example:

PlayerRacquetStringUTR1UTR2Delta
AHead Speed PEEK12.8412.86+ .02
BBabolat Pure AeroPolyester10.919.56-1.35
CHead Radical MPAPEEK4.505.61+1.11
DWilson Pro Staff 97PEEK5.07.03+2.03
EBabolat Pure AeroPEEK3.85.64+1.84
FWilson Blade 98 Polyester10.09.41-.59
GHead Radical ProNatural Gut3.75.15+1.45

This information is provided as a small sample comparison instrument and is not intended to pry anyone away from their favorite setup!  Even if it hurts!

 

 

 

 

Friction v Tension…what wins?

We all know what friction is.  It keeps our cars from sliding around, it keeps us from slipping and in general makes movement possible!

Friction also plays an important part in the string bed of your tennis racquet.  Friction between the strings and the ball create friction which in turn creates rotation.

What are, however, some of the downsides of friction in the string bed during, and after, the stringing process?

Friction v Tension

For more detailed information and a graph showing the forces involved go to our membership site, GASP.network, but in the meantime this image will show the frictional forces at work!

This machine tension head will pull the string (blue) in the direction of the center of the racquet support structure instead of directly out the middle of the grommet.

It is obvious that this will create considerable friction and result in lower tension inside the grommet than outside the grommet.

Our equipment and technique eliminates this friction resulting in a uniform string bed.