Category Archives: String

All string information

The Elephant in the Room!

I suspect we all have heard that expression!

It means there is something that everyone tries to ignore, but it is too large to do so!

I recently read an article in Racquet Sports Industries authored by Georgetta L. Morque. The title is “Tackling Tennis Elbow.” Tennis elbow is an important topic and deserves much attention. Georgetta is writing about ways to mitigate tennis elbow after the fact.

So, here is the elephant in the room; STIFF string!

 

Let’s try to prevent tennis elbow, so it does not need to be treated!

When we say stiff, it means a string with less than 4% elongation at 60 pounds which is our testing parameter. Most strings, and for this discussion, strings exhibiting that property will be monofilament PET-based (polyester).

Fully understanding this required a lot of testing, both lab and play, for many playing styles and racquets. To make a long story short, as a racquet technologies business, we decided not to promote polyester strings for most players. That sounds silly, but why take a chance when you don’t have to!

Our success is based on helping you, the player, perform the best you can, so it does not make sense to promote something contrary to that philosophy. Probably 75% of our clients have come to us for something different, so we have a “head start.” 

So why do so many players use it or want to use it? 

We believe it is because they have not been exposed to alternative string materials. Some outstanding players at the pro level use it, so it must be good, and it is for about 10-11 games. Of coursemanufacturers and marketers of polyester string stand to make a nice profit! It is in their best interest to promote products by adding some terminology and material to make the string less stiff.

A polyester string is deficient in power and needs to be walloped, and the harder it is hit, the stiffer it becomes, which is the problem. Developing bodies can’t tolerate that level of impact for long.

Please let us know your experience with strings of any type!

 

SBS…what is it and why should we care?

We have made several posts regarding SBS, which is “String Bed Stiffness” and this is another one!

If you read this post we really need your comment(s), really!

String bed stiffness is the “feeling” when the ball hits the string on a tennis racquet.  Due to the various string materials there will be “soft” and “hard” feelings.  But wait, there’s more!

The string bed is made up of several strings, some longer called the Main string (M)and some shorter called the Cross string(X).  Using “reference” tension each of the sets of string will be pulled at the same machine setting!  It the machine is set at 50 pounds the tension head will stop pulling when it feels 50 pounds of resistance, regardless of what he tension inside the racquet head may be.

SBS is the most effective data for comparing tennis racquet stringing!

Let’s say you come into the world headquarters and we ask you what SBS you would like to have?  Would you know?  Probably not and not many would!  We have grown up using the term “reference tension”, not SBS.

Reference tension is “number” you would ask your racquet technician to set the stringing machine tension system on.  That number will probably be between 30 and 60 pounds (≈13 to 26 Kilo).

So, depending on many other variables, such as string material, string pattern, stringing machine, stringer technique, etc., you can end up with may different versions of the same “reference tension”.

A better way, and one we have been using for over thirty (30) years, is SBS but not everyone has bought into the concept, even though a qualified racquet technician will have a way to measure SBS!  Maybe because it is too much trouble to figure out what your desired SBS from machine X would be from machine A!  It is not!

There have been several really good SBS data collection devices but they have been difficult to use, and pricy!  Not to mention gigantic!

A call to action!
So here is where you come in,

Would you purchase a SBS data collection device?

How much would you pay for such a device?

Would you prefer a mechanical device or an electronic device?

The device must be portable, that is easily carried in a racquet bag or backpack

    Yes or It doesn’t matter

It must be easy to use.

If you use an SBS device would you use a racquet technician that did not know what SBS is or how to measure it?

Thank you for adding your comments to this discussion!  It is important stuff!

 

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 Boom MP 2022

Head has introduced a brand new racquet! So, you say, what’s new about that they do it every year! Yes, but this is a different racquet!

This is the Boom!
In all the years we have been dealing with Head it has become clear that they are not averse to making new things…instead of drastically changing old things.

The Boom is available in a Pro version and a MP version, with the Pro version being a little heavier.

So the Boom, which will be available in January of 2022, (pre order now!) is a new racquet and it is not shy about it!

The head shape is a little different, the shaft is a little different, and the Auxetic material and construction is a little different and all these “littles” add up to a totally different hitting experience!

The shaft transitions from a common box to a trapezoid as it junctions with the yoke (which is the Auxetic area, don’t forget)

The 24mm beam (actually 22, 24.4, 23.3) is a solid choice for advancing players offering just the right amount of stiffness for a little extra “punch”.

We believe the recoil weight could be higher and that is easily accomplished when wanted.  

 

The MP and Pro demo’s are ready for your evaluation! These are very popular demo’s!
ManufacturerHead
Racquet ModelHead Boom MP 2022
Reference Tension55 lbs - 24.9 kg
String
Tecnifibre BiPhase 124
Machine UsedTrue Tension Professional
Static
ASPS, RDC55.0
ASPS, FlexFour64.0
Racquet Flex, RDC62 - After stringing
Racquet Flex, FlexFour42.0
Racquet - In Plane Stiffness344.8 lbs/Inch
Weight, Grams320
Weight, Ounces11.29

Balance, mm327
Balance, Inch12.87
Length, Cm68.6
Length, Inch27.008
Head Width9.83
Head Length12.84
Head Area, cm2639.4
Head Area, Sq. Inch99.1
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.645
Main String Grid7.61
Cross String Grid10.68
Density (% of head filled with string).774
Average Cross String Space.475
Average Main String Space.562
Dynamic
Dynamic Tension, Kp, ERT35
Dynamic Tension, Lbs/in195.7
First Moment, Nm.807
Polar Moment325
Torsional Stability13
Swing Weight, Kg/cm2312
Swing Weight, Ounces11.01
Swing Weight Calculated342.2
Power, RDC45
Control, RDC56
Manueverability, RDC79
Power, Calculated 1936.2
Head Points5.04
Head Weight, %47.7%
Center of Percussion20.80
Dwell Time, ms8.58
Efective Stiffness - lbs29.1
K, Lb/In176.26
Recoil Weight149.42
Twist Weight231.14
End Weight 127.9
Tip Weight 191.8
9 O'Clock96.5
3 O'Clock96.1
Butt Cap126.8

 

What Can Pictures Tell Us About String?

It is said that “a picture is worth a thousand words,” which may be true as long as the picture tells a story.

This story is about natural gut string, and the pictures will show what we can achieve, informationally, with our testing equipment. The two (2) strings are Babolat VS Touch 17 and Luxilon Natural Gut 125.

Both are awesome products, and we use a lot of both of them, but for different reasons, we may be able to understand by the pictures!

Our Questron software scales the images to suit the data so the graphs will not be the same size.

Babolat VS Touch 17

Our testing loads the string from 0 pounds force to 50 pounds and back to zero then up to 50 pounds three (3) times.  This is the “stress/strain” curve.  Fifty (50) pounds is arbitrary and because we are using the same methodology for all string materials it is a good number.  The closer these lines are together the better.

The farther it takes to reach 50 pounds the “higher elongation” the string is.  In this case it is about 44mm.

The important property of this string is the linearity!  That is the “straightness” of the line from beginning to end.  This indicates predictability, stability, and consistency.

This picture tells us the tensile strength and the knot strength.  In this case the knot strength is 52.3 pounds and takes a stretch to very close to 60mm before failure.

Luxilon Natural Gut 125

What is, probably, the first thing you notice about this “picture”? Could it be the squiggly lines? What could be causing this?

We believe it is the “break-in period” players associate with Luxilon gut! We have heard it from the players but have not been able to “see” it! It could be the bonding agents realigning as the load is applied.

You will notice a couple of things: the similarity of the “stress/strain” curve and the displacement to “knot strength” of the two strings. This string will feel a little less “soft” than the Babolat VS Touch 17. The linearity is quite good up to failure.

So, based on these pictures, could you make a recommendation? If so, let us hear them!