Monthly Archives: April 2021
Correct Size Does Matter!
Grip size, in this case, does matter! However, for several years the largest grip size available has been a 4 ⅝, or just 5 for short.
This is simply the circumference of the finished grip forward of the butt cap. Of course the butt cap is of a size that will capture the butt of your hand for comfort and control.
But what happens if you need a grip size larger than 4 ⅝? In years gone by a shrink tube was applied to the current grip pallet and the size was increased accordingly. Typically only two (2) shrink tubes could be used and even then the grip facets became “rounded”.
Lucky for us, and you of course, we can now print grip pallets in any size required! The largest one so far is a 5 1/4 for a player in New York using a Babolat Pure Aero.
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- From this to…
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- …This!
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- Pallet with Butt Cap
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- Raw Shaft
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- Previous Grip Pallet
Each printed pallet is made specifically for a racquet, not just a “one size fits all” approach due to very subtle variations in size, especially the inner shaft.
Inner Shaft
In this case the pallets were longer to accommodate large hands so the length of the racquet was increased through the use of these pallets and a printed extender.
The printed pallet must fit securely and the best way to assure the fit is to have the racquet.
Pallet with Butt Cap
What Can String Failure Tell Us – Part Deux
In Part Un we discussed the difference between shanking (mis-hit) and friction failure. It was obvious that the string was broken. But what happens when it is not so obvious?
Part Deux, this part, will examine the frictional notching failure of monofilament string and how we can be prepared for it! To further refine this discussion we will be comparing PET polyester has PEEK monofilament string. The reason is that each material while both will notch one requires more time to reach the critical dimensional decrease that is a failure!
In almost every Racquet Quest Podcast we talk about tension v string diameter and agree that once 50% of the string diameter is notched away the string is vulnerable! So a .050 (1.27mm) diameter string that has a tensile strength of 120 pounds at 50% notching will have 60 pounds of tensile strength remaining.
Notched v un notched string
This graph is a string that was broken during use. The string was removed from the racquet. The top line is the tensile strength in the area of no notching so you can see that it is pretty strong still and has stabilized due to use. That stabilization is indicated by the very tight stress/strain grouping.
However, things go sideways when the notched area of the string is put under stress. The string failed at a force of 63.8 pounds, or about 59% of the used tensile strength. Not bad!
So, notching is failure-inducing but how long it takes to create the fatal notch differs with string material. This particular set of strings had about six (6) hours of play.
In Part Trois, we will look at PEEK material under the same conditions!
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!
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!
Players String Evaluation
For years we have requested player evaluation input to help us provide a comprehensive selection of quality tennis racquet string.
Our new Player String Evaluation form below makes it really quick and easy to give us your evaluation input. If Racquet Quest prepared your racquet there will be two (2) labels on the inside of the racquet shaft. One label will be your name with date, string, tension, and racquet number. The other label will be a bar code that includes the racquet number.
You can use this information when filling out the Player String Evaluation form. Thank you for your input!
Racquet Quest, LLC
