Category Archives: Accuracy
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.
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.
This years Head Prestige Pro is last years Prestige MP. This name change was made to synchronize all the 18×20 string patterns as the “Pro” model…I think!
So, what’s in a name? A thin beam, heavy (sort of), 18×20 pattern, players racquet, that’s what! The Prestige Pro also includes the new Auxetic material and construction for a refined feel.
For some reason Head Prestige racquets have been called “stiff” by some and this is certainly not the case and never has been. This racquet is not stiff! As with any racquet the string selection can have a huge effect on “stiffness” so take a look at the effective stiffness!
I believe this is going to be a “control freaks” racquet! This racquet could also be a baseliners dream come true. The weight will drive through the ball and the swing weight will allow for some last nano-second stroke adjustments.
Take at look at the data below then go to the Prestige 2021 Comparative Data post to see all the models in one place.
|Racquet Model||Head Prestige Pro 2021|
|Reference Tension||52 lbs - 23.6 kg|
|String||Head Reflex MLT 17|
|Machine Used||True Tension Professional|
|Racquet Flex, RDC||58 - After stringing|
|Racquet Flex, FlexFour||36.0|
|Racquet - In Plane Stiffness||326.1 lbs/Inch|
|Head Area, cm2||627.4|
|Head Area, Sq. Inch||97.2|
|Number of Main Strings||18|
|Number of Cross Strings||20|
|Main String Grid||7.56|
|Cross String Grid||10.24|
|Density (% of head filled with string)||.791|
|Average Cross String Space||.513|
|Average Main String Space||.417
|Dynamic Tension, Kp, ERT||35|
|Dynamic Tension, Lbs/in||195.76|
|First Moment, Nm||.832|
|Swing Weight, Kg/cm2||318|
|Swing Weight, Ounces||11.22|
|Swing Weight Calculated||345.8|
|Head Weight, %||46.4%|
|Center of Percussion||20.7|
|Dwell Time, ms||8.74|
|Efective Stiffness - lbs||27.7|
Jumping back and forth between reviews and data is not fun nor is it efficient so we have been posting comparative data. Now all the important stuff is in one place.
All of the data is based on a “play ready” racquet. That means an overgrip and vibration damper, and unless otherwise noted…string!
As you are looking at the data try to determine which numbers mean the most to you and how you could use them. For example, the Pro has an overall weight of 342 with a swing weight 318. How does that compare to the MP?
Keep in mind that weight and swing weight can increased but not easily decreased. No, making the racquet more “head light” statically does not reduce the swing weight as recorded on testing devices that grab the racquet 10cm from the end! That is why static balance (CG) should not be used as a performance metric.
Click here to see the data!
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!
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.
|Racquet Model||Head Prestige Tour 2021|
|Reference Tension||53 lbs - 24.0 kg|
|String||Victrex 7718 (PEEK)|
|Machine Used||True Tension Professional|
|Racquet Flex, RDC||63 - After stringing|
|Racquet Flex, FlexFour||42.5|
|Racquet - In Plane Stiffness||384.6 lbs/Inch|
|Head Area, cm2||608.9|
|Head Area, Sq. Inch||94.4|
|Number of Main Strings||16|
|Number of Cross Strings||19|
|Main String Grid||7.20|
|Cross String Grid||9.125|
|Density (% of head filled with string)||.695|
|Average Cross String Space||.464|
|Average Main String Space||.445
|Dynamic Tension, Kp, ERT||34|
|Dynamic Tension, Lbs/in||190.16|
|First Moment, Nm||.844|
|Swing Weight, Kg/cm2||331|
|Swing Weight, Ounces||11.68|
|Swing Weight Calculated||357.1|
|Head Weight, %||47.6%|
|Center of Percussion||21.1|
|Dwell Time, ms||9.00|
|Efective Stiffness - lbs||27.9|
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.
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!
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!