Category Archives: Tips
When we do the testing and “number taking” for our demo racquets, we try to think as the consumer may think and include comments that may help the consumer make the best decision.
We do not want to make these posts so dull that you go to sleep, but data is essential, so we are going to include it…so stay awake!
Data is particularly relevant to the Prestige Series from Head.
This review is for the Prestige Tour, and it points to the differences between Prestige racquets that may go unnoticed or misunderstood.
The Prestige Tour is a 99 (645 cm²)square inch racquet with an 18 x 19 string pattern. If you have read the post on the Prestige MP, you may wonder, what’s the difference?
You may notice that the Prestige Tour has one (1) fewer cross string. Not a big deal. You may see that the Prestige Tour has one (1) square inch larger head size. Also, not a big deal. What you may not notice is the Prestige Tour has an in-plane stiffness of 400, and the Prestige MP has an in-plane stiffness of 359. That is a big deal! Even with a bigger head and fewer strings, the Prestige Tour has a higher string bed stiffness than the Prestige MP. The higher the in-plane stiffness, the less the racquet will “bend” during impact.
The Prestige Tour is more stiff overall (62 v 58) than the Prestige MP, and the 21.5mm beam contributes to that stiffness.
So, take a look at the numbers for this racquet to see if you can find other exciting differences!
Racquet Model Head Graphene 360+ Prestige Tour
Reference Tension 55 lbs - 24.9 kg
Victrex PEEK fiber Experimental 7718
Machine Used True Tension Professional
ASPS, RDC 55
ASPS, FlexFour 71
Racquet Flex, RDC 62 - After stringing
Racquet Flex, FlexFour 49
Weight, Grams 325
Weight, Ounces 11.46
Balance, mm 327
Balance, Inch 12.87
Length, Cm 68.6
Length, Inch 27.008
Head Width 9.56
Head Length 13.12
Head Area, cm2 635.3
Head Area, Sq. Inch 98.5
Beam Width, mm, Shaft, Center, Tip 21.5, 21.5, 21.5
In Plane Stiffness, Pounds/In 400.0 Lbs/In.
In Plane Stiffness, Kg/cm 181.4 Kg/cm
Number of Main Strings 18
Number of Cross Strings 19
Ratio Cross/Mains .690
Main String Grid 7.81
Cross String Grid 10.00
Density (% of head filled with string) .724
Average Cross String Space .526
Average Main String Space .396
Dynamic Tension, Kp, ERT 35
Dynamic Tension, Lbs/in 195.7
First Moment, Nm .819
Polar Moment 334
Torsional Stability 18
Swing Weight, Kg/cm2 316
Swing Weight, Ounces 11.15
Swing Weight Calculated 347.5
Power, RDC 46
Control, RDC 55
Manueverability, RDC 76
Power, Calculated 1929.2
Head Points 4.88 (negative = head heavy)
Head Weight, % 47.7%
Center of Percussion 20.8
Dwell Time, ms, No Swing 8.58
Efective Stiffness - lbs 29.1
K, Lb/In (SBS) RDC 176.3
Recoil Weight 150.9
Twist Weight 222.7
End Weight 131.7
Tip Weight 195.3
9 O'Clock 100.7
3 O'Clock 101.4
Butt Cap 124.0
The essential function of string in your tennis racquet is to return energy to the ball as it collides with the racquet. It is evident that if there is no string or a broken one, the racquet can not do what it is intended to do, and your shot is going nowhere or worse, everywhere!
There are about thirty (30) string brands, and each brand has about ten (10) different models, and maybe three (3) different colors, so there are nine hundred (900) possible selections! Nine hundred is way too many strings!
You and we need to consolidate string data so we can make the right decision for you, your playing style, and your physical capabilities.
We test every string for elongation, creep, (stability), with a little bit of elasticity data observed. This testing returns our exclusive Power Potential© for each string, and that is the basis of our decision-making process. Naturally, the higher the elongation, the more power the string will return to the ball, and conversely, the lower the power potential, the less power that “can” be generated. You can observe this fundamental by dropping a tennis ball on a concrete floor and then on a strung tennis racquet from the same drop height and see which one bounces the highest.
I use “can” because power, to a great extent, comes from how hard you swing the racquet, which, of course, brings the prospect of overdoing it and subsequent injury! A low power string demands a more powerful swing that involves the entire arm, hips, and legs.
Low power, in the form of a stiff string, has been associated with control, therefore, the increased use of stiff strings. However, with stiffness comes another downside, and that is stability. Stiff strings typically lose tension quickly and need to be changed frequently. So here is the real problem; the string may not be broken, but it is not playing well at all. There is a difference between durability and performance! If your goal is long term performance, a stiff string is not the answer.
What, then, is the answer?
Choose a string with an elongation of 10% or higher! Oh, great! You say. How am I going to know that!
Well, beginning January 1, 2020, I will be posting the power potential of every string we have tested over the years! There are over 500 items on the current list sorted by brand. The color coding is RED if 5% or less, GREEN if 10% or higher, and BLUE for everything else. Note, however, that natural gut is included in this data and will probably not reach the 10% Power Potential© threshold, but is still the best performance string available. This is due to the dynamic properties of the natural fibers, so, until there is a separate classification gut will be included as is.
A previous post, “What is Soft?” goes into graphical detail.
As new strings are added, some older ones may be deleted because they are no longer manufactured. However, some very old ones may remain due to their “legacy” status. This chart is a preliminary format but will get us map toward the right decision!
I started thinking about this as I made my way to a routine doctor’s appointment last week. Here is the scenario I formed while waiting:
The doctor has been seeing all sorts of patients already today and I suspect the first glance at each one elicited some sort of reaction, quielty probably, like this; “Good Greif, that guy is fat! Bad trousers, terrible shoes, nice shirt, whats with the hair, dude?” etc, etc.
So what do you think happens when a racquet shows up for a checkup?
“Good grief, that is an old racquet, who would ever buy one of those, this person is too good for that racquet,” etc, etc.
As humans we can communicate how we feel to the doctor but your racquet can not, so it has other ways to tell you if it is healthy or not. Here are a few signs of an unhealthy racquet:
- Grommet set, and specifically the protective head bumper is worn out. If this is not fixed quicky the racquet will die!
- Grommet set individual barrels are broken or missing. If this is not fixed the strings will die!
- Overgrip is disgustingly dirty requiring exam gloves to remove it! Doctors use exam gloves too and you know what that means!
- Under grip is essentially rendered to powder, requiring exam gloves to remove it.
What is not so obvious sometimes is that strings need to be replaced. Even before they break! What!
Yes, strings loose tension over time and in some case rather quickly! By knowing what the original string bed stiffness was we can determine how much “stiffness” has been lost. For most players a degradation of 20% is maximum.
Depending on the string material a loss of 8 to 9% overnight is not uncommon…so that leaves 11 to 12% for playing.
Take a look at our String Frequency Calculator to get a better idea of stringing frequency required to keep your racquet really working for you.
To keep you playing at your best you need to keep your racquet at it’s best!
In addition to individual model specifications we like to do a consolidated series comparison so we can glance at the differences between racquets. Following is that comparison. All the data is taken with strung racquets with a vibration damper but no overgrip.
So, what is important in this data? Well, to us, everything or we wouldn’t include it but we like to explain some of the not so obvious numbers.
End Weight: the weight of the butt end of the racquet when using two (2) electronic scales
Tip Weight: the weight of the top end of the racquet when usisng two (2) electronic scales
Why important: this accurately calculates static balance and allows easy maching of multiple racquets
Swing Weight: the higher the swing weight the higher the energy colliding with the ball.
Why important: this is the most meaningful number in terms of momentum into the ball.
InPlane Stiffness: this tell us how stiff the racquet is when a load is apllied to the 3 and 9 o’clock positions.
Why important: a higher number means the racquet is stiff in that direction affecting string bed stiffness.
Stability: this tell us how the racquet reacts to ball impact.
Why important: the higher the number the more power and control that can be contributed to the racquet.
Position 1, 2, and 3: three (3) electronic scales are used to weigh the racquet.
Why important: we can match the rotational inertia of each racquet.
Peak Load: this tells us the peak force of the ball impact on your body. Higher loads contribute to injury.
Why important: we can make adjustments to the string bed stiffness to keep the peak loads safe.
Everything else should be clear but if you have questions please “Ask John”