Category Archives: Accuracy
Head Gravity Tour 98-Pre Release Version
If you have listened to our latest podcast, you will know a little about the new Head Gravity Tour 98, to be released in January 2025!
The difference between what you may see online and what Racquet Quest, LLC has is we have taken a raw racquet and applied the desired specifications to it.
We see this as a racquet suitable for many playing styles and levels, so we began with a swing weight of 321 and an overall weight of 327.
After Stephanie’s brief video about her reactions to this Gravity Tour 98 racquet, we will return to associate her comments with the numbers in our review! Wouldn’t that be fun?
In Stepahines’ video, she adds several years to the age of her Gravity MP, calling it 2003. Actually, it is 2023.
Now, here’s Stephanie!
Now, the numbers…
| Manufacturer | Head |
|---|---|
| Racquet Model | Head Gravity Tour 98 PreRelease |
| Reference Tension | 56 |
| String | PEEK 7710 |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 49 |
| String Bed Stiffness -FlexFour | 57.7 |
| Strig Bed Stiffness - SBS | 43.7 |
| String Bed Stiffness - ERT | 33Kg/Cm^ |
| Racquet Flex, RDC | 57 |
| Racquet Flex, FlexFour | 44.8 |
| Racquet - In Plane Stiffness | 373.1 |
| Weight, Grams | 327 |
| Weight, Ounces | 11.53 |
| Balance, mm | 325 |
| Balance, Inch | 12.80 |
| Length, Cm | 68.6 |
| Length, Inch | 27.008 |
| Head Width | 9.827 |
| Head Length | 12.724 |
| Head Area, cm2 | 633.6 |
| Head Area, Sq. Inch | 98.2 |
| Beam Height @ Grip, mm | 21.0 |
| Beam Height @ Mid, mm | 22.0 |
| Beam Height @ Tip | 22.0 |
| Beam Width @ Grip, mm | 10.7 |
| Beam Width @ Throat, mm | 11.3 |
| Beam Width @ Mid, mm | 10.5 |
| Beam Width @ Tip, mm | 12.1 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio | .650 |
| Main String Grid Inch/mm | 7.50/190.5mm |
| Cross String Grid Inch/mm | 10.38/263.6 |
| Density (% of head filled with string) | .785 |
| Average Cross String Space | .546 |
| Average Main String Space | .464 |
| Dynamic Tension, Kp, ERT | 33 |
| Dynamic Tension, Lbs/in | 184.57 |
| First Moment, Nm | ,818 |
| Polar Moment | 335 |
| Torsional Stability | 14 |
| Swing Weight, Kg/cm2 | 321 |
| Swing Weight, Ounces | 11.32 |
| Swing Weight Calculated | 345.4 |
| Power, RDC | 51 |
| Control, RDC | 47 |
| Manueverability, RDC | 73 |
| Power, Calculated | 1814.8 |
| Head Points | 5.83 |
| Head Weight, % | 47.3% |
| Center of Percussion | 21.1 |
| Dwell Time, ms | 6.69 |
| Efective Stiffness - lbs | 26.3 |
| K, Lb/In | 157.05 |
| Recoil Weight | 157.80 |
| Twist Weight | 236.02 |
| End Weight | 132.2 |
| Tip Weight | 192.1 |
| 9 O'Clock | 91.6 |
| 3 O'Clock | 90.8 |
| Butt End | 143.1 |
| COF, Main | .378 |
| COF, Cross | .386 |
Head Gravity 2023 Team , MP, and Pro Comparison
Moving between several reviews to compare racquets is tiresome, for sure, and inefficient!
We don’t want you to be tired or inefficient, so we include our Three Racquet Comp Data for the new Head Gravity 2023 models!
A word about “dwell time”. To get a more accurate view of the racquet we have elimiiated the player from the “slow” dwell time. This allows us to see excatly what happens when the ball is “dropped” on the string bed without any external force (your swing)!
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.
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!
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.
Racquet Quest, LLC
