Category Archives: Inspiration
Three Important Things
When dealing with tennis racquets, there are many significant performance parameters. We are going to list our three (3) most important ones:
- Swing Weight
- Overall Weight
- Effective Stiffness
These particular parameters are based on machine testing, physics, and experience.
- Swing Weight: we refer to this as a dynamic weight, meaning how heavy or light the racquet feels during the swing to the ball.
- Overall Weight: This is normally considered to be the weight found on a scale, electronic, or balance. Weight is your friend if properly associated with your capabilities and stature.
- Effective Stiffness: is a calculable and measurable stiffness of the ball hitting the string as you are holding the racquet and hitting a ball.
Why is it Important?:
- Swing Weight: contributes to power and stability, which contributes to control. A higher swing weight of, say, 320 to 340 will handle most incoming balls with ease. Swing weights of 300 to 319 will be easier to maneuver and require a little more energy from the player to handle aggressive incoming balls.
- Overall Weight: contributes to ease of movement and long play time and must be associated with the stature and style of the player. The heavier racquet will provide more power with less energy expended by the player.
- Effective Stiffness: this is a metric we use to ensure the racquet is within the stiffness range needed by the player. For example, if you come into the World Headquarters of Racquet Quest for the first time with your current racquet and the strings are intact, we can determine the effective stiffness and, based on your satisfaction with the current playability, arrive at a corresponding effective stiffness…not on a reference tension. A range of 24 to 30 pounds is acceptable. Anything over 30 becomes quite stiff and should be avoided by most players.
If you look at our racquet reviews, you will see a lot more than three (3) performance parameters! We believe they are all important, but players should understand the three (3) described here.
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 |
Strings are made to Work (and wear out)!
If tennis strings are doing what they should, they will wear out!
What happens between the time strings are installed and the time they need to be replaced?
- Strings are under tension (stress)
- Strings are subject to fatigue due to hits
- Strings are subject to frictional notching due to sliding
- Strings are elastic but will lose tension
- Strings break
All of the above actions are subject to many variables, of course!
- String Bed Pattern (16×19, 18×20,,,)
- Sring Bed Size (90, 95, 98, 100, 110… square inch)
- Racquet head speed
- Racquet head angle
- String wear
- Environment (wet, dry, hot, cold…)
What does this actually look like, though?
This will give an idea of what a really good wear pattern will look like
-
- COP View
-
- Full String Bed
after about ten (10) weeks of use. This is a 17-gauge multifilament in a 98-square-inch head size at a reference tension of 55 pounds (24.9kg).
In fact, the COF (coefficient of friction) is greater than when the string was fresh!
COF_ M: 23%, X: 31.5% greater! This means if you have the nerve (no fear of breaking string), you can continue to play and enjoy the grabbing of the ball by the tiny tentacles that get caught in the ball fuzz.
This will not last forever, though!
COP View
This wear pattern is typical of high-quality multifilament strings.
When making a string selection, think about how long you want the string to perform well, not necessarily how long it will stay in your racquet.
If you need some ideas, go to our String Frequency Calculator. This will give you some high performance stringing cycle recommendations.
Have fun … and use up your string!
T-Shirts with a Message!
Just in case you can not make it to Racquet Quest’s World Headquarters, we are posting our T-shirt loop here so you all can see it!
If you can’t make it to the World Headquarters you can pick up your “T-Shirts with a Message” here!
Racquet Quest, LLC
