Cross String Tension…Yikes!
Cross-string tensions, or actually reference tensions, are the topic of this brief post.
First, every tennis racquet has a “natural” ratio, that is, if the reference tension (and machine setting ) is 50 for both the main string and cross string when the racquet is removed from the stringing machine, the tensions remaining will be in the area of around 50 for the mains and 37 for the cross.
The resultant tension is the natural ratio of that specific racquet.
The issue with changing cross-string tension either higher or lower than the main is that the racquet has changed shape. That is why we test for In-Plane stiffness for every racquet. The higher the In-Plane stiffness, the higher the cross-string tension will remain upon removal from the machine.
If the racquet has very low In-Plane stiffness, it has expanded in width with only the main string installed, so the cross strings need to pull the racquet back into a better (hopefully original) shape.
So, when deciding how much variation you want between the main and cross strings, please consider the racquet! In most cases, we suggest using the same string tension setting for both the main and the cross, since the cross string tension will naturally be lower.
Our True Tension Professional stringing equipment supports the racquet in such a way that we install the main string and cross string at the natural ratio, so the racquet does not change shape and the string bed is consistent.
If you are curious about In-Plane stiffness for a specific tennis racquet, please leave a comment below.
Launch Angle…what is it and how do we use it?
In the simplest terms, “launch angle” is the angle the ball leaves the tennis racquet relative to the court. That does seem simple enough, but how do we, or can we, contribute to it?
We are getting more and more calls asking what to do to reduce launch angle, as the game is changing to a flatter style, which generates a little more energy.
- Racquet Trajectory plays an important role in launch angle. That is why we hear “low to high” so often.
- A flat stroke can generate more ball speed but less spin.
- String Bed Stiffness is another property that contributes to launch angle.
- A stiffer string bed can reduce launch angle.
Many, many factors contribute to this, so we think this way:
As a player, you do not want to change too many things about your stroke; you want the racquet to do the changing for you!
OK, then! The first, and maybe the only thing you would do is pick up a racquet with an 18 x 19 string pattern! In most cases, you do not even need to change your reference tension(s).
We believe the 18 x 19 pattern is slightly more compatible than an 18 x 20, but either would work to help keep your launch angle under your control!
A Wilson RF 01 300 Extended
We want to share the specifications of an extended (70.0mm/27.559) Wilson RF 01 300.
The lengthening process involves removing the staples holding the butt on, which needs to be done carefully for the integrity of the foam pallet, before proceeding with the next steps.
Any time the butt cap comes off a racquet, the first step is to fill the open shaft with a stopper, preferably cotton, to the desired depth for fitting or protection. If the racquet is “foamed” some of it is removed.
Numerous small details go into the extension we design and print, so we will not go into all of those right now.
The area that will accept the extension is filled with a new two (2) part epoxy made by Starbond. This epoxy is nearly fully cured after several minutes; however, we prefer to let it cure overnight before proceeding with any other work.
After the curing cycle, the butt cap is installed. We do not use staples in most cases, only a chemical adhesive. Staples can easily damage the original foam pallet and the extension if the location is not ideal.
If you make it to the end of this data table, you will find some comparison data. This data is a glance at what has changed from the original 27-inch length. This is a specific racquet, so your specifications, if extended, may differ.
This is enough small talk, so let’s take a look at the results of the extension.
| Manufacturer | Wilson |
|---|---|
| Racquet Model | RF 01 300 Long |
| Reference Tension | 56 |
| String | Wilson Duramax NXT |
| Machine Used | Baiardo |
| String Bed Stiffness - RDC | 47 |
| String Bed Stiffness -FlexFour | 57 |
| Strig Bed Stiffness - SBS | 50.4 |
| String Bed Stiffness - ERT | 32 |
| Racquet Flex, RDC | 62 |
| Racquet Flex, FlexFour | 50.4 |
| Racquet - In Plane Stiffness | 450.6 |
| Weight, Grams | 355 |
| Weight, Ounces | 12.52 |
| Balance, mm | 314 |
| Balance, Inch | 12.36 |
| Length, Cm | 70 |
| Length, Inch | 27.559 |
| Head Width | 9.70 |
| Head Length | 12.80 |
| Head Area, cm2 | 629.1 |
| Head Area, Sq. Inch | 97.5 |
| Beam Height @ Grip, mm | 23 |
| Beam Height @ Mid, mm | 23 |
| Beam Height @ Tip, mm | 23 |
| Beam Width @ Grip, mm | 11.5 |
| Beam Width @ Throat, mm | 12 |
| Beam Width @ Mid, mm | 12 |
| Beam Width @ Tip, mm | 12 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio | .639 |
| Main String Grid Inch/mm | 7.42/188.5 |
| Cross String Grid Inch/mm | 10.56/268.2 |
| Density (% of head filled with string) | .804 |
| Average Cross String Space | .556 |
| Average Main String Space | .464 |
| Dynamic Tension, Kp, ERT | 32 |
| Dynamic Tension, Lbs/in | 178.9 |
| First Moment, Nm | .850 |
| Polar Moment | 356 |
| Torsional Stability | 17 |
| Swing Weight, Kg/cm^2 | 339 |
| Swing Weight, Ounces | 11.96 |
| Swing Weight Calculated | 350.0 |
| Power, RDC | 55 |
| Control, RDC | 41 |
| Manueverability, RDC | 61 |
| Power, Calculated | 2151.9 |
| Head Points | 11.34 |
| Head Weight, % | 44.9 |
| Center of Percussion | 21.5 |
| Dwell Time, ms | 6.83 |
| Efective Stiffness - lbs | 26.7 |
| K, Lb/In | 150.6 |
| Recoil Weight | 178.85 |
| Twist Weight | 250.25 |
| End Weight | 153.9 |
| Tip Weight | 200.4 |
| 9 O'Clock | 95.7 |
| 3 O'Clock | 94.4 |
| Butt End | 163.6 |
| COF, Main | .304 |
| COF, Cross | .386 |
| Property | Original | Extended | Change % |
|---|---|---|---|
| Overall Weight | 319 | 355 | 10.1 |
| Swing Weight | 310 | 339 | 8.5 |
| Length | 27.0 | 27.55 | 2.0 |
| Power Calculaton | 1892.8 | 2151.9 | 12.0 |
| Recoil Weight | 149.4 | 178.8 | 16.4 |
| Twist Weight | 224.87 | 250.2 | 10.1 |
Gifting for a Tennis Player?
Gift Card
Most of you who have tennis players in the family know how difficult it can be to find the right item at the right time!
A stress-free answer to that difficulty is a Racquet Quest Gift Card.
Let your player make all the decisions while you relax!
Racquet Quest, LLC
