Category Archives: String Patterns
Right here…Right now! Squared
Head Squared…Here!
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.
Nordic Dots
A friend is visiting from the UK and was kind enough to bring along a Nordic Dots Model 99 tennis racquet.
Nordicdots 99
We don’t see many of these here. I was delighted to have the opportunity to go through the specs!
The first thing you will notice is the incredible gloss black finish! The only adornment is the silver name, Noricdots, and model 99… that’s all!
Next comes the head shape, which is not dramatically different but is notable with the broad top portion.
Then the string pattern is 16 x 20 with a twist (little). The pattern is really dense through the 13th cross string, then begins to open up as it nears the throat
The expanded string spacing around the periphery is not unusual, but the density at the upper portion is “tight”.
This model 99 is foam-filled and uses a standard foam grip pallet. The butt cap has an access door for those who want to mess around back there!
Model 99
Nordicdots
| Manufacturer | Nordicdots |
|---|---|
| Racquet Model | Model 99 |
| Reference Tension | 46 |
| String | MonoGut ZX Pro Black |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 43 |
| String Bed Stiffness -FlexFour | 52.9 |
| Strig Bed Stiffness - SBS | 44.7 |
| String Bed Stiffness - ERT | 30 |
| Racquet Flex, RDC | 62 |
| Racquet Flex, FlexFour | 38.3 |
| Racquet - In Plane Stiffness | 423 |
| Weight, Grams | 325 |
| Weight, Ounces | 11.46 |
| Balance, mm | 323 |
| Balance, Inch | 12.72 |
| Length, Cm | 68.6 |
| Length, Inch | 27.0 |
| Head Width | 9.59 |
| Head Length | 12.904 |
| Head Area, cm2 | 614.8 |
| Head Area, Sq. Inch | 95.3 |
| Beam Height @ Grip, mm | 23.8 |
| Beam Height @ Mid, mm | 23.2 |
| Beam Height @ Tip | 23.2 |
| Beam Width @ Grip, mm | 11.5 |
| Beam Width @ Throat, mm | 10.5 |
| Beam Width @ Mid, mm | 10.5 |
| Beam Width @ Tip, mm | 12.9 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 20 |
| Ratio | .583 |
| Main String Grid Inch/mm | 7.31/185.6 |
| Cross String Grid Inch/mm | 9.93/252.2 |
| Density (% of head filled with string) | .762 |
| Average Cross String Space | .497 |
| Average Main String Space | .457 |
| Dynamic Tension, Kp, ERT | 30 |
| Dynamic Tension, Lbs/in | 167.8 |
| First Moment, Nm | .807 |
| Polar Moment | 337 |
| Torsional Stability | 16 |
| Swing Weight, Kg/cm^2 | 321 |
| Swing Weight, Ounces | 11.32 |
| Swing Weight Calculated | 339.1 |
| Power, RDC | 51 |
| Control, RDC | 47 |
| Manueverability, RDC | 73 |
| Power, Calculated | 1915.4 |
| Head Points | 6.30 |
| Head Weight, % | 47% |
| Center of Percussion | 21.37 |
| Dwell Time, ms | 7.14 |
| Efective Stiffness - lbs | 25.39 |
| K, Lb/In | 137.82 |
| Recoil Weight | 161.7 |
| Twist Weight | 216.1 |
| End Weight | 132.7 |
| Tip Weight | 191.2 |
| 9 O'Clock | 90.6 |
| 3 O'Clock | 90.6 |
| Butt End | 143.5 |
| COF, Main | .358 |
| COF, Cross | .311 |
You can use this, not that!
Racquet Quest is constructing a “dynamic stiffness test” device to perform dynamic testing of tennis racquet string beds.
Why? So we can determine the string bed stiffness that will suit and even enhance performance on the court.
String bed stiffness is a significant number, and we take it in four (4) ways, but they are “static” methods. Static in the sense that the load is applied rather slowly. String bed stiffness is significant because players may not hit the ball slowly!
Our Questron pulls loads all the way to failure on all sorts of strings, but it is one (1) string, not a bunch like a strung racquet; therefore, our dynamic device will hit the string bed with a variable force, associated with a “harder” ball strike!
It is essential to understand when a string bed may be too harsh or too compliant for a player by learning the dynamic stiffness of various tennis racquets, string patterns, and strings.
So, use this, not that!
We take this data now, and it makes much sense; however, our new device will be more precise.
Stay tuned!
Racquet Quest, LLC
