Category Archives: IsoSpeed
Play Better Longer
For many years, we have been testing all racquets for string bed stiffness, effective stiffness, flexural stiffness, in-plane stiffness, and about any other stiffness you can imagine.
Throughout this process, we were also testing the strings for power potential, creep, string-on-string friction, and linearity.
Linearity is a significant property of string; however, it does not get the attention we believe it deserves. So, this little post will begin to change that. We will start with some images and explain what we see in them.
String Behavior
Four different string materials are represented here from left to right:
- RPM Blast
- IsoSpeed Polypropylene Composite
- Babolat VS Touch Natrual Gut
- Ashaway MonoGut ZX Polyether ether ketone (PEEK)
The entire chart is important, but the real property we are interested in for this post is “linearity”.
- Linearity is how straight the plot is from the beginning to failure.
- Failure is the vertical line associated with each string material.
A glance will show MonoGut ZX with the longest linear track, however, Babolat VS Touch is the very “straightest”, followed by IsoSpeed and RPM Blast.
OK, but why do we care? We care because when we say a string will play better longer, it is based on the linearity which is the property directly related to consistency.
Better predictability = better performance
Players perceive predictability more than raw stiffness.
A string that ages predictably plays better longer, even if it’s not the softest or most powerful.
That’s it!
Now all we need to do is quantify “better”.
I will leave that up to you.
Is this a cost effective alternative?
Everyone loves natural gut but not everyone loves the price, even though it is very much worth it!
You may think ” I will just use synthetic gut it must be about as good”. Nope, not even close. However there is string that may be close enough to consider as an alternative.
One such string is IsoSpeed Professional. Because we know “a picture is worth a thousand words” here is a picture:
IsoSpeed v VS Touch
If you are serious about playing tennis at a high level for a long time please consider an alternative to a string that does not help that effort.
This is one, however there are others that we will highlight in future posts.
Yonex V-Core 100
The Yonex V-Core is a great opportunity to review the racquet with IsoSpeed Professional 17 gauge string. If you know anything about the racquet you will know it is a great platform for many player types.
But what about IsoSpeed strings? These strings, and there are a series of them, are unusual in the material and construction, therefore not very well considered!
The string is polypropylene fibers bonded together then stretched and packaged on a stiff molded reel to retain some of the stretching.
If you have seen our previous review on our Questron data you will notice some similarity to natural gut.
| Manufacturer | Yonex |
|---|---|
| Racquet Model | Yonex V-Core 100 |
| Reference Tension | 55 |
| String | IsoSpeed Professional 17 |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 41 |
| String Bed Stiffness -FlexFour | 53 |
| String Bed Stiffness SBS | 48.6 |
| String Bed Stiffness - ERT | 31 Kg/Cm^ |
| Racquet Flex, RDC | 66 |
| Racquet Flex, FlexFour | 48.6 |
| Racquet - In Plane Stiffness | 423.7 lbs/In |
| Weight, Grams | 321 |
| Weight, Ounces | 11.32 |
| Balance, mm | 324 |
| Balance, Inch | 12.76 |
| Length, Cm | 68.8 |
| Length, Inch | 27.08 |
| Head Width | 9.87 |
| Head Length | 12.82 |
| Head Area, cm2 | 641.3 |
| Head Area, Sq. Inch | 99.4 |
| Beam Height @ Grip, mm | 22 |
| Beam Height @ Mid, mm | 25.6 |
| Beam Height @ Tip | 25.5 |
| Beam Width @ Grip, mm | 16.3 |
| Beam Width @ Throat, mm | 15.2 |
| Beam Width @ Mid, mm | 10.3 |
| Beam Width @ Tip, mm | 11.6 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio | .649 |
| Main String Grid Inch/mm | 7.50 / 190.5 |
| Cross String Grid Inch/mm | 10.15 / 257.8 |
| Density (% of head filled with string) | .747 |
| Average Cross String Space | .529 |
| Average Main String Space | .461 |
| Dynamic Tension, Kp, ERT | 31 |
| Dynamic Tension, Lbs/in | 173.4 |
| First Moment, Nm | .800 |
| Polar Moment | 328 |
| Torsional Stability | 15 |
| Swing Weight, Kg/cm2 | 313.0 Kg/Cm^ |
| Swing Weight, Ounces | 11.094 |
| Swing Weight Calculated | 337.0 |
| Power, RDC | 58 |
| Control, RDC | 41 |
| Manueverability, RDC | 78 |
| Power, Calculated | 2073.9 |
| Head Points | 5.98 |
| Head Weight, % | 47.2% |
| Center of Percussion | 21.1 |
| Dwell Time, ms | 7.31 |
| Efective Stiffness - lbs | 25.3 |
| K, Lb/In | 131.4 |
| Recoil Weight | 154.2 |
| Twist Weight | 233.8 |
| End Weight | 130.7 |
| Tip Weight | 188.4 |
| 9 O'Clock | 90.5 |
| 3 O'Clock | 89.4 |
| Butt End | 140.2 |
| COF, Main | .392 |
| COF, Cross | .321 |
Racquet Quest, LLC
