Category Archives: PEEK
Head Auxetic 2 Radical Pro 2025
The Radical Pro represents the pinnacle of a player’s racquet. So, this review is based on our desire to see how much power we can squeeze out of it through string bed stiffness.
The following specifications explain why this racquet’s natural properties make it a powerhouse.
This 98-square-inch racquet packs a powerful 339-gram weight with a very easy-to-handle 331 swing weight!
With this racquet, you will not be pushed around by big hitters.
As tested, this racquet has a stiffness rating of 66, which is moderately high. However, with an effective stiffness of 27.1, it is well within the range of any player who can benefit from the other performance factors.
As you can tell from the picture, the racquet is ORANGE. These pictures are the skills of Bobby Diviliansky, a high school student who just happened to stop at the World Headquarters! His brother Ryan is a client, so he had a reason to be here.
| Manufacturer | Head |
|---|---|
| Racquet Model | Head PT57A2 Auxetic Coat - No Grip Pallet |
| Reference Tension | |
| String | |
| Machine Used | |
| String Bed Stiffness - RDC | |
| String Bed Stiffness -FlexFour | |
| Strig Bed Stiffness - SBS | |
| String Bed Stiffness - ERT | |
| Racquet Flex, RDC,No Pallet | 62 |
| Racquet Flex, FlexFour, No Pallet | 57 |
| Racquet - In Plane Stiffness | 462.2 |
| Weight, Grams | 255.6 |
| Weight, Ounces | 9.016 |
| Balance, mm | 354 |
| Balance, Inch | 13.94 |
| Length, Cm | 68.2 |
| Length, Inch | 26.850 |
| Head Width | 9.437 |
| Head Length | 12.748 |
| Head Area, cm^2 | 611.3 |
| Head Area, Sq. Inch | 94.75 |
| Beam Height @ Grip, mm | 21.1 |
| Beam Height @ Mid, mm | 20.3 |
| Beam Height @ Tip | 20.3 |
| Beam Width @ Grip, mm | 11.0 |
| Beam Width @ Throat, mm | 11.0 |
| Beam Width @ Mid, mm | 11.7 |
| Beam Width @ Tip, mm | 11.5 |
| Number of Main Strings | 18 |
| Number of Cross Strings | 20 |
| Ratio | .634 |
| Main String Grid Inch/mm | 7.18/182.3 |
| Cross String Grid Inch/mm | 9.51/241.5 |
| Density (% of head filled with string) | |
| Average Cross String Space | |
| Average Main String Space | |
| Dynamic Tension, Kp, ERT | |
| Dynamic Tension, Lbs/in | |
| First Moment, Nm | |
| Polar Moment | |
| Torsional Stability | |
| Swing Weight, Kg/cm^2 | 285 |
| Swing Weight, Ounces | |
| Swing Weight Calculated | 318.5 |
| Power, RDC | |
| Control, RDC | |
| Manueverability, RDC | |
| Power, Calculated | |
| Head Points | |
| Head Weight, % | |
| Center of Percussion | |
| Dwell Time, ms | |
| Efective Stiffness - lbs | |
| K, Lb/In | |
| Recoil Weight | |
| Twist Weight | |
| End Weight | 81.2 |
| Tip Weight | 177.6 |
| 9 O'Clock | 87.2 |
| 3 O'Clock | 87.9 |
| Butt End | 88.1 |
| COF, Main | |
| COF, Cross | |
So, what’s the big difference?
For nearly twenty years (20) years, we have been using PEEK for high performance tennis strings. Ashaway has been using PEEK longer than we have under MonoGut ZX and ZX Pro (thinner) models.
“The significant property differences between 1.25mm polyester and 1.25mm polyetheretherketone (PEEK) are based on their chemical composition, mechanical strength, thermal resistance, and durability. Here’s a comparison:
- Chemical Composition
- Polyester: A polymer made of ester functional groups commonly used in textiles, films, and some industrial applications.
- Polyetheretherketone (PEEK): A high-performance engineering thermoplastic with ether and ketone groups, known for its superior mechanical and thermal properties.
- Mechanical Properties
| Property | 1.25mm Polyester | 1.25mm PEEK |
| Tensile Strength | Lower (~50-100 MPa) | Much higher (~90-120 MPa) |
| Elastic Modulus | ~2-4 GPa | ~3.6-4.0 GPa |
| Toughness | Flexible, lower toughness | High toughness, impact-resistant |
| Abrasion Resistance | Moderate | Very high |
- Thermal Properties
| Property | 1.25mm Polyester | 1.25mm PEEK |
| Melting Point | ~250°C | ~343°C |
| Glass Transition | ~70°C | ~143°C |
| Thermal Stability | Moderate | Excellent |
PEEK can withstand much higher temperatures than polyester, making it ideal for high-heat applications.
- Chemical Resistance
- Polyester: Moderate resistance to chemicals but degrades in strong acids and alkalis.
- PEEK: Excellent chemical resistance, even to strong acids, bases, and solvents.
- Electrical Properties
- Polyester: Good dielectric properties but lower breakdown strength.
- PEEK: Exceptional electrical insulation properties, making it suitable for high-performance applications.
- Water Absorption & Durability
- Polyester: Absorbs some moisture, reducing strength over time.
- PEEK: Extremely low water absorption, maintaining strength and dimensional stability.
- Applications
- Polyester: Used in textiles, packaging, and some low-load industrial applications.
- PEEK: Used in aerospace, medical implants, and high-performance engineering applications.
Conclusion
If you’re looking for high strength, thermal resistance, and durability, PEEK is far superior to polyester. However, polyester is more cost-effective and widely used in consumer applications. The choice depends on the required application and performance needs.”
Head Auxetic 2 Radical MP 2025
The Head Radical MP has always been a popular racquet for many reasons, and we believe this series will be no different and maybe a little more popular…who doesn’t like Orange?
This is a true performance racquet for the unafraid!
Head Radical MP 202
The MP (mid-plus) model is a 98-square-inch head racquet with a very reasonable stiffness. It provides considerable control with as much power as needed.
As you look at the following specifications, you may notice the swing weight of 310kg/cm^2. At first, it may seem a little timid. The good news is that the property can be changed to suit your current or next-level game.
This racquet can stay with you for as long as you want. It won’t need to be changed as your game changes.
| Manufacturer | Head |
|---|---|
| Racquet Model | Head Auxetic 2 Radical MP 2025 |
| Reference Tension | 56 |
| String | MonoGut ZX Pro |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 52 |
| String Bed Stiffness -FlexFour | 59.5 |
| Strig Bed Stiffness - SBS | 35 |
| String Bed Stiffness - ERT | 35 |
| Racquet Flex, RDC | 64 |
| Racquet Flex, FlexFour | 38.4 |
| Racquet - In Plane Stiffness | 469.9 |
| Weight, Grams | 320 |
| Weight, Ounces | 11.29 |
| Balance, mm | 328 |
| Balance, Inch | 12.91 |
| Length, Cm | 68.5 |
| Length, Inch | 26.968 |
| Head Width | 9.59 |
| Head Length | 12.79 |
| Head Area, cm2 | 621.3 |
| Head Area, Sq. Inch | 96.3 |
| Beam Height @ Grip, mm | 21 |
| Beam Height @ Mid, mm | 22 |
| Beam Height @ Tip | 20.5 |
| Beam Width @ Grip, mm | 12.5 |
| Beam Width @ Throat, mm | 11.8 |
| Beam Width @ Mid, mm | 12.7 |
| Beam Width @ Tip, mm | 12.9 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio | .632 |
| Main String Grid Inch/mm | 7.25/184.2 |
| Cross String Grid Inch/mm | 9.31/236.5 |
| Density (% of head filled with string) | .706 |
| Average Cross String Space | .493 |
| Average Main String Space | .453 |
| Dynamic Tension, Kp, ERT | 35 |
| Dynamic Tension, Lbs/in | 195.8 |
| First Moment, Nm | .810 |
| Polar Moment | 326 |
| Torsional Stability | 16 |
| Swing Weight, Kg/cm^2 | 310 |
| Swing Weight, Ounces | 10.93 |
| Swing Weight Calculated | 344.3 |
| Power, RDC | 49 |
| Control, RDC | 52 |
| Manueverability, RDC | 80 |
| Power, Calculated | 1910.5 |
| Head Points | 4.57 |
| Head Weight, % | 47.9% |
| Center of Percussion | 20.7 |
| Dwell Time, ms | 6.49 |
| Efective Stiffness - lbs | 28.7 |
| K, Lb/In | 166.7 |
| Recoil Weight | 145.9 |
| Twist Weight | 220.7 |
| End Weight | 126.3 |
| Tip Weight | 193.1 |
| 9 O'Clock | 91.2 |
| 3 O'Clock | 91.5 |
| Butt End | 137.4 |
| COF, Main | .416 |
| COF, Cross | .360 |
Head Auxetic 2 Radical Team 2025
By now, you have probably seen the latest Radical series, which is very hard to miss. If you haven’t seen them yet, here is a peek at the “orangiest” of all racquets! These racquets look great and are perfectly matched to the Radical branding.
This review is of the Head Auxetic 2 Radical Team 2025, the lightest of the series with a 102-square-inch head.
Head Radical Team
When examining the following specifications, pay attention to the racquet’s stiffness. This flex may mitigate power but will open up a great combination for a player looking to take more control of the game.
The string we chose for this racquet is Ashaway Dynamite Natural 17 gauge (the color is a bright green, not natural). The material is PEEK fibers with a rough braided outer jacket, presenting a lovely COF if you care about these things.
The Radical has always been a great performance racquet, and this 2025 series is no exception. Come by the World Headquarters, get a demo, and tell us what you think.
| Manufacturer | Head |
|---|---|
| Racquet Model | Head Auxetic 2 Radical Team 2025 |
| Reference Tension | 56 |
| String | Dynamite PEEK Multi |
| Machine Used | True Tension Pro |
| String Bed Stiffness - RDC | 45 |
| String Bed Stiffness -FlexFour | 57.7 |
| Strig Bed Stiffness - SBS | 34.0 |
| String Bed Stiffness - ERT | 32 |
| Racquet Flex, RDC | 60 |
| Racquet Flex, FlexFour | 34 |
| Racquet - In Plane Stiffness | 421.8 |
| Weight, Grams | 301 |
| Weight, Ounces | 10.62 |
| Balance, mm | 330 |
| Balance, Inch | 12.99 |
| Length, Cm | 68.6 |
| Length, Inch | 27.008 |
| Head Width | 9.83 |
| Head Length | 13.12 |
| Head Area, cm2 | 653.2 |
| Head Area, Sq. Inch | 101.3 |
| Beam Height @ Grip, mm | 22.5 |
| Beam Height @ Mid, mm | 24.7 |
| Beam Height @ Tip | 22.8 |
| Beam Width @ Grip, mm | 12./6 |
| Beam Width @ Throat, mm | 12.5 |
| Beam Width @ Mid, mm | 12.6 |
| Beam Width @ Tip, mm | 12.8 |
| Number of Main Strings | 16 |
| Number of Cross Strings | 19 |
| Ratio | .631 |
| Main String Grid Inch/mm | 7.25/184.2 |
| Cross String Grid Inch/mm | 9.69/246.1 |
| Density (% of head filled with string) | .671 |
| Average Cross String Space | .493 |
| Average Main String Space | .453 |
| Dynamic Tension, Kp, ERT | 32 |
| Dynamic Tension, Lbs/in | 178.9 |
| First Moment, Nm | .768 |
| Polar Moment | 316 |
| Torsional Stability | 15 |
| Swing Weight, Kg/cm2 | 300 |
| Swing Weight, Ounces | 10.58 |
| Swing Weight Calculated | 327.8 |
| Power, RDC | 43 |
| Control, RDC | 57 |
| Manueverability, RDC | 87 |
| Power, Calculated | 1840.7 |
| Head Points | 4.09 |
| Head Weight, % | 48.1% |
| Center of Percussion | 21.0 |
| Dwell Time, ms | 6.98 |
| Efective Stiffness - lbs | 25.7 |
| K, Lb/In | 144.2 |
| Recoil Weight | 142.9 |
| Twist Weight | 217.2 |
| End Weight | 116.3 |
| Tip Weight | 183.8 |
| 9 O'Clock | 85.4 |
| 3 O'Clock | 86.2 |
| Butt End | 128.8 |
| COF, Main | .494 |
| COF, Cross | .388 |
Racquet Quest, LLC
