Zyex-based string families for racquetball

February 23, 2016

Ashaway, RI – While nylon strings have long dominated racquetball courts, recent years have seen a decided increase in the use of other specialty polymers, principally a polyetheretherketone polymer — better know as PEEK — marketed under the brand name Zyex. Ashaway Racket Strings currently offers two families of Zyex®-based strings for racquetball, UltraKill® and PowerKill®, both of which feature the high dynamic stiffness and superior tension holding characteristics of this space age polymer.

“The property that makes Zyex so good for racquet strings is its low dynamic stiffness, which allows strings to stretch and recover more completely than other synthetic materials,” said Ashaway’s Steve Crandall. “This generates power with low impact shock (soft power). Zyex can also be made to have exceptionally low creep under continuous tension, allowing racquet strings to maintain tension and playability longer.”


Ashaway’s UltraKill family of racquetball strings offers players a full range of Zyex-enhanced playing characteristics, allowing them to choose the precise combination of power, durability and feel that is right for their game. Available in 17 and 18 gauge thicknesses, each UltraKill string is built on a specially constructed Zyex polymer core engineered to provide specific performance characteristics while maintaining tension for longer string life. Braided surfaces also maximize control and increase spin.

UltraKill 17 and 18 utilize multifilament cores produced with new generation Zyex filaments that are finer and even stronger than before, and provide superior feel, more power, and improved ball control. UltraKill 17 is designed to provide amateur and professional players with a strong durable string with both exceptional power and ball control.

UltraKill 18 combines the latest high tech Zyex materials with an innovative core construction technique to offer the thinnest, strongest, softest playing racquetball string on the market. According to Crandall, UltraKill 18 is designed for players who want to increase shot speed and control. “UltraKill 18 has more elasticity than its thicker gauge sibling. This increases both power and feel, as the ball “sits” on this string longer, also giving you more control over your shots.”

Ashaway’s most recent innovation with Zyex fibers is in the jacket or wear layer. “Jackets are designed to hold core packages together, increase abrasion resistance, and sometimes add surface texture to increase bite on the ball,” said Crandall. “However, when we wove Zyex fibers into jacket constructions, we found they enhanced performance characteristics as well.”

So good was this new construction that Ashaway trademarked it as PFT™ (Power Filament Technology) and built their new PowerKill family around it. The PFT jackets on the multifilament nylon core of PowerKill strings add power (soft power), improve tension holding, and increase string durability.

Ashaway’s PowerKill family includes PowerKill Pro and PowerKill 17. PowerKill Pro is a tough 16 gauge (1.30 mm) string designed for professional level racquetball players plagued by chronic string breakage. PowerKill 17 is a lighter 1.25 mm version of PowerKill Pro, and provides superior feel and ball control. It is designed for top-level racquetball players looking for superior power and tension stability.

Said Crandall, “We continue to experiment with Zyex and hope to offer even more performance options in the future. But for now, there are two Zyex choices for racquetball. If you like the feel of nylon, but would like more power and better tension holding, try a PowerKill string. If you like the power and feel of unbridled Zyex, go with an UltraKill model.”

Ashaway Racket Strings are made by Ashaway Line & Twine Mfg. Co., the only U.S. manufacturer of string for squash, tennis, racquetball, and badminton. Operated by the Crandall family since 1824, Ashaway has been making racquet strings since 1949, and is responsible for several important technical innovations. Ashaway has been the Official String of USA Racquetball for more than ten years, and is also the Official String of Professional Tennis Registry. Ashaway Line & Twine Mfg. Co. also makes braided products for medical and industrial applications. For more information visit Zyex is a registered trademark of Zyex Ltd.