String Theory: The Science of Recurve Bowstrings

brown and white bow tie on green grass field

For recurve archers, the bowstring is a crucial piece of equipment that can significantly impact performance. Selecting the right bowstring involves understanding the science behind how bowstring materials, construction, and maintenance affect efficiency, accuracy, and the shooting experience. This article will explore the technical aspects of recurve bowstrings to provide archers with the knowledge to optimize their gear.

A Brief History of Bowstring Materials

For centuries, bowstrings were made from natural materials like hemp, linen, silk, rawhide, and animal sinew or guts. These traditional materials provided the combination of strength, stretch, and smoothness needed for archery. However, they also had limitations in performance and consistency.

The 20th century saw the introduction of synthetic bowstring materials that offered superior durability, weather-resistance, and performance. Nylon was one of the first synthetics used for bowstrings beginning in the 1930s. While nylon excelled in strength and stability, it was also known for excessive stretch and creep.

In the 1970s, Kevlar replaced nylon as the preferred bowstring material due to its vastly reduced stretch. However, Kevlar tends to be rough on the fingers. This led to the development of modern bowstring materials that blend the benefits of different fibers.

Common Bowstring Materials

Today’s recurve bowstrings are typically made using high-performance polyethylene fibers like Dyneema or Spectra. These fibers are braided or twisted into strands to create the bowstring. Other materials are also sometimes blended in to achieve desired characteristics.

Dyneema

This gel-spun polyethylene fiber boasts exceptional strength-to-weight qualities. Dyneema has very low stretch, is durable and stable, and resists abrasion well. It also maintains good shootability with smoothness and consistency. The leading brand of Dyneema fiber is SK75.

Spectra

Similar to Dyneema, Spectra is an ultra-strong polyethylene fiber. It is known for an extremely smooth feel and surface texture that provides excellent release off the fingers. Spectra also minimizes “fuzzing” or fraying that can occur on other materials. It is slightly more stretchy than Dyneema.

Vectran

Vectran is a liquid crystal polymer that is sometimes blended with Dyneema or Spectra to further enhance stability and creep resistance. However, Vectran is more susceptible to abrasion and durability issues.

Dacron

Dacron polyester is rarely used in modern recurve strings but remains popular with traditional bows. It has good abrasion resistance but high stretch and creep. Dacron provides a smooth draw that is forgiving for beginners.

String Construction

Beyond materials, the construction of a bowstring also influences its characteristics and performance. These elements all factor into the final product:

  • Strand count – More strands mean increased durability and stability but also extra weight. Typical strand counts are 16-20 for mid-weight bows and 20-24 for heavier bows.
  • Strand thickness – Thinner strands can improve stability and reduce peep rotation but may compromise durability. Common strand diameters range from .007” to .014”.
  • String weight – Heavier bowstrings store more kinetic energy to propel arrows. But excess weight strains the limbs and can slow arrow speed. Avoiding overly thick strands maintains a good balance.
  • String diameter – Related to weight, larger diameter strings have more surface contact with the bow during shooting. Smaller diameters around .090” to .100” minimize friction.
  • Twist rate – Adding more twists evens out tension between strands but can make tuning more difficult. Twist rates vary greatly between archers, bows, and string materials.
  • Serving – End loops and center servings protect the string at contact points and enable nock fit. The serving material and thickness must match the string diameter.

Tuning and Maintenance

To sustain top performance, bowstrings require proper tuning and regular maintenance:

  • Closely monitor strings for any signs of wear and tear such as fraying or peep rotation issues. These indicate it is time to replace the string.
  • Apply string wax every dozen shots or so, focusing on the center serving where the arrow nock contacts the string. Wax protects strands and increases smoothness.
  • Equalize tension between stretched and relaxed strands by removing all twists before installation on the bow, allowing strands to settle for 24 hours, then adding twists back.
  • Avoid over-twisting the string as this can lead to increased creep and tuning difficulties. Adjust twist rate gradually when tuning.
  • Check that center serving fits arrow nocks snugly but allows smooth release.Mismatched serving or nock fit will detrimentally affect arrow flight.
  • Use a bow square to precisely set nocking point location based on optimal arrow flight and fletching clearance.
  • Stretch strings overnight before first installing on a bow to remove initial relaxation of strands.Pre-stretching reduces future creep.

How Bowstring Properties Influence Shootability

For recurve archers, the subjective “feel” of shooting is crucial. The physical properties of the bowstring greatly affect the smoothness, release, vibration, and overall shootability from the archer’s perspective. These aspects of engineering strings are less tangible but still important:

Stiffness/Elasticity

Bows store energy as the string is drawn and then transfer it to the arrow upon release. An ideal string will maintain enough stiffness to efficiently return energy back into the arrow while still flexing to modulate vibrations. Synthetic materials can be engineered with precise stiffness levels.

Surface Texture/Smoothness

Minimal friction between the string and fingers improves comfort while shooting and enables a clean release for undisturbed arrow flight. Materials like Spectra provide an ultra-smooth texture. The addition of string wax also enhances slickness.

Mass/Weight

Heavier bowstrings exhibit higher inertia and momentum to propel arrows with added force. But excessive mass strains limbs without significantly boosting speed. Finding the ideal balance of mass/weight benefits both the bow and archer.

Creep/Stretch

Natural lengthening of the string over repeated shooting cycles is known as creep or stretch. Excessive creep alters brace height which requires constant re-tuning. Synthetic materials with minimal creep maintain consistency and save time.

Fuzzing/Abrasion

Surface fibers separating from the string leads to fuzzing and roughness over time. Materials such as Dyneema are more prone to fuzzing and require special coatings or treatment to reduce abrasion.

Vibration & Sound

Bows naturally resonate upon shooting. Materials and construction that quickly absorb these vibrations limit noise as well as hand shock felt by the archer. Multi-strand strings with some stretch are the most effective at reducing vibration.

By understanding how these physical characteristics translate into actual shooting experience, archers can select optimal bowstrings for their preferences and shooting style.

Choosing the Best String Material

With all of the available materials and factors to weigh, deciding on the ideal bowstring can pose a challenge. While personal preference plays a large role, here are some general guidelines:

  • For minimal creep and maximum stability, Dyneema SK75 is an excellent all-around choice. It provides good durability and smoothness as well.
  • Spectra offers the smoothest feel, best release, and least fuzzing of any material. It works well for dedicated target archers.
  • Archers who value light weight and speed should lean towards thinner Dyneema strings with minimal strand counts.
  • Blends of Dyneema and Vectran optimize stability for archers who want to minimize tuning adjustments and creep over time.
  • Those new to string making may want to start with easy-to-work Dacron before moving to synthetics which require more precision.
  • Evaluating your current bowstring for wear, fuzzing, serving separation, creep, and notable vibrations can indicate where improvements may be needed.
  • Seek input from fellow archers regarding strings they have tested and found optimal for equipment and shooting style similar to yours.

Staying up-to-date on new materials and technology allows you to experiment with custom strings that maximize both performance and your unique preferences. Don’t be afraid to try different options and find what works best for you.

Bowstring Brands

In addition to selecting a particular string material, choosing a quality brand ensures you get a product that is expertly crafted to precise specifications for top performance. Here are some of the most trusted names in recurve bowstrings:

BCY

The flagship brand of Brownell Company, BCY offers a wide selection of string materials including Dyneema, Spectra, and Dacron. They also sell Mercury, a thin Dyneema string designed specifically for recurves. BCY strings have an excellent reputation for quality and consistency.

Angel

Specializing in strings for recurve and traditional bows, Angel provides all-DyneemaMajesty and DynaFLIGHT 97 strings purpose-built for accuracy and stability. Based in Japan, Angel’s experience dates back to 1954.

60X Custom Strings

This devoted string maker is popular among competitive archers and offers fully customized recurve strings. 60X uses premium BCY materials and individually inspects each string before shipping.

Stone Mountain Strings

Stone Mountain handcrafts recurve and longbow strings from BCY fibers combined with their proprietary ArrowCoat finish to reduce abrasion and wax buildup.

Nemesis Bow Strings

Utilizing high-grade Dyneema and Gore fibers, Nemesis strings are pre-stretched and made in a climate-controlled facility for unsurpassed quality control and consistency.

Finding a brand that aligns with your goals and budget will ensure you get a long-lasting recurve bowstring optimized for efficiency and feel. Don’t settle for generic factory strings when custom options are available.

Conclusion

For recurve archers, every piece of equipment plays a role in performance, and the bowstring is no exception. Selecting the optimal design and material requires balancing specialized engineering properties with individual shooting preferences. By gaining a deeper understanding of the science and construction behind modern bowstrings, archers can make informed decisions in upgrading this vital gear component. With the right bowstring, archers can realize the maximum potential of both their equipment and shooting abilities.

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