Frequently Asked Questions

A row of Targets
BCY Tensile Testing Machine
Shown above: BCY Tensile Testing Machine

Frequently asked questions about bowstring and serving material are addressed here. Please understand that there is not always one exact answer. A lot depends on the type of bow, the string type, the string length, the draw weight, how the string is made, and - of course - the shooter's personal preferences. We are trying to give general guidelines. If you need more help, please Email

1. Question: What is creep compared to stretch?
Answer: Creep is non recoverable elongation, unlike stretch - which is recoverable elongation. Some elasticity is necessary. Creep is a problem. It can cause the bow to go out of tune and the peep to rotate. Creep can affect the draw weight and the draw length.

2. Question: Are there any bowstring materials that do not creep?
Answer: Yes - 452X®, X-99®, 450 Plus; with the correct number of strands. These are blends of Dyneema® and Vectran. Vectran has no creep at the tension created by normal bows; therefore these materials are normally 100% stable.

3. Question: If these products have no creep, why would anyone use anything else?
Answer: No reason not to on modern high powered compounds. These no creep materials are a blend of two fibers, usually Vectran and Dyneema®.  100% Dyneema® (HMPE) is often used on recurves and traditional bows where creep is less of an issue. Slightly faster arrow speed and high durability.

4. Question: What is the fastest string material that does not creep?
Answer: On most compound bows, we suggest 24/26 strands of X-99®. Many recurve shooters like 8125® which is 100% Dyneema®, shoots fast and has low creep.

5. Question: Is it a fact that the lower the number of strands, the faster the arrow?
Answer: Yes on most bows but not all, and with today's extremely strong materials, a lower number of strands can normally be used safely. Of course it is important to be sure that the center serving is built up to allow a good nock fit when the number of string strands is reduced. Note also that at a certain point not too far below the manufacturer's recommended number of strands, it is quite likely that the archer will notice an increase in vibration directly after release because there is not enough mass in the string to absorb the "elastic energy" that occurs when the arrow is released.

Note that HMPE products like Dyneema® and Spectra are prone to creep more if fewer strands are used. "Elevated temperatures and higher draw weights increase this problem."

6. Question: Are there string materials that are better on some bows than others?
Answer: Bow manufacturers make their choice of string material based on many criteria but primarily safety and performance. Performance - meaning speed, low or no creep, vibration, and durability. Bow manufacturers do extensive testing. Some put a higher priority on certain criteria than others but they are all very conscious of safety.

7. Question: Can you use a different string than the type supplied with the bow directly from the factory?
Answer: Normally yes, unless there are some strict recommendations not to by the bow manufacturer. Check to be sure it does not void the warranty if a different string is used. Be sure to get the right number of strands of the new material you plan to use.

8. Question: Is it necessary to use "special" wax with certain types of bowstring material?
Answer: Not really. There are four main reasons for using wax on a bowstring.
1. To lubricate the fibers and prevent "fiber to fiber" abrasion
2. To help keep the "bundle" of strands together
3. To maintain and extend the life of the string
4. To help prevent water absorption

BCY applies a generous amount of synthetic wax in liquid form, which insures that from its origin the bowstring material is well lubricated inside and out. It is this process which gives the material its basic protection from fiber to fiber abrasion and helps keep the bundle of strands together. Generally the type of wax used would be a good quality standard "tacky" wax. At this stage it would be unusual for the wax to include silicone which is very slick and, particularly in the case of Flemish strings, makes it difficult to convert the bowstring material into a finished bowstring. However, after the string is made, it is recommended that the archer look for a "maintenance" wax that contains some silicone because a wax blended with silicone penetrates the string material very well and keeps the inside fibers lubricated as well as the outside. Wax can be applied with fingers, with a cloth, or with a chamois leather. It should be applied frequently and rubbed well into the string.

9. Question: Is it okay to wax the serving material on a bowstring?
Answer: There is no need for it on recurves or compounds. Some of the bowstring wax will probably show anyway. The center serving on most crossbows needs to be kept lubricated and wax can be used.

10. Question: How many twists can be put into a bowstring?
Answer: Twisting a bowstring keeps the bundle of strands together, shortens the string after creep has occurred, and helps reduce peep rotation. The amount of twists is not a specific number but 1/2 to 3/4 twists per inch is a suggested range.

11. Question: Does twisting reduce creep?
Answer: Not really. Eventually materials from 100% spectra or Dyneema (HMPE) will creep a little, especially under high tension in very hot temperatures.

12. Question: Is there any difference in the durability of a string made from colored material instead of black or white?
Answer: No.

13. Is there any difference in the string diameter of colored bowstring compared to natural or black?
Answer: Each type of bowstring material is made from the same size base material. Coloring is achieved by adding a color pigment. There will be a very minor diameter difference except for fluorescent colors which need heavy pigment to achieve the fluorescent color. Can be up to 12% larger diameter.

14. Question: Are there any benefits in a braided bowstring as opposed to the standard twisted product?
Answer: We produced braided bowstring material many years ago and have looked at it many times. Generally braided material is expensive. It does not improve the creep characteristics of the bowstring and normally reduces arrow speed.

15. Question: What is the life of a bowstring?
Answer: This depends on many factors but primarily the number of shots and the condition of the equipment. If an archer is shooting a high poundage bow every day and using a caliper release, the string should be checked very frequently. (Using a string loop will increase string life.) On a lower poundage bow, shooting fingers, the wear would be significantly less, therefore the life of the string much longer. But again, it is the archer's responsibility to check the string and keep it waxed. There are no rules. We know that with the high quality synthetic materials being used today, thousands of shots can be achieved. Archers should also check for tell tale signs of problems such as abrasion (fuzziness), high strands (which indicate a strand breakage underneath the serving), or excessive peep rotation - which can be an indication that one strand may have broken.

There are many reasons for string breakage. One of the most common is burrs in the cams / wheels on compound bows. It is the archer's responsibility to check the string carefully prior to shooting every time. As stated, thousands of shots can be achieved if the string is checked and maintained properly.

16. Question: How do I make a zebra string?
Answer: You can't. It's a patented product made by Mathews from a specially constructed material. You can make standard two color strings.

17. Question: What is the best center serving to use?
Answer: 62XS and Powergrip both grip well and have high durability. Halo is very tough and liked by many finger shooters.

18. Question: What is the best end serving to use?
Answer: For the ends on modern compound bows, twisted Spectra (HMPE) material is usually the best. Look at our 3D; it fits comfortably into most cam / wheels without riding up on the side walls, causing abrasion. If smaller diameter end serving is needed, we offer 2X twisted Spectra (a little smaller than 3D); or 008" twisted Spectra which is approx. 1/2 the size of 3D. Halo .014" is also a good option; it is small and tough.

62XS, 62 and Powergrip can also be used for end serving, usually in size .014.

On traditional bows, 400 nylon is a good bet.

19. Question: How tight should serving material be applied?
Answer: Tight enough to hold the serving in place and stop it separating. That's not very specific but what it means is that if you serve too tightly, there may be problems. In the center, you are crushing the bowstring material which can cause problems at a point where flexing occurs, and at the ends, if the serving is too tight, it "cracks" open when bent around the cam, especially if the bow is fitted with a radical cam.

20. Question: What is the difference between Spectra and Dyneema®?
Answer: Not very much. They are both HMPE products (High modulus Polyethylene). There are slight differences of fiber count. Spectra was used in the original Fastflight bowstring, still popular as BCY's 652. BCY uses mostly Dyneema which generally has a little less creep in comparable sizes.

21. Question: Does 452X® or X-99® fray?
Answer: All bowstring material will fray or fuzz if it's not properly maintained, meaning regularly waxed, so really the question is - Does 452 fray more than other bowstring materials?

Early production of 452 bowstring material included fibers lubricated with silicone. It was found that the silicone would not blend with our standard bowstring wax applied during manufacturing. This caused 452 material to dry out quickly and a dry string will fuzz of fray.

The fibers are no longer lubricated with silicone. We now use a special lubricant which blends well with our current production wax. This means that the 452 stays well lubricated. All current productions of 452 will show no more fuzzing or fraying than any other bowstring material. 452 is now called 452X®.

Note also that the percentage of Vectran in 452X® is approximately 33%. The lower the Vectran content, the higher the durability, the faster the arrow speed, and the lower the fraying. X-99® has the lowest percent of Vectran; 20%.

22. Question: Do bowstrings provide the same performance on different bows?
Answer: No, but it is generally accepted that small diameter string materials of 100% Spectra or Dyneema®, such as 8125®, will shoot faster, but of course stability and creep have to be considered.

The width of the wheel tracks and design of the compound bows can make a difference. Some bows have very wide and friendly wheel tracks, and speed tests have shown that blended materials such as X-99® and 452X® are not much slower than 8125® on these bows.

On some compound bows, particularly those with narrow wheel tracks, the use of string material with a high percentage of Vectran has resulted in problems such as sudden catastrophic failures.

So, the answer is really that any opinions given by archers on string material relate directly to the bow they are using and it is wrong to assume that the results will be the same on other bows.

23. Question: Bowstring material was made from Dacron, then from Fastflight. Now we see Dyneema®, Spectra and HMPE. What are these materials and which one is best?
Answer: HMPE means "High Modulus Polyethylene". Spectra and Dyneema® are both HMPE material. BCY uses mostly Dyneema® for Bowstring material and Spectra for serving material. Products described as HMPE are made from either Spectra or Dyneema®. Spectra and Dyneema® are both very, very strong. Breakages are rare with either material. However, less creep (stretch) will be experienced with SK75 or SK90 Dyneema® because it is stronger. Breakages can occur because of abrasion, rough spots at the ends of the bow, etc., but not because of fiber strength if the correct number of strands is used.

Which is best? Bottom line... our opinion... its Dyneema® SK90 or SK75, which are the strongest HMPE yarns available in suitable sizes for bowstring material. BCY uses 100% Dyneema® or a blend of Dyneema® and Vectran in most of its Bowstring materials.

24. Question: What is the best bowstring material for a Recurve bow?
Answer: First it is essential to be sure that the bow is designed to shoot with the modern, high tenacity bowstring materials. Any doubt, use Polyester (Dacron) to avoid limb tip breakage. Which string material is best for recurves? It's not an easy question. We know top recurve shooters are using our 8125® and our DynaFLIGHT 97®. So there's really not a clear recommendation, but we see a preference for Dyneema® which offers high strength and durability. Less strands can be used on lower poundage recurves, which helps arrow speed, particularly if the draw length is short. X-99® also shows good performance on Recurves.

25. Question: What is the best bowstring material for a Crossbow ?
Answer: 100% Dyneema® is recommended and Dynaflight 97® is popular. More recently, Mercury 2 was introduced. It's the same size as '97, just a little stronger. Use BCY Braided Spectra Center serving and 3D end serving. If a smaller diameter end serving is needed, try Powergrip 009.

Thanks for your interest in BCY products.

Manufactured in the USA

BCY Bowstring
155 Industrial Park Road
Middletown CT 06457

Telephone: (860) 632 - 7115