Spine indicates the deflection (flexural rigidity) of an arrow shaft in pounds. This value must match the characteristics of the bow to achieve good shooting performance.
Spine is an English term. The (static) spine of an arrow refers to how much it bends under unaccelerated load. For wooden arrows, it is measured by placing a 2-pound weight under the arrow at intervals of 26 inches and then placing a 2-pound weight in the center. A 40# bow requires approximately one arrow with a 40# spine. Finding the perfect arrow for your bow is a matter of trial and error, as the archer's shooting technique, the bow's shooting characteristics, the grip, and other parameters also influence the results.
Arrows made of other materials (such as carbon or aluminum) have different spine values; this is expressed as deflection in thousandths of an inch. This results in shafts of 300 or 1000 mm, for example.
Weaker bows require softer (in terms of spine) arrows than stronger bows. However, for the right arrow, not only the static spine is important, but also the dynamic spine , which is influenced by, among other things,
- The weight of the tip : A heavy tip requires more energy to accelerate (imagine the difference between using a wooden stake to get a golf ball rolling and a Volkswagen Golf rolling), and the arrow bends more. For this reason, the raw shaft test is always performed with the tips already mounted.
- the length of the shaft : the longer the arrow shaft, the easier it is to bend.
This means there are several options for correcting the spine during the raw shaft test. A shaft that's too stiff can be thinned or given a heavier tip; a shaft that's too soft can either be shortened or given a lighter tip (or used for a lighter bow).
.png?h=64&w=200&mode=max&scale=canvas&format=webp&quality=90&autorotate=true){kind=logo}
.png){kind=logo}