Archery term
Arrow Spine
Definition
Arrow spine is the measure of an arrow shaft's stiffness, or how much it resists bending. It is most commonly expressed as a static spine number equal to the deflection in thousandths of an inch when a standard weight is hung from the center of the shaft supported at two points; a higher number means a more flexible (weaker) shaft and a lower number means a stiffer shaft.
Why it matters
Spine must be matched to the bow's draw weight, the arrow's length, and the point weight so the arrow flexes correctly off the bow and recovers cleanly in flight. A poorly matched spine produces erratic arrow flight and inconsistent groups, which is why spine selection is the foundation of building a tuned arrow.
Related terms
Where it applies
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