Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
Arrow spine is the stiffness of the arrow, measured by how much it deflects (bends) under a standard test. A lower spine number means a stiffer arrow (e.g. 300 spine is stiffer than 600 spine). The paradox of archery — that an arrow bends around the bow before straightening — requires matching the spine to the draw weight and arrow length. An underspined arrow (too flexible) flies left for a right-handed archer; an overspined arrow (too stiff) flies right. Point weight, bow type and arrow length all affect the required spine.
- Lower number = stiffer spine
- Must match draw weight and arrow length
- Underspined flies left, overspined flies right
- Point weight, bow type also affect selection
In practice
Getting spine wrong causes real accuracy problems: too stiff a shaft for your draw weight flies erratically left or right of target (for a right-handed shooter) as it fails to flex correctly around the arrow rest during the shot, while too weak a shaft over-flexes and porpoises in flight — manufacturers publish spine charts matching draw weight and arrow length to the correct spine value.
FAQ
What happens if my arrow spine is wrong?
Too stiff or too weak a spine for your setup causes inconsistent arrow flight and poor accuracy, even with perfect form — the arrow literally flies off-axis as it leaves the bow.
Does arrow length affect the spine I need?
Yes — cutting an arrow shorter effectively stiffens its spine, so spine charts always specify spine value against both draw weight and the exact arrow length.