Reader Question: I’ve been shooting the same arrows from my bow for several years. I’m down to my last couple that I use for hunting, and I picked up a half-dozen that are of a different spine size. Does spine size really matter when it comes to archery?

D&DH’s Dan Schmidt: Yes, arrow spine size is critically important because it dictates the arrow’s stiffness, which is essential for consistent and accurate flight, and it also plays a role in safety. An incorrectly spined arrow won’t flex correctly during release, leading to inconsistent flight, poor groups, and, in the case of a weak arrow, potentially exploding and causing injury.

Why Spine Matters

1. Consistent Flight: A properly spined arrow flexes in a controlled, consistent manner when shot, allowing it to pass the bow’s riser cleanly and then stabilize quickly in flight. 

2. Accuracy: The right spine ensures the arrow flies true, leading to tighter groups and better overall accuracy on the range or in the field.

3. Safety: A shaft that is too weak for the bow’s draw weight can over-flex, leading to a catastrophic failure and potentially causing the arrow to explode upon release, which is dangerous to the archer. 

Factors Affecting Spine

The spine of an arrow refers to its inherent stiffness, but the dynamic spine is how the arrow behaves when shot from a specific bow. Several factors influence the dynamic spine:

4. Draw Weight: The force of the bow.

5. Arrow Length: Longer arrows are more limber (weaker dynamic spine).

6. Point Weight: Heavier point weights increase the arrow’s flex.

How to Find the Right Spine

7. Measure Draw Weight: Determine your bow’s exact draw weight.

8. Determine Arrow Length: Your arrow’s length is also a key factor.

9. Use a Spine Chart: Consult an arrow manufacturer’s spine chart, which correlates draw weight, arrow length, and point weight to recommend the correct spine rating for your setup.

10. Fine-Tune: Adjust arrow length and point weight to achieve the correct dynamic spine for your bow.

Find your correct arrow size at eastonarchery.com/selector