Arrow Spine Calculator — Shaft Stiffness Guide | ArcheryMetric

Determine the correct arrow spine for your bow setup. Calculate required stiffness based on draw weight, arrow length, and point weight for perfect tuning.

FAQ

What is 'static spine' vs 'dynamic spine'?

Static spine is the physical stiffness of the shaft. Dynamic spine is how the arrow actually bends when fired. Draw weight and point weight significantly affect dynamic spine.

What happens if my arrow spine is too weak?

A weak spine causes the arrow to flex excessively (fishtailing), leading to poor accuracy and potentially dangerous shaft failure upon release.

How does point weight affect spine?

A heavier point makes the arrow act weaker (increases dynamic spine). If you switch from a 100-grain to a 150-grain point, you may need a stiffer shaft.