Spine Selection

Find the right spine for your setup.

When we talk about an arrow’s spine, we’re talking about how much it flexes. We’re talking about its stiffness. Every arrow should flex when it leaves the bow, however, the flex should be limited within the safe operation of the product. If it flexes too much (weak spine) then its flight will be erratic. If it doesn’t flex enough (stiff spine) then the arrow will have no forgiveness. Consistent accuracy usually suffers in either case.

Every arrow manufacturer has a spine-selection chart, so you know which shaft to choose for your draw weight and arrow length. (Some even factor in the bow’s speed rating, since faster bows exert more force on an arrow.) And every shaft bears its manufacturer’s spine rating.  Unfortunately, the numbering system for spine ratings is not uniform from manufacturer to manufacturer. So don’t assume the numbers you see on shafts across manufacturers are comparable. Check the below chart to see what fits your style.

* Tip Weight = Includes insert weight, and broadhead/field point
** Arrow Length = Length of arrow from broadhead mounting surface to nock mounting surface. When using extended post inserts, the length of the metal insert can be subtracted from the arrow length as this is a non-flexing portion of the shaft. Consult a Sirius Archery Staff member if you have any questions!
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