Arrow Spine Question

[3rdTripper]

I was wondering if someone could tell me if total arrow weight(i.e. insert, nock, broadhead, arrow and vanes/feathers) has an effect on which spine I choose. Any help would be great.

 

[JayMc]

Spine is deflection over a span, basically how much an arrow bends compared to all other arrows under the exact same circumstances.

The spine weakens by adding weight to the front and back of the arrow, which is the sum of the parts you listed. The biggest weight you add is the point so the spine charts always ask for point weight and arrow length and assume that the nock, vanes, etc. are pretty much all going to weigh about the same.

If you are underspined you can decrease point weight and go with lighter vanes to stiffen the arrow.

If you are overspined you can add weight to the nock end of the arrow (like a wrap, heavier vanes or weight tubes) to weaken the spine a bit.

You can download a demo of a spine selector at http://www.pinwheelsoftware.com/ that lets you play with combos. I'm not sure how long the demo last though. The full software is really cool if you're an archery dork like me.

 

[Radar]

Point or broadhead weight , along with arrow length will have the biggest effect on spine . Increasing the broadhead weight , or increasing the length of the arrow weakens the spine . Shortening the arrow or reducing the point weight stiffens the spine .

 

[Toxophilite Phil]

Adding weight to the front of the arrow will make it weaker. Weight added to the back will stiffen it up. You want your front weight to be a little heavier than your back weight. Spine is relatively easy to get with the amount of arrows and material out there today. And with carbon arrows covering such a wide range or draw weight, spine isn't that big of an issue. What is a bigger issue is the Front of Center. This can make such an impact on your shooting it isn't even funny. Most bow makers say 7-10% will give you good flight and it does with field points. For a hunting set up most say more toward the 10% mark but I prefer around 12-13%. I can get great flight and penetration with it set like that.

 

[3rdTripper]

Thanks ya'll for all ya'lls help.