MdDave

i really dont understand this... can someone please explain to me how i find my arrow spine...whatmy arrow spine needs to be... an what happens if im underspined or over spined..i have no idea .,Thanks

JOE PA

Spine is the stiffness of the arrow. It affects how the arrow absorbs energy from the bow, and travels forward to the target. It is measured by placing an arrow between two supports (24" apart, I think), and hanging a 2# weight from the arrow's middle. Then the amount of bend is measured. Underspined arrows would bend too much, and would be difficult to control. They would continue to oscillate for a good distance downrange. Underspined arrows are very difficult to tune with broadheads. Overspined arrows are too stiff, and don't bend enough. In my personal experience, this does not seem to be much of a problem for a compound bow shot with a release aid. I did build a spine tester 2 years ago, and found that some all carbon arrows vary quite a bit when you compare the stiffness at different places around the shaft, and also vary a lot when comparing different shafts out of a dozen.

Black Frog

I believe the standard is 880grams hanging from a 28" span.

JOE PA

Thanks for the correction. It has been a while since I measured any arrows. I know I came to the conclusion that, after measuring ACCs against the all carbons I tried, I should have just saved the $ on the spine meter, and bought more ACCs. My spine meter was based on plans I saw on line. It is nothing like the amazing work of art that Black Frog made. Really a fine piece of equipment.

Black Frog

I think a lot of people would be well-served to heed that bit of advice!

MdDave

ok so how do i find the right spine for my setup????

brucelanthier

Basic factors to determine the arrow you want would be draw length, draw weight.

Depending on the type of arrow you want then there could bea number ofother factors.

What is your setup?

WesternMdHardwoods

Bruce...Daves setup goes roughly like this!
High Country Carbon SSR bow
DRAW--29''
Weight--62-64 lbs.
He is currently shooting easton st.epic 500's!

I think he is looking for a way to tell if this is the correct arrow for his setup? Me and him shoot together and we both are curious on this subject? When we went to the bowshop and asked the tech. what arrows would be best spined for our bows, we both walked out of there with st.epics i got 400's and he had 500's?? Me and him are both not very sure about the tech and think he could of just handed us any arrow and said "Yup these will work 4 Ya"?? Hope this helps You!

brucelanthier

Using the Easton shaft selector, for Dave to be shooting 500's @64 lbs with a 100grain tip his arrow length would have to be 24". Those arrows are a bit weak spined for his setup. For a 64lb draw, 100grain tip and 29" arrow the Easton shaft selector says he should be shooting an ST Epic 340.

brucelanthier

This is a link to the Easton shaft selector software. It is 3.3MB and you can install it on your PC. It ask you a couple of questions and then gives you the appropriate easton arrows.

2006 Shaft Selector Software for Windows