What Is The Arrow Spine?

By Moritz

Nov 02

In my post about the Archers Paradox I mentioned the “arrow spine”.
Now it’s time to answer the question:

What Is The Arrow Spine?

When you read the article mentioned above, you know that arrows are not as stiff as metal but bend when they are shot.
The arrow travels then toward the target flexing left and right until it hits the target.

Without that, we wouldnt’ be able to shoot the way we do, because the arrow would either fly to the right or the left, depending on which side of the bow it is held.

But not all arrows are the same!
Just take some different arrows in your hand and try to bend them.
Some bend more, some bend less than others. Their stiffness is different.
To messure this stiffness, archers started using the term “arrow spine” which lets us know how much the arrow will flex when leaving the bow.

The lower the spine value, the higher the stiffness of the arrow.
Read on to learn why:

How To Find Out The Arrow Spine?

There are “spine meters” like in the image below that measure the deflection of an arrow with a certain weight (1.94 lb) hung at the middle of the arrow.
If that deflection is high, it means that the arrow is not very stiff. Therefore the spine value will be higher.
But if the arrow won’t bend much under the weight, it means that it is stiffer and the value will be lower.

All that this spine meter tells us is how many inches the arrow bends under the weight of 1.94 lb.

A spine meter

A spine meter. Used under creative commons from: Jomegat

Some examples of spine values:

If an arrow bends 0.3 inches, we multiply this number with 1000 and get the spine value of 300.
But if it bends 1 inch, the spine value would be 1000.
(We always multiply with 1000 to get numbers that are easier to deal with.)

I think you understand now why a lower spine value means that the arrow is stiffer than an arrow with a higher spine value.

How To Choose The Correct Arrow Spine?

That one can be a bit tricky, but the rule of thumb is:

The weaker your bow, the lower the stiffness of your arrow should be.

When you are shooting a right handed bow and your arrow is always flying to the left, you know that your arrow is too stiff.
If it flies to the right, your arrow is not stiff enough.
This is one way to find out the correct arrow spine:
Shooting arrows a few times and see if you can shoot them accurately, or whether they fly off to one side or the other.

What Is Arrow Spine

Correct Spine. Used under creative commons from: OgreBot

Another way, and maybe the easiest one, is to use a chart like you can find here.

Don’t forget that arrow length is important, too!
The longer an arrow the easier it is to bend it.
So when you are shooting with long arrows, because of your long draw length, you will need stiffer arrows than archers with shorter draw lengths.

How Much To Worry About Arrow Spine?

As an absolute beginner I wouldn’t worry too much about it.
You will have enough to do with learning how to handle your bow.
Of course the spine shouldn’t be completely too high or to low for your bow, but you don’t need to find the spine that is 100% perfect.
If it is “just right” it is ok, too.

Once you have more experience or want to shoot in professional competitions or go hunting, you have to take it more seriously.
Make sure the arrow spine fits your bow.
There are archers who religiously check each and every arrow before they shoot it.
If one is too stiff or not stiff enough, they will simply not shoot it.

Any More Questions About The Arrow Spine?

If this isn’t your first time on my site, you know that I like to keep it informative but simple.
I could go into much more detail about the arrow spine, but I think I gave enough information to understand what really matters.
I don’t want to bore you with all the scientific details.

I believe that we are here to have fun with archery.
Use the chart above or ask in the shop where you are buying your arrows to pick the right ones for you.

Did I answer the question “What Is The Arrow Spine?” or would you like to know more about it?

Let me know in the comments below and if you want to know more, I will add some to my article.

Happy shooting everybody!

Moritz

About the Author

Hi, as a huge archery enthusiast I love sharing my knowledge about archery. Enjoy your stay and don't hesitate to leave a comment if you have a question.

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