Wood Arrow Spine

To get arrows with the correct spine for your bow, you first need to know your exact draw length and the weight that you are pulling from your bow. The standard measurement for a bow is based on 28″, but many of us fail to draw to that length; most of the time we draw less. A rule of thumb is to add five pounds of spine for each inch over 28″ as well as an additional five pounds for the broadhead. For each inch under 28″, you will subtract five pounds. For example, if you are drawing 65 pounds at 29″ you would add five pounds for the inch over 28″ and another five pounds for the broadhead, ending up needing an arrow spined at 75#. I would also err on the high side, adding another five pounds. In this case, I would opt for shafting that is spined 75# to 80#.

A recurve bow will generally accept a wider range of spine in its arrows because of the near centershot design of the bow. A longbow, on the other hand, will require a tighter tolerance due to the arrow having to bend farther around the bow’s riser when shot. But this is not true for all archers. Bow weight, bow design, release, and numerous other individual shooting characteristics will all play a part in what spine arrow will work best for you.

The chart below shows the recommended arrow spine for any given bow weight and draw length. But these are not set in stone; rather, you should use these figures as starting points.

 

This tip is an excerpt from T.J.’s book The Traditional Bowhunter’s Handbook.

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2016-12-14T13:46:51+00:00

About the Author:

T. J. Conrads is the Editor, Publisher and Founder of Traditional Bowhunter Magazine. He has written many articles over the years, and has also written two excellent books: The Traditional Bowhunter's Handbook and Campfire Reflections.

2 Comments

  1. Chuck Yoder January 3, 2017 at 3:06 pm - Reply

    I have a question, My arrows are 28″ but I only draw 26″ My bow is 40lb @ 28. If my draw weight is 35-40lb on the scale above, do I look at the draw length (26) above or at the draw length which is (28) same as my arrow length ? Would it make any difference in spine if I cut my arrows to 26″ ? I really would prefer to keep my arrows at 28″ What do you think ?

  2. T.J. Conrads January 4, 2017 at 11:05 am - Reply

    Hi Chuck. As a rule, shortening a shaft can lead to anywhere from 2#-5# spine increase; the shorter the shaft, the stiffer it becomes. Since I don’t know what your arrows are spined for, the best approach is to shoot them at 28″ first and check for quality flight. Look for porpoising and fishtailing off the shelf, and see how fast the arrow recovers from paradox. (I use a video camera mounted on a tripod behind me, or have someone watch several arrows to see how the arrow reacts.) Place with brace height (for fishtailing) and nock set (for porpoising) and see if the flight improves. If you need to make adjustments, cut 1/4″ to 1/2″ off the shaft, reapply the head of your choice, and go back and test for flight. Do this until you have achieved the flight you are pleased with.

    Type of bow makes a huge difference in flight of the same shaft due to center shot, or lack of it. A recurve usually is closer to center shot than a longbow, and a selfbow may have none. The same shaft may shoot differently from each bow. But playing with the tuning of your arrow to a particular bow allows you understand both bow and arrow, and how they react with each other. In the end, once you have attained the flight characteristic of the arrow to the bow, your confidence in shooting will also increase, as well as the pleasure.

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