How is a spin value calculated

Spine value calculator - find the right spine

Calculate the spine value

Our spine value calculator will help you to find the right spine for your arrows.

Find the right arrows here

Did you get the result of your spine value? Then you have the option of using our arrow finder to find the right arrows for you and your bow.

The advantages at a glance

  • Reliably find the right spine value
  • Helpful orientation for beginners
  • Purchase decision for carbon and wooden arrows
  • Better arrow flight without specialist knowledge

What is the spine value?

The spine value can be referred to as the degree of hardness or the deflection value of the arrow. Arrows with a high spin value are very soft. An arrow with a low spin value tends to be hard.

A bow with a light draw weight, for example, needs an arrow with a high spin value, i.e. a soft arrow. A strong bow requires a hard arrow with a low spin value.

So that the correct spine value of the arrows can be determined, you need to specify your personal extension (i.e. the arrow length) and the draw weight of your bow.

Why is the spine value important?

If you take a closer look at the nocked arrow on the bow, you will notice that the arrow does not point straight forward, but sideways past the bow.

So that the arrow can still hit the targeted target, it has to bend around the bow, so to speak. The stage in which the arrow emerges from the bow window is very important. The moment you release the arrow, the fingers inevitably give the tendon a lateral movement.

At the same time the arrow is compressed by the acceleration of the tendon. If the bend is correct and the arrow is correctly matched to the draw weight and the extension, the arrow flies around the bow window, so to speak, and leaves the bow correctly.

Where does the spine value come from?

The Easton company set itself the task of defining a standard for determining the spine value.

First of all, it should be said that the Easton company is one of the largest producers of arrow shafts. This information only so that you can relate to this name.

The standard for determining the spine value is as follows. A 29 inch long shaft is used as a reference. A shaft is the pure body of the arrow, no point, no feather and no nock.

This shaft is placed in the center of an apparatus that has two arms 28 inches apart. A weight of exactly 1.94 pounds (1 kg) is now placed on the shaft in the center.

Logically, the shaft flexes to a certain extent. The further the shaft bends, the greater the spine value, logically.

The higher the spine value, the softer the arrow. If you have a bow with a low draw weight, you need a soft arrow with a high spin value. If you have a bow with a high draw weight you need an arrow with a low spin value.

Via the spine value calculator

With our calculator you can easily and quickly calculate the required spine for your arrows. Simply fill out the form above to receive the right spine for you.

Based on the spine value, which you can easily calculate with our calculator, you can buy and find the right arrows for you. So that you can use the spine value calculator correctly, you need to know your extension or the correct arrow length that you need. With our statement calculator you can have your theoretical statement calculated.

How does the calculator work?

The spine value calculator is based on the information from The calculation method selected there is based on percentages that vary depending on the information made in the spine value calculator. The appropriate spine that is output is always adjusted as a percentage. Most spine value calculators on the Internet only calculate with fixed lbs values ‚Äč‚Äčthat change and adapt the spine value. The percentage variant is more precise in this case and more logical in itself.

An example

The calculation in the spine value calculator assumes an arrow length of 28 inches by default.

You choose a draw weight of 40 lbs and an arrow length of 28 inches

If you leave out the other information for a simple explanation, the ATA value (spin specification for wooden arrows) would not deviate, since an arrow length of 28 inches is the standard value. So the correct ATA spine value would be 40 lbs.

You choose a draw weight of 40 lbs and an arrow length of 30 inches

Since the 30 inch long arrow differs by 2 inches from the arrow length drawn as the base of 28 inches, the value affects the required spine value.

Our spine value calculator increases the required spine value by 18% (varies with other arrow lengths) and changes the value as a percentage. In connection with the other options, which also influence the spine value as a percentage, this gives a correct result. Our result would be a matching spine of 47.2 lbs.

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