Arrow Spine Calculator

How to Use the Arrow Spine Calculator

The Arrow Spine Calculator is a helpful tool designed to assist archers in determining the optimal arrow spine for their setup. This guide will walk you through each step required to use the calculator effectively.

Step 1: Enter Arrow Length

Start by entering the length of your arrow in inches. This is required to ensure accurate calculations. Please ensure that the length you enter is between 20 and 32 inches, with permissible increments of 0.25 inches.

Step 2: Enter Draw Weight of the Bow

The next step involves entering the draw weight of your bow in pounds. Input a value ranging from 20 to 80 pounds. This field is necessary for the calculation and only accepts whole numbers.

Step 3: Select Point Weight

Select the weight of the arrow point from the available options. Choose between 75 grains, 100 grains, 125 grains, and 150 grains. Make sure to choose the point weight that corresponds to the equipment you are using.

Step 4: Choose the Bow Type

Next, you must specify the type of bow you are using. You have the choice between a Compound Bow and a Recurve/Longbow. Each bow type has a multiplier (1.0 for Compound Bow and 1.2 for Recurve/Longbow) that will be used in the calculation.

Step 5: Calculate Recommended Spine

With all necessary fields filled, the calculator will determine the Recommended Spine for your arrows. This value is calculated using the formula:

(p bowWeight * bowType * (arrowLength – 1)) / (pointWeight / 100)

The resulting value is adjusted to a whole number for ease of interpretation.

Step 6: Understand the Spine Range

The calculator also provides a Spine Range, which denotes how much deviation your arrow spine can have while still performing optimally. This range is calculated as 5% of the recommended spine value, and it will be displayed with a prefix ±.

Step 7: Review the Recommended Spine Range

The final result is the Recommended Spine Range, which shows the recommended spine value along with the allowed variation. It’s displayed as the original spine value followed by ±5%, representing the inclusive range suitable for your setup.

By following these steps, you ensure that you have accurately and effectively used the Arrow Spine Calculator to optimize the performance of your archery equipment.