To determine the spine arrow you need, you should consider the following factors:

• Draw weight: As draw weight increases, so should arrow rigidity (spine). The first variable you need to look at is draw weight.

• Arrow length: Given a specific arrow spine, an arrow that is shorter will be more rigid than a shaft of the same spine that is longer. For example, if you have a 60 lb. bow with a 24" arrow, you would need a more flexible shaft than a.

• Arrow point weight: Adding weight to the front of the arrow weakens its spine. Archers selecting arrows should stick to the manufacturer’s spine recommendations. Moving away from those recommendations can hurt accuracy.

Different manufacturers have their own spine charts, so its important to reference the applicable spine chart of the arrow manufacturer you have interest in. You can also use a custom arrow builder that will denote what spine shaft you should be considering.

Here are some general guidelines to help you get started:

• As a rule of thumb, you should use an arrow with at least 5 grains of weight per pound or draw weight (if you are shooting a 60 lb. bow, you should use an arrow of not less than 300 grains) .

• For a 70 lb. bow and 29.5" draw length, arrow spine could range from 260 to 350 depending on your setup.

• Manufacturers recommend which spine should work best for various draw weights, arrow lengths, and point weights. For example, Gold Tips spine chart recommends an arrow with a 500-spine rating for a 50-pound compound bow that shoots 27-inch arrows with a 100-grain point. If you increase the bow’s draw weight to 60 pounds and shoot that 27-inch arrow, the chart again calls for a 400 spine. But if you increase the arrow length to 30 inches for the 60-pound bow, the chart calls for a 340 spine.

Its important to note that these are general guidelines, and you should always consult the spine chart of the arrow manufacturer you are interested in or seek advice from a local Black Eagle Dealer.