Choosing the right arrow is a lot like choosing the right golf club. There are different elements to consider, depending on how much force you want to hit the target with or the distance at which you hope to cover with your shot.
One of the most important elements of picking the right arrow for the shot is the arrow’s spine, or what we might think of as the stiffness of the arrow. If we want a straight shot, then a stiff arrow would make sense, wouldn’t it? Or is there a point at which an arrow is too stiff?
An arrow encounters problems when it is too stiff, and also when it is too weak. The stiffness of the arrow interacts with its other aspects to determine how it flies. The length and weight of the arrow, along with the weight of the arrow’s head all interact with the stiffness of the arrow. To achieve the best shot, the stiffness of the arrow needs to be increased or lowered; otherwise, the arrow will veer off target.
To learn more about how the arrow’s spine affects its flight and how to tell if you need a thicker or thinner arrow, keep reading. We’ll cover these and more, so you can make sure you pick the right arrow for the job.
How the Stiffness of the Arrow Affects Your Shot
The stiffness of an arrow is important because of how it flexes. Arrows with a lower spine rating are thinner, thus they simply have a less stiff spine. They wobble more where a thicker arrow would wobble less.
As the arrow leaves the bow, it has to flex and wobble. That’s just the way the force is exerted on it and part of the physics of the arrow. Speaking of physics, we talked about the physics of arrows in depth in this article. To sum it up quickly, as the arrow travels through the air, it will begin to straighten out based on how the different elements of length and weight interact with the air and the arrow’s spine.
An arrow with a weak spine flexes a lot, whereas an arrow with a stiff spine may barely flex at all. To those who don’t know much about archery, a weak spine may seem like something you wouldn’t want. After all, things that are weak are typically bad. However, there is more to it than this. Archers understand that not all shots are the same.
When most people picture shooting a bow, they picture shooting at a target that is directly in front of them. But, oftentimes, we need to shoot in an arc around us. Take hunting for example; say you’re up in a treestand and a deer comes by. It’s more likely to come from either your right or your left than it is to come at you from straight ahead. Every direction has a 33% chance of being where the deer comes from, meaning there’s a 66% chance it’s from a side.
Whether you shoot from the left or right will have an effect on your shot. You will want to select an arrow with a different spine for each shot. This is because an arrow’s spine will affect the direction it veers off target directly.
One way to test if your arrows have the correct spine rating is to set up a camera and film yourself shooting them. You will want to watch how the arrow flies compared to your target. Arrows with a weak spine will travel more toward the right. Likewise, arrows with a stiffer spine will travel more toward the left. If you are aiming straight ahead, then you will want an arrow that has the perfect spine rating.
However, since you may need to shoot targets from either direction, it can be a smart idea to pack three different arrows. Pack a couple arrows with a spine that is too stiff and a couple with a spine that is too weak. You’ll still want the majority of your arrows to be just right, but using this specific strategy can give you an advantage in your accuracy, depending on the situation.
How Do I Buy the Right-Sized Spine?
Arrow manufacturers pretty much stick to the same standards, so anyone who needs an arrow of a certain stiffness can purchase their goods. If every company had its own way of calculating the spine rating of their arrows, then it would limit the amount of business they receive.
However, since there can be minor differences between companies, most companies still also provide plenty of charts, graphics, and tools for ensuring that you select arrows with the proper spine rating. These can be found on most big distributors’ websites. You can use these charts to select the arrows you need.
However, I want to recommend that you experiment with your arrows yourself and try different ratings to get a sense of how they work. Once you find the ones that work best for you, simply mark down the rating, and you will know what to buy from then on.
How Do I Test the Spine Rating?
If you don’t know the rating of the arrows, you will then want to get yourself a spine tester like the one from HOMELEX. It will help you to test the spine and get back a rating from it. This is a pretty inexpensive way of doing it, though it doesn’t have as much accuracy as some would desire.
Another inexpensive way of testing the spine of your arrows is to make your own tester. There are many videos that will teach you how to make your own spine testers like the following one:
These may be fun to make, but they can be more trouble than many people want to deal with. Mistakes in their creation can also make them terribly inaccurate.
For a more accurate reading, you should take your arrows into an archery shop or local or nearby archery range. Experts will be able to give you a more accurate rating, so you won’t have any doubt about your arrows while shooting.
How Is Spine Rating Calculated?
Picking the right spine rating has also been called The Archer’s Paradox. Thankfully, spine ratings have made it easier for archers to pick which spine is the best for their needs. In order for spine ratings to work effectively, they need to have a typical method for measurement.
The two methods that are used the most often are the tests done by the American Society for Testing and Materials and the Archery Trade Association. If you are shooting arrows made from a form of metal, then the test that you will be interested in is the American Society for Testing and Materials test. Wooden arrows are measured according to the Archery Trade Association.
During each test, the arrow is placed into two supports that are kept a certain distance apart. The middle of the arrow then has a weight pressed into it. How much the weight affects the arrow determines the spine rating it is given. The distance apart and the weight is determined by the material it is made from.
Can You Change the Spine of Your Arrows?
No, not really. There are two different forms of spine. The static spine is the arrow shaft itself. The wood or metal, however thick it is, cannot be altered; it will be that thick.
However, what we call the dynamic spine can be changed. This is what the spine is while it is in the air. When we talk about the weight and length of the arrow having an affect on the spine, we are talking about the dynamic spine.
The dynamic spine can be changed by increasing or decreasing the weight of the arrow tip. Increasing or decreasing the length of the shaft changes how it flies. Even the weight of the nock and the bow’s draw will change the dynamic spine. When we alter an arrow to change the spine, it is this spine we are changing.
So, in a way, we both can and can’t change the spine. It just depends on how we are considering the question.
Outro
Now you can see that, not only can an arrow be too weak, but it can also be too stiff. However, even though it is a bad thing for some shots, it can actually be a benefit in others. It all depends on what you are trying to do with your bow.
Remember that the best way to understand how this works in action is to practice yourself. Try this in action by purchasing arrows such as these. These same arrows can be purchased in two different spine ratings, so you can see the difference in action with arrows that have been manufactured the same way.
When it comes to archery, the best way to learn is by doing. So get out there to your target range and start letting your arrows fly.