A term that often confuses archer is stacking or archery stacking as some may call it. When you are reading reviews, some archers mention that their bow has stacking at a certain draw length. It is indeed important to buy a bow that doesn’t stack at your draw length. Therefore, in this article I will explain what stacking is and why it’s is bad.
Stacking the exponential draw weight increase when a bow is drawn further than it’s designed to. Every bow stacks, but each bow stacks at different draw lengths. Shorter bows for example stack earlier than longer bows. You want to avoid stacking because it makes your bow harder to shoot due to the sudden increase of draw weight.
The paragraph above is a summary, but there is much more to it. Therefore, I will first explain in detail what stacking is and what it looks like. Next, I will explain why stacking is bad for your accuracy. At the end of this article, I will give you some tips to detect and avoid stacking.
What stacking is
As I mentioned earlier, stacking is the exponential increase near the end of the draw. This, however, only makes sense when you understand what a normal draw graph looks like.
The relationship between draw weight and draw length
Normally when you draw a bow back, there will be a linear relationship between draw weight and draw length. This means that for every inch you pull back, the draw weight will increase with a certain number of pounds.
This linear increase in draw weight feels natural and makes for a comfortable shot. It also has the most effective energy transfer to holding weight ratio. Meaning that you can shoot your arrows faster without holding a heavy bow. I will discuss this in more detail later.
What stacking looks like
So, when a bow stacks, the draw weight will increase exponentially near the end of the draw weight.
This is easy to see when you measure draw weight, but you can also see this when pulling back a bow. You just need to know what to look for. Stacking occurs when the limbs of the bow are moving more downwards than backward. This happens when the angle of the string to the bow limb is beyond 90 degrees.
Why bows stack
So why is this 90-degree angle such an issue for bows? Well, to answer that question, we must discuss how a bow works in more detail.
When you draw back the string, the limbs will start to bend backward. This allows you to store the energy of your draw in the limbs. Essentially a limb is just a giant leaf spring.
Just like a leaf spring, a bow limb is bendable in two directions forward and backward. You can’t bend it any other way without serious force and potentially damaging the bow.
When the angle between the string and limbs exceeds 90 degrees. The limbs will start to be pushed inwards. Since a bow is not designed to bend in this direction, it will start to stack.
When does a bow stack?
Bows start to stack when they are past their designed draw length. This can differ wildly per bow. Some bows may stack before 28 inches, while most bows stack after 32 inches. Generally, longer bows stack later in the draw because you must draw further to reach the 90 degrees we talked about earlier.
If you are still confused about this, watching the video below might help.
How recurve bows reduce stacking
As we discussed before, shorter bows will stack earlier in the draw. But using long limbs is not always practical, luckily recurving the limbs can also severely reduce stacking.
When a recurve bow is not drawn the tips of the limbs will either be vertical or pointing forward. Therefore, there will be no string angle at all from the start of the draw.
If we compare this to a longbow, you can see that the tip of the limbs points backward. As you can see in the picture, there is already some string angle. By drawing the bow, this string angle will only increase.
Therefore, recurve bows will start stacking later because there is no initial string angle. And because the recurves require a longer draw to be drawn to the 90-degree string angle.
Important note: string angle is always measured from the limb tip. Therefore, the recurve bow has no string angle because it's flat to the limb on the tips.
Why stacking is bad
Okay, we now answered the first question but now we must discuss why stacking is bad. Still, quite a lot of archers believe that stacking is not an issue or even beneficial. Therefore, I want to discuss the main reasons why stacking is a bad thing.
It makes it harder to draw the bow
As mentioned earlier, the linear draw weight of a recurve bow makes for a smooth pull. Therefore, a bow with a linear draw weight is easier to draw. Also holding a bow at full draw becomes much more difficult. Which makes it more difficult to keep your bow arm steady.
Since the draw weight increases significantly at the last few inches of the draw, changing the draw length can have a major influence on the flight path of the arrow. If you draw a bit further, your arrows will fly a bit faster and which leads to higher shots.
This is already an issue in archery but stacking only makes this issue worse.
Less efficient power transfer
Some archers believe that stacking is beneficial because it increases the draw weight of the bow while keeping the bow small. But the actual benefit of the increase in draw weight is negligible. The thing is that most people think that arrow speed is influenced by the peak draw weight. But that is not the case.
Compare these two figures below. You can see that both bows have a maximum draw weight of 40 LBS. But the bow with stacking only has this near the end of the draw. Since the arrow is accelerated along the full length of the draw (minus the brace height), the bow without stacking will be much more efficient.
This is one of the major advantages of compound bows. The draw weight increases to the peak draw weight very fast, then it decreases near the end to create the let-off effect. Therefore, you can hold the bow at a comfortable draw weight, while still having a lot of energy stored in the limbs. Read the article below if you want to know how compound bows work:
Decreases the lifespan of the bow
Most bows will not get damaged if you draw it to the point where it starts to stack. But you still should be careful. Using the bow for months this way may limit its lifespan. Especially wood is prone to breaking when you overstretch the limbs. They are simply not designed to be drawn back that far.
Therefore, make sure that you know what the maximum recommended draw length is before you buy a bow.
Do compound bows stack?
Yes, a compound bow can also stack. After the let-off, there is a strong exponential increase in draw weight, which we call the wall. We often don’t call this stacking because this can be configured with the mod.
Stacking essentially means that a bow is overdrawn. This is not possible with a compound bow because the wall will make you unable to draw further. Therefore, I believe we shouldn’t say that a compound bow stacks. Because it has nothing to do with the geometry of the bow.
I might be a bit nitpicky, but we should refrain from using this term too loosely. A bow stacks when it’s overdrawn and that is simply not possible with a compound bow.
How to find out whether your bow stacks
If you want to avoid stacking, you must know how you can spot when a bow stacks. So, let’s discuss how you can spot whether a bow stacks.
I have heard many archers complain that their bow stacks. Some even complain that their bow stack while shooting with a draw length below 28 inches. Although it happens that a bow stacks at short draw lengths, it’s very rare. Stacking often occurs beyond 30 inches, so most archers will never experience it.
These archers complain that their bow stacks but they actually shoot a too heavy draw weight. They feel that the draw weight is too high and blame it on the equipment. This happens often because a lot of archers shoot with a too high draw weight. I think it has something to do with the macho complex around draw weight 😉.
So, don’t say that your bow stacks, just because you can’t comfortably shoot it. Maybe you just need a lower poundage bow.
Some indicators for stacking
As mentioned before, you shouldn’t jump to the conclusion that your bow stacks. Below I have listed down some indicators that your bow might stack
- Limbs bend very far
- The bow is short
- You have a long draw length (30+ inches)
- The bow doesn’t have recurved limbs
So, if multiple of these indicators apply, your bow might stack. But we can’t be certain unless we measure the draw weight. We just can’t trust our muscles as measurement devices. If the bow is too heavy it might like you are drawing 100 LBS. In fact, it might just be a few LBS heavier than you can comfortably draw.
Test whether your bow stacks
So, the only way to figure out whether your bow stacks is to measure it. I have done this with two completely different bows. My long competition-style recurve bow and a short cheap beginner’s bow. I have measured the draw weight between 20 and 32 inches with a one-inch interval. I have taken multiple measurements to decrease measurement error.
You can do this with your own bow aswel. Just use a bow scale (or alternatively a luggage scale) and measure between 20 and 32 inches with a one-inch interval. Plot the data in a graph and you can easily see whether your bow stacks. Read this article for more tips on how to measure draw weight.
As you can see my 70-inch recurve bow has no stacking at all till 28 inches. Only after 28 inches, it will start to stack lightly. That doesn’t surprise me because I have a 31-inch draw and can comfortably shoot this bow.
These limbs are rated as 22 LBS, while the actual draw weight is 25 LBS at 28 inches. This shows that you can’t compare draw weights with other archers just by looking at numbers on the limbs. The draw length and the tiller configuration can significantly change the actual draw weight.
Cheap ‘’beginner's’’ bow
Looking at the draw graph of the beginner's bow; we can see that his bow has some extreme stacking at the end. It starts at 27 inches and becomes extreme at 29 inches. But if we look at the bow it’s no surprise. The bow is only 64 inches and has small recurves, so if this bow wouldn’t stack at 32 inches no bow would.
Only the extremely short brace height helps reduce stacking. But that causes some nasty hand slaps if you draw it beyond 26 inches.
So, to conclude, you don’t want your bow to stack. It’s not a matter of preference. When a bow stacks it will perform worse and may cause damage to the bow. Therefore, you shouldn’t use a bow that stacks at your draw length.
But just because you can’t comfortably draw your bow, doesn’t mean that your bow stacks. It might indicate that you just must decrease the draw weight. If you are uncertain whether your bow stacks, you might want to measure the draw weight at different draw lengths. You can use a bow scale or luggage scale to do so.
If you have any questions or comments please leave them down below. I will reply to your question as soon as possible and send you an email notification. Keep reading to learn more about archery, by reading one of the articles below: