How to adjust the draw length of a compound bow

On recurve bows, you can draw the bow as far as you want. But on compound bows, you must configure the bow to your draw weight. Otherwise, the let-off will kick in too late or too early. If you have bought your bow in an archery store, they probably already did this for you. But if you ordered it online, you will have to do this yourself.

On most compound bows, you configure the draw length by changing the position of the mod. The mod will have markings that indicate the draw length settings. Remove the screws and turn the mod to the required setting to configure the draw length.

Although this is the most common system, there are compound bows where you configure the draw length differently. In this article, I will explain these different systems so you can use this guide for any compound bow. I will also discuss how you can fine-tune your draw length and give some additional tips.

How adjustable drawn length works

Before I explain how to adjust the draw length on any compound bow, it might be helpful to understand how this works. If you know how it works, it will be easier to figure out how it works on your specific bow.

The draw profile and thus the draw length of a compound bow is determined by the mod. You can see how this works in the video below. When the string hits the flat part section of the mod, the bow is at its maximum draw length.

 

To make the draw weight shorter, this needs to happen earlier in the draw. This can be done by changing the position of the cam or where the string or cables are attached. Other bows have replaceable mods or cams to achieve this.

If you want more information on how compound bows work, I recommend reading the article below. It will be much easier to figure out how your bow works if you fully understand the mechanics of a compound bow.

How does a compound bow work

How to adjust the draw length

As mentioned earlier, there are multiple ways to increase or decrease the draw length. Knowing which system your bow has is the first step to configure the draw weight. Below, I will discuss these systems in more detail.

Most modern bows will have either a configurable or replaceable mod. The first option is especially popular for budget compound bows. If you have an older bow, it could also have replaceable cams or adjustable string posts.

Configurable mods

If you have a bunch of holes in your mod with corresponding numbers or letters, you have a configurable mod. To configure the draw length, you must loosen the screw(s). When you have removed the screws, you can twist the mod.

Some mods have the exact draw length printed on the mods. For example, 16 - 31 Inch but others will use a code. You can find what draw length corresponds to each code in the owner’s manual. If you can’t find the owner's manual, you can always try to change the mod in one direction to see what happens.

If both of your cams have a mod, you will have to configure them both to the same setting. Make sure to tighten the screws. Due to vibration screws can easily come loose when you shoot the bow. I have lost a set of screws this way.

Replaceable mods

A lot of high-end bows have replaceable mods. To change the draw length, you must remove the current mod and replace it with a different mod. Some compound bows will come with the different mods in the box. But you often buy them separately. In most cases, this will cost you about $10 to $30.

The owner’s manual or the manufacturer's website often lists what mod you need for what draw length. On most bows, you can do this without a bow press. But if the cables rest on the mod, you need a bow press before you can exchange the mod.

Just remove the current mod by loosening the screws and attach the new mod to change the draw length. If you have two mods, you must replace both.

Replaceable cams

Replaceable cams are uncommon on new bows, they are primarily found on older compound bows. To change the draw length, you must replace the full cam. Since the cables and the string are attached to the cams you will need a bow press to do this.

If you don’t have a bow press, I would highly recommend buying one. If you ever need to replace or work on the string or cables you will need this device. This is the bow press I like to use while I work on my bow.

Replacing the cams can get quite expensive, depending on the brand it might cost you between $50 and $200. Which cams you need for your bow are listed in the owner’s manual, or the website of the manufacturer.

Adjustable string or cable posts

Some old bows have adjustable string or cable posts. If you have a lot of screw ports near the string or cable post, you probably have this system. To adjust the draw length, you first put the bow in a bow press and remove all tension from the string and cables.

You can then start to untwist the string or cable post. Then screw the post in a different port and attach the cables or string to the post. The entire procedure is relatively straight forward, but it might take a few tries to figure out which screw port you should use.

How to interpret the codes on the cam

Configurable mods and adjustable string posts often label the different screw ports. In some cases, they are numbered between 16 and 31. This is the draw length of the bow. If you don’t know your draw length, you can read this article to measure it. Alternatively, you can also start at 28 (the most common draw length) and decrease or increase when needed.

Some compound bows have labels like: A, B, C or 1, 2, 3. These labels also refer to different draw lengths. You can find out what these mean exactly in the owner’s manual. If you can’t find an owner’s manual you can also experiment to find out at which setting it should be.

Dual vs single cam bows

Most bows have two cams and two mods. This means that you must adjust both mods to configure the draw length. Make sure to check that both mods are in the same setting before you fire the bow.

Some compound bows have a single cam setup. This means that your bow only has one mod. The other cam is often called an idle cam or wheel. Compared to the ‘’active’’ cam, the idle cam is completely round.

Just remember this: ‘’if you have two active cams, you have to adjust the draw length on both cams’’

Dual cam compound bow
Single cam compound bow

Limb or draw stoppers

Most compound bows have no limb or draw stoppers. But if your compound bow has these features you must configure those as well. How to do this depends on the specific bow you shoot. Therefore, you need to consult the owner’s manual for more information on how to configure the limb or draw stoppers.

Luckily, most archers don’t have to worry about this feature. If you notice that you can’t get your bow to full draw, while you followed the guide thus far, it’s probably an issue caused by the limb or draw stoppers.

Finetuning the draw length

Most compound bows are configurable by a one-inch interval. This means that you can configure your draw length to 28 or 29 inches, but not 28.5 inches. For most archers that isn’t an issue since an inch isn’t that much. But more experienced archers might want more flexibility.

Luckily this is possible, but it does require a bow press. You first must but the bow in the press and release the tension from the string and cables. Then you add twists to the bowstring to shorten the draw length or remove twists to increase the draw length.

You shouldn’t add or remove too many twists. You only want to use this method for finetuning. If you add or remove too many twists, the bow will shoot less efficiently and stable. I would only add or remove about 10 or 15 twists as a maximum.

Tips while adjusting the draw length

You must adjust the draw length right. If you do it wrong, it can cause damage to the bow. Below some additional tips for when you are adjusting the draw length

  • Be careful with the screws: make sure to keep hold of the screws, if you lose them, you can’t lock the mod back in place. It can be rather difficult to replace them if they are gone.
  • Consult the owner’s manual before you start: if you have an owner’s manual you want to read it first before you start. Although compound bows all rely on the same technology, there are slight differences that can change the process enormously.
  • Be careful while drawing the first time: make sure to double-check whether everything is configured correctly before you draw for the first time. If you for example forgot to configure both mods, the bow might derail while you draw.
  • When in doubt, visit a pro shop: if you are not sure whether you are configuring your bow correctly, you should visit a pro shop. Some advanced compound bows require a lot of expertise to configure.

How to choose the right draw length

Now you know how to configure your draw length, you might also want some guidance on how to pick the right draw length. In the article below, I discuss 4 ways you can use to choose the right draw length.

How to choose the right draw length

Since that article is written for recurve archery, you should subtract one inch from the final measurement. This is because the D-loop and the release reduce the total draw length by about an inch.

You can of course also experiment a bit with your draw length. Your draw length might slightly change. Generally, most archers will slightly increase their draw length when they get more experienced.

You should have both your arms and back straight, while at full draw. If that isn’t the case, you want to increase your draw length.

Final words

Configuring the draw length can be quite difficult because it depends on the system your bow has. Therefore, if you have any issues with configuring the draw length, please let me know. I would love to help you.

Just send me a picture of the bow and a closeup of both cams to [email protected]. I am sure that we can figure out how to configure your bow!

If you have any questions, comments, or suggestions, please leave them in the comment section down below. I will respond to any questions as soon as possible and you will receive an email notification once I replied.

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