Rangerexpert is audience-supported. When you buy through links on this site, we may earn an affiliate commission that we use for site maintenance. Learn more


How to Adjust Draw Length on A Compound Bow?

How to Adjust Draw Length on A Compound Bow
Written by Catherine Weeks
Last Update: August 11, 2023

When shooting an arrow, every archer wants to make the perfect shot. Having the correct draw length helps ensure your shot is accurate.

But do you know how to adjust draw length on a compound bow? Well, that’s what we’re here to discuss today!

Here, we will calculate the draw length, learn the tools for adjusting, and then how to adjust the draw length on a compound bow using the information.

Adjusting Draw Length on Compound Bows: How it Works

The mod will determine the draw length when the flat part section is hit by the string (the bow is now at maximum draw length.)

By changing the placement of the cables or strings and the cam’s position, you can create a shorter draw weight.

Some bows may have replaceable cams and mods that get this job done.

Modern bows may have a replaceable or configurable mod but you can also have adjustable string posts or a replaceable cam on your older bow.

Cam Types

Adjustable Cams

Adjustable cams are perfect for young archers who will need to increase their draw length as they get older and newbie archers who are still figuring out their ideal draw length.

Using an Allen wrench (and pressing the bow), the archer can adjust their draw length from 3 inches to 13 inches on some compound bows.

Draw Length Specific Cam

A draw-length cam bow offers multiple draw lengths using a specified cam.

It requires purchasing an alpha/numerical marked cam and installing it. This task can be daunting due to its complexity.

If you feel you can’t do this, have a pro shop do it for you; it will be $70 to $90 well spent, and ensure the job is done correctly. It is all about safety!

Modular Cams

Modular cams accommodate archers of every size with a draw length that is specific for interchangeable modules.

The change is done without pressing the bow, using an Allen wrench.

The cost is between $8 to $25. This is currently the most familiar cam.

What You Will Need

  • Tape Measure
  • Allen Wrench
  • Calculator
  • Bow press if needed
  • A helping hand

How to Measure your Draw Length

If you are still confused about what your draw length actually is and how to measure one, follow along.

The process of measuring draw length is pretty straightforward. Here are the steps required:

  1. Ask someone to help you in the process
  2. Find a measuring tape
  3. Stand up straight and spread out your arms beside
  4. Hold that position and let your helper take the measurement
  5. The helper should measure your entire wingspan, from one fingertip to another
  6. Divide the measurement by 2.5; the result will be the perfect draw length for you.

How to Adjust Draw Length On a Compound Bow?

Replaceable Mods

The more expensive bows have a replaceable mod. Replace it with a new mod to change the draw length. These cost $10 to $30 and are sold separately.

If there is a cable resting on the cam, you will need a bow press. Check the manufacturer’s guide and the owner’s manual to determine what you need to change.

Be sure to loosen up the screws and change the draw length by replacing the mod and retightening the screws.

Configurable Mods

These have holes with corresponding numbers that represent a draw length. Some bows have a code. Using the owner’s manual and the code, you can determine the draw length.

You can try and dial the cam in one direction and see if you can find your draw length if you can’t find the owner’s manual. If you have two cams, they will both need configuring.

Make sure to retighten the screws when you finish, so they don’t come out with the bow’s vibrations and get lost.

Replaceable Cams

You will generally find these on older bows; the entire cam changes to adjust the draw length.

In addition, you need a bow press because the cables and strings are attached to the cam. So be sure and purchase a bow press; it will be handy when your strings and cables need replacing.

Check the manufacturer’s list and owner’s manual to ensure you have the correct cams; these cams are anywhere from $50 to $200.

Cable Post or Adjustable String

The cable posts and strings are a telltale sign that you have this cam. Before adjusting the draw length, place the bow in the press, relieving tension from the strings and cables.

This process is pretty self-explanatory; you need to unscrew the cable post or string, move it to another port, and then reattach the strings and cable posts.

It may take more than one try to get the right port.

How to Finetune the Draw Length

Now that you know how to change the draw length on a compound bow, it’s time to figure out how you can fine tune your draw length.

A draw length of 29.5 isn’t a big deal to most archers, but someone looking for an exact draw length will want just that.

Once you place the bow in the press, the cable and string tension can be released to decrease the draw length by twisting the strings and cables.

You can increase the draw length in the same way. You are only finetuning, so no more than 10 to 15 twists are needed.

Cam Code Interpretation

You will need the owner’s manual to help decipher the code numbers on the adjustable string posts and the configurable cams.

The draw length is represented by numbers usually between 16 to 31.

However, the most common draw length is 28; this is a good place to start if you can’t find your owner’s manual. Some bows use an A, B, C, or 1, 2, 3 on their cams.

Choosing a Limb or Draw Stoppers

You will need an owner’s manual to configure the draw stoppers or limbs. Most compound bows do not have this feature anymore, but if you do, they need configuring too.

* If you have everything above and still can’t get your bow to full draw, this is probably the issue.

Single Cam Bows vs Dual Bows: Differences

If your compound bow has two active cams…they both need adjusting.

To configure the draw length, both have to be configured. Make sure you don’t fire your bow before checking that both mods are adjusted to the same setting.

One is a compound bow with one mod; the second may be called the wheel or idle cam (it is completely round).

How to Set Draw Length on Compound Bow: Pro Tips

Try the Armspan method

Spread your arms out (in a “T”) at shoulder height, and have someone measure from the fingertip on the left to the fingertip on the right from the back.

Take that number and divide by 2.5; this is your draw length.

As an example: if your draw length is 32, 32/2.5 = 12.8 is your draw length.

Before starting, consult the owner’s manual

Even though bow technology is the same, some differences can significantly impact the draw length. Be cautious and use the owner’s manual as your guide.

Use caution while drawing the first time

Before you reshoot the bow, make sure you double-check that both mods are configured and the bow is ready to use. No one wants a bow to derail when they draw!

The need for speed

For some unknown reason, men like to set their draw length high. In doing this, they gain some speed but lose comfort and control. For safety reasons alone, you should not do this!

Every form of archery involves the perfect collaboration of physics and biology. Biting more than you can chew will almost always end up in pain or failure.

Gradually work your way up and find the perfect draw length that works for you.

Caution with the screws

Make sure to put the screws in a bowl or hold on to them. You’re screwed (pun intended!) if you lose them; you can’t lock the nod in place without them!

Also, some of those screws are hard to replace.

When to visit a pro shop

When you aren’t sure how to adjust the draw length or have a more complex or new bow, you should have a pro do it for you.

It is worth the money to have an accurate draw length and maintain safety!

About the author

Catherine Weeks

Cathy believes that hunting is not about downing an animal; rather, it’s about enjoying the purity of this challenge and making a connection with nature.

She loves country music, horses, shooting, and hunting; and spends her weekends in the great outdoors with her husband and two kids.

Though Cathy has hunted most of her life, it was not until her partner gave her a bow that she realized she had finally found her passion.

She is always determined to share her missed opportunities, dedication, emotions, and small details that people often forget to mention when they talk about their hunting experiences.

Cathy also works to promote wildlife preservation and protect natural resources. She thinks “patience” is the most important thing that can make a big difference.

Leave a Comment