A good compound bow is a beautiful and functional piece of engineering. But if it’s not tuned properly, it’s just a mantlepiece. Fortunately, tuning a compound bow is something anyone can learn to do, even as a beginner.
The process looks complicated at first glance, but don’t let it overwhelm you. Take it one step at a time, and you’ll be an expert in precision compound bow tuning in no time.
Before you begin, a general tip: Take pictures of anything and everything you plan to take apart before you start. You’ll need a reference when you put your bow back together.
Compound Bow Tuning in 7 Steps
Step 1: Order a Bow That Fits Your Specs
Even before you start tuning a compound bow, it should be comfortable to draw and aim. So, make sure the bow you order has the right draw length, draw weight, and let-off percentage for you.
At full draw, your elbow should align with your arrow, and your hand with the release in it should rest along the back of your jawbone. You’ll know your bow has the proper draw weight if you can pull it smoothly without raising it too high (aka sky drawing), changing your position, or aiming toward the ground as you pull.
When you get your bow, make sure the brace height and axle-to-axle (ATA) length match the factory specifications.
Axle-to-axle length is the distance between the centers of the top and bottom axles of your compound bow. Brace height is the area of space between the deepest part of your bow’s grip, the throat, and the bowstring.
These two measurements should be set to your bow’s advertised factory specs. If they aren’t, adjust them before you proceed. This could mean adding twists or taking twists out of your bow’s cables.
Step 2: Set the Arrow Rest
Your arrow rest should sit around 13/16″ away from the bow’s riser. Some can be slightly closer or farther, but this is a general rule of thumb with most modern compound bows.
Start by securing your bow. I recommend a bow vise for this, but anything can work as long as your bow is secure, level, and vertical.
Follow the manufacturer’s instructions to attach your arrow rest to your bow. It doesn’t need to be perfect yet; we’ll adjust it as we move on.
Step 3: Find Your Nocking Point
The center of your arrow should go straight through the center of your Berger hole, with the arrow rest in the upward position.
Check the vertical level of your nocking point by using a 90° bow square. Once you’ve confirmed a 90° angle, tie soft knots above and below the arrow using serving material. I typically do three ties below the nock and three ties above the nock.
Once those are tied, wiggle your nock slightly to allow the slightest bit of room between both soft knots and your nock. This is to prevent nock pinch, which can cause inconsistencies in arrow flight.
Next, you’ll need to tie your D loop in. If you’re right-handed, the top knot should face away from you, with the bottom knot facing toward you. For left-handed shooting, do the opposite.
Your nock should spin freely without the string twisting. Test your setup by pulling on the string gently and letting go. The arrow should come off the string for you to catch. If the nock twists your string or the arrow doesn’t come off the string easily, then you’ll need to remove your center serving and serve a new one in using thinner center serving material.
Step 4: Verify the Cam Timing
The best way to check cam timing is by using a draw board. You’ll need to put your grip of the bow against the peg in the draw board and attach the S hook to your D loop and safety rope around the nocking point. Then, crank it back until just before the cable stops touch your bow’s cables.
Make sure both the top and bottom cams hit the draw stop at the same time. If they do, proceed to the next step. If not, we’ll have to do a little extra work.
If the top cam hits the draw stop first, press the bow, take off the cable on this cam, and add a twist to it to make the bottom cam hit the draw stop at the same time as the top. If the bottom cam stops first, do the opposite. Then, test the cam timing again in the draw board.
Continue this test-and-fix process until both draw stops hit at the same time. Keep in mind that adding twists increases draw weight, while taking twists out decreases it.
Step 5: Paper Tune
Now that you know a little about tuning a compound bow, it’s time to test your work.
Paper tuning is a favorite testing method of bowhunters everywhere. Start by hanging a stretched piece of paper in front of a target. You can do this by taping it across a cardboard box, building a wood frame to attach it to, or taping it inside a chronograph.
Position yourself five to seven feet away from the paper and shoot your arrow straight through and into the target behind. The target should be far enough away that your arrow can completely clear the paper.
Shoot with good form during this stage; if you’re sloppy, you may get misleading results. If you can’t get consistent results, you may need to work on your grip, form, release, and/or facial pressure.
The goal is to achieve a near-perfect “bullet hole” in the paper — the same diameter as your arrow. The more similar the hole is to your arrow, the better its flight. Shoot multiple shots until you have a good idea of what needs to change:
- Nock left: For a big tear, shim the cams to the right. For a small tear, micro-adjust the rest to the right. This also could mean your arrow spine is too weak. You can either go to a stiffer-spined arrow, or you can decrease your draw weight by taking one or two full turns out of both top and bottom limb bolts.
- Nock right: For a big tear, shim the cams to the left. For a small tear, micro-adjust the rest to the left. This could mean that your arrow spine is too stiff. You can go to a weaker spined arrow.
- Nock high: Bring the nocking point down and/or the rest up.
- Nock low: Vice versa.
Step 6: Broadhead Tune
If you’re a bowhunter, then broadhead tuning will be an imperative step to achieving perfect arrow flight. While most broadhead manufacturers state that their broadheads fly like field points, that isn’t true. Some do fly better than others and require less tuning time, but you still need to shoot them and make necessary adjustments.
Shoot one or two arrows with your broadheads of choice with a couple arrows with field points. I’d strongly recommend shooting the broadheads first due to the chance of hitting your other arrows and ruining them. You want the broadheads and field points to have roughly the same point of impact at multiple distances. Once you exceed 60 yards, though, your broadheads will have noticeably more drop because of drag.
You can achieve the same point of impact by moving your rest the opposite direction your broadheads are hitting relative to your field points. If your broadheads hit to the right, move the rest to the left, and vice versa.
Your fixed broadheads may take more time to tune than mechanicals, but you still need to tune both for the best results.
Compound Bow Tuning: Enjoy the Accuracy
Now that you know all about tuning a compound bow, you’ll likely enjoy greater accuracy during your next season and be confident in your setup. What will you hunt first with your freshly tuned bow?
by Brayden Cooney, valued MKC Team Member
