Essential Guide To Recurve Bow Tuning

October 23, 2014

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Before you get started, make sure that all the items you’ll be using on your recurve bow are installed – things like stabilizers, bow sight, string, quiver, and so on. You want your bow to be as complete as possible because whenever you introduce a new component you will likely need to make some tuning adjustments. This is a critical step that in my experience is often overlooked by archers, particularly those who are only experienced with a crossbow (which typically require very minimal tuning, if any).

Our first step is making sure that all the parts of your bow are properly installed. Let’s start with the nocking point.

Perfect Nocking Point Location

Make sure to purchase a nocking point with your bow as they usually don’t come with the package, unless you are buying an entire recurve bow set with arrows and everything included. When installing the point, make sure it is positioned approximately half an inch above “square.”

Square refers to the imaginary line that extends from the surface of your arrow rest and forms a 90 degree angle with the bow string when in its lose position. You can use a T-square device to measure that precisely, though it can be done with just the arrow if you take your time and do things accurately. See image below:

tsquare

See that red vertical line that I drew? You want to place your nocking point 0.5″ above it. You may need to adjust this ever so slightly, but we’ll get to that later in the tuning process.

At this point it’s worth mentioning that the nock on your arrow should have a proper fit for the nock point on your string. As a rule of thumb, you want the fit to be tight enough so that the arrow can hang freely from the string, with the nock/nock point being perfectly capable of supporting the arrow’s weight. At the same time, the arrow should be able to disengage if the string is given a strong tap (with your hand) a few inches away from the nock.

Don’t let this distract you; many people spend months upon months researching the perfect arrows before they actually buy their recurve. Yes, the type of arrows you use is really important. But it is also certain that no amount of research you do will actually help you choose the “perfect” arrows for your bow; only practice and time will help you determine that, as you will never know what the ideal arrows are before you get to intimately understand the behavior of your particular bow. So my advice is to simply get one or two different types of quality arrows, try them out with your recurve bow, see how accurate they are, and then try to improve from there once you gain some practical archery experience. Any other approach is just a waste of your time.

Micro-Tune The Brace Height

By brace height we simply mean the distance between the deepest part of the bow riser, and the string in its loose position.

brace height

The vast majority of recurve bows have a brace height somewhere between 7.5 and 9.75 inches. The brace height of your bow will dictate some of its behaviors, such as how loud it shoots and how much pivoting your arrow will experience mid-air. On most recurves you’ll be able to adjust the brace height by up to 1/2″ in both directions (either increase it or decrease it). How do you do that?

By twisting the string as you string your bow. The more twists you add at the tip of the string, the more more “flexed” it becomes, hence pulling the limb tips slightly away from the riser and increasing brace height. Similarly, if you want to decrease the brace height, you will reduce the number of twists on the string. The instruction manual that came with your recurve bow will include the manufacturer’s recommendation as to an acceptable brace height range.

Your goal is to twist and untwist the bow string until you reach a brace height that results in the least noise and vibration when an arrow is shot. It’s a good idea to ask someone to stand next to you and tell you when the bow is being the most quiet, as it can be difficult for the archer shooting the bow to judge this properly due to very close proximity to the string.

Step by step:

Simply string your bow, measure the brace height using a ruler, shoot 10 or so arrows, then adjust the brace height by 1/8 of an inch up or down by adding or removing a few twists. Make sure to measure the exact brace height after every change made, note it down, and assign each setting a subjective “noise” rating based on how loud it tends to be when shooting the arrows. At this point don’t worry too much about your shooting accuracy.

Once you’ve found the ideal brace height (which will differ depending on your bow, string materials, and type of arrows you’re shooting), it’s best to write the exact height in inches onto the inside of the limbs of your bow, using a permanent marker. This is a very important value and you want to always have it available “on hand.”

Note: ideal brace height varies from bow model to another, and can even vary slightly across two different bows of the same make and model. You should therefore never rely on another person’s suggestion regarding the brace height to use, and always follow the procedure above to determine the appropriate height for your setup.

 

Centering Your Arrows

As you release the bow string from your fingers, the arrow will tend to “wiggle” to the left and right as it clears the arrow rest. This is what causes archer’s paradox, and it can be clearly seen in action on the 11 second slow-motion video below:

Our goal when centering the arrows is to kind of “make up” for this bending motion that occurs on release of the string. Otherwise our arrow would land too far to the side of where we were actually aiming, even if we had the arrow point or sight aligned for the bulls-eye perfectly.

To center your arrows, you will need to adjust the cushion plunger or your bow’s arrow rest assembly, so that when you draw the bow, the precise center of the arrow point is positioned around 1/12th to 1/8th of an inch to the outside of the string, when looking at it from directly behind the string itself.  Take a look at the artistic image I drew below:

centering arrows recurve bow

Assume that the image above represents what you see as you draw your bow, and if you were to look from precisely behind the string. The red line represents the string, the black line is the arrow rest, and the little green line is the point of your arrow. See how that point protrudes slightly (1/10″) to the outside of the string? It isn’t positioned 100% perpendicular to the string, otherwise the tip of the arrow would not have been visible from this angle (the string would have obstructed our view of the arrow point). Here is another view:

centering arrow recurve bow second

The image above shows what we would see if looking at a drawn bow from an overhead view. The red dot is the tip of the string (I couldn’t figure out how to represent that, other than with a small dot), the green line is the arrow pointed at the target, and the black line is the arrow rest. On the image labeled “wrong” you can see that the arrow is perpendicular to the string. On the “right” image though, the arrow tip is pointing a little bit to the left (the outside – on a right-handed bow; for a left-handed bow, it would need to point out to the right) of the string.

This concept can be a little difficult to explain in text or even on video. If it’s still unclear, please take a moment and try to imagine yourself holding a recurve bow and then look at the images above again and see if you can visualize what I’m talking about. It usually helps. Your goal is to adjust the rest’s side loading attachment or the plunger (if you have one) so that the arrow is positioned 1/10″ to the outside of the string.

 

Bare Shaft Accuracy Testing

Now that you have the nocking point installed properly, the right brace height determined, and your arrows centered, we need to take a look at how your arrows are flying and how they hit the target to determine if further tuning is necessary, and if you should get different arrows for optimal performance with your setup.

To do that, you will need a few fletched arrows, as well as few bare shafts – the arrows without the fletchings. You can get some cheap bare shafts online, or you can just get regular arrows and remove the fletchings manually, thereby making yourself a bare shaft.

Porpoising

This is the first thing we’ll be looking for. Porpoising happens when the arrow alternates between rising and “submerging” relative to its intended flight path. The image below demonstrates this in action:

Porpoising

Side View

It’s called “porpoising” because the arrow behaves mid-flight almost like a porpoise (a mammal from the dolphin/whale family) does in water. If your arrow behaves as shown on the image above, this means that the location of your nocking point needs adjusting. Here is how to carry out the bare shaft test to solve this issue.

Step one: place a target 20 yards away and, aiming for a certain location, shoot two or three fletched arrows.

Step two: standing at the exact same distance from your target and aiming for exactly the same location as before, shoot two or three unfletched (bare shaft) arrows.

Now approach the target and take note of where your arrows landed exactly. There are two things to consider:

  1. If the bare shafts landed higher than the fletched arrows on the target, this means your nocking point is installed too low on the string. You will need to move the nocking point a little higher (start with 1/8″), and then repeat the two-step bare shaft test described above. Keep adjusting the height of your nocking point and testing until both your fletched and un-fletched arrows land at exactly the same height on the target. 
  2. If the bare shafts landed lower than the fletched arrows, then the nocking point is positioned too high, and you will need to move it down the bowstring until both your fletched and un-fletched arrows land at exactly the same height on the target.

For this test to work, it is imperative that you always aim for the exact same spot when shooting the fletched arrows and the bare shafts; that you stand at precisely the same distance from your target each time you shoot; and that you use the exact same draw/aim/release technique.

The goal is to make sure both the fletched arrows and the bare shafts (unfletched arrows) land at exactly the same horizontal plane.

Below are images illustrating the above:

Porpoising nocking point tuning

Important Note: at this point, you do not need to worry about both your fletched arrows and bare shafts landing right next to each other. You simply want both of them to land in the same horizontal plane, as this will mean you have successfully tuned your bow to avoid porpoising. For both fletched and unfletched arrows to land right next to each other, however, you also need to make sure that they are not fishtailing.

Fishtailing

Fishtailing is kind of the opposite of porpoising, where rather than the arrow dipping up and down mid-flight, it will turn right and left. The image below illustrates this (pay attention to image caption):

Fishtailing

Overhead View

To diagnose and fix fishtailing, do the following:

Step one: as before, place a target 20 yards away, aim for a specific location and shoot two or three fletched arrows.

Step twousing the exact same distance and aiming for the exact same spot on the target, shoot two or three unfletched (bare shaft) arrows.

Approach the target and take a look at where your arrows landed.

#1: If bare shafts hit the target noticeably to the left of the fletched arrows, it means your arrows have a stiff spine. Do one of the following, depending on your options:

  1. Reduce the tension on the plunger spring or move the rest assembly closer to the riser, thereby re-centering your arrows and moving the arrow points closer to the string.
  2. If your do not have a plunger or a rest assembly, you can address the issue by using heavier arrow points than what you are using. Say if yours are 100 grain, you can try 125 grain.
  3. Try increasing the brace height a little and see if that helps.
  4. If none of the above options seem to help, it likely means that you need to get arrow shafts with less spine/stiffness than your current ones.

#2: If your bare shafts hit the target noticeably to the right of where the fletched arrows impacted, it means your arrows have a weak spine. Do the reverse of what you did above:

  1. Increase the tension on the plunger or move the rest assembly further from the riser so as to re-center your arrows and move the arrow points further away from the string.
  2. If the above is not possible, get slightly lighter arrow tips and see if that helps.
  3. See if decreasing the brace height of your bow by 1/8″ – 2/8″ will help.
  4. If none of the above tweaks help despite your efforts, it means that you must get new arrow shafts with more spine/stiffness than what you have right now.

Please note: I created the images below assuming that you are using a right-handed bow. If you’re a “leftie,” everything will be reversed; unfletched arrows landing too far to the left will indicate weak arrow spines, while unfletched arrows landing too far to the right will indicate a stiff spine.

Fishtailing arrows

The goal at this point is to make sure that your arrows land as close to each other as possible, by making the necessary tuning adjustments and changes as described above.

 

Proper Clearance

Clearance refers to the arrows capability to “clear” the bow without the fletchings on the arrow making direct contact with the bow. Improper clearance significantly reduces shooting accuracy and results in poorer arrow grouping, so it’s very important that we address it.

First, we’re going to need to determine if and where clearance issues are occurring. To do that, you will need one of the following:

  • Dry foot powder (for Athlete’s foot); a good and cheap brand is Dactarin.
  • Talc
  • Dry deodorant (the kind that leaves annoying white stains on your clothes)

Try not to use dry foot powder in a can, as the layer of powder it creates is way too thick, making it useless for our clearance test and also annoyingly difficult to wash off. What we’re going for here is a substance that will stick firmly to your bow and arrow (more on this in a moment), though not so firmly that no trace would be created if you were to glide your finger across the substance. The substance also needs to be clearly visible to the eye (non-transparent).

Say you decide to go for the dry deodorant. You will want to apply a generous layer to the following areas:

  1. The part of the arrow shaft between the nock and the fletchings (though not the nock itself as this won’t help)
  2. The fletchings
  3. Two inches of the arrow shaft below the fletchings
  4. Arrow rest

Now go ahead and shoot a fletched arrow, while being careful not to disturb or touch the layers of substance you applied when drawing, aiming and shooting. Release the arrow, but make sure you are aiming at a hefty-enough target that’s capable of stopping your arrow without the fletchings digging into it. The next step is examining whether there are any visible markings that have appeared on the layer of dry deodorant.

  • The most common problem is arrow fletchings not clearing the rest properly. This will be clearly identifiable thanks to the “skid marks” on the rest and the fletchings themselves. To fix this, begin rotating the nock on your arrow in the smallest increments possible, making sure to re-do the test after each nock adjustment. Repeat this as many times as possible until the fletchings achieve proper clearance. 
  • If the above doesn’t help, you should try some lower profile fletchings, such as the parabolics.
  • Make sure that you’ve completed the bare shaft test, and particularly that you’ve fixed any porpoising issues you might have had, as an incorrectly installed nocking point can reduce the fletchings’ capacity to clear the arrow  rest.
  • As a last resort, try and re-center your arrows so that the arrow point becomes positioned even further to the outside of the bowstring. This will likely cause the arrows to fly a little stiffer, however that’s better than shooting an arrow that does not clear the rest properly.

What If Nothing Works?

While the above will solve clearance problems in the vast majority of cases, sometimes nothing seems to work. In which case, the most important thing to ask yourself is this: is the fletchings’ inability to properly clear the bow having a negative impact on my archery shooting experience ?

Sometimes it’s easy to get caught up trying to fine-tune everything to absolute perfection, and this can make us forget the real reason we’re doing it – so that we can shoot more accurately and have more fun while doing it. There are cases were theory seems to be screaming “This Should Not Work!” but for some reason it does work, and works just fine. So just because you notice smudges on the dry deodorant does not always mean that your accuracy will be affected; if you are consistently shooting tight groups at 30, 40, 50, 60, or whatever other distances you think you should be doing fine at, then it means your bow setup is tuned just fine (though theoreticians will disagree of course :).

If despite all of the above you still feel that you’re not getting the most out of your bow and you strongly believe it is a clearance issue, please leave us a comment below describing the type of tuning you’ve done so far, and we’ll do our best to help (we monitor comments daily).

 

 




Martin Douglas
Martin Douglas

Author



2 Responses

Randy Johnson
Randy Johnson

October 01, 2015

Nice guide, it lead me from basic to advance and i learn so much about Recurve Bows, if it can, may i use your guide for my blog?
Randy

SILVIO TROMBIN
SILVIO TROMBIN

October 24, 2014

Thanks a lot, well done. Clear and concise. Bye

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