Easton Archery EASTON TUNE User Manual

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ID

TUNING

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A

A

C

C

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2 Arrow Tuning and Maintenance Guide

INTRODUCTION

Successful tuning can only be achieved by using a prop­erly spined arrow shaft. Start with a shaft recommended
on Easton’s Arrow Shaft Selection Chart, available on the
Easton web site at www.eastonarchery.com, in the Easton
Target and Bowhunting catalogs, and on the Easton Shaft
Selector “Plus” software program. Final verification is
achieved during the tuning process. Problems caused by
an improperly spined shaft will become evident during
tuning. Before tuning, be sure that shafts are straight,
properly fletched, and have perfectly aligned nocks.

Choose Your Shooting Style.

Tuning procedures for the three most popular shooting
setups are described and abbreviated throughout this
guide as follows:

◆ recurve bows, using finger release (RF)

◆ compound bows, using finger release (CF)

◆ compound bows, using a release aid (CR)

Some of the techniques of bow tuning apply to all types of
bow setups and others apply to just one or two types.
When separate tuning procedures are required for specific
setups, find your setup within the topic and follow those
specialized instructions.

Install All Accessories

Before starting any bow tuning, be sure to install on your
bow all the items you intend to use when shooting. This
includes the correct bowstring, bow sight, stabilizers,
arrow rest, cushion plunger, bow quiver, etc. Any adjust­ments made to the bow or changes in bow components can
affect the tune of your equipment. Remember, when tuning,

it is very important to change only one variable at a time!

The first phase in achieving well tuned equipment is good
preliminary equipment setup. If the initial setup is done
correctly, bow tuning can be an easy process. By following
the bow setup guidelines in the initial preparation of your
equipment, you can eliminate most or all of the possible
disturbances that cause tuning problems, including false
tuning indicators. An example of a false tuning indicator
would be having a high nocking point indication when the
problem is actually poor clearance.

Install the Nocking Point

Install a moveable nocking point on the bowstring. Clamp­on types are ideal. Initially, position the nocking point on
the bowstring about 1/2" (1.3 cm) above square for RF and
CF and approximately 1/4" above square (0.63 cm) for CR.
See Fig. 1.

Fig. 1

90°

1

/2" RF, CF

1

/4" CR

Nocking
Point
Position

Find the Limb Centers

In order to have a reference point from which to adjust the
arrow's left/right position on the bow, it is necessary to find
and mark the exact center of the limbs on a recurve bow,
or what is termed the “balanced limb center” on a com­pound bow, as defined below.

Recurve Bows

To find the limb center for recurve bows, place a
piece of masking tape across the inside of each limb
near the riser. Measure the width of the limbs, and
make a small vertical mark on the tape in the exact

center of each limb.

Compound Bows

To find the balanced limb center location for the
preliminary setup of your compound bow, place a
piece of masking tape across the inside of each limb

near the riser. Measure the width of the limbs, and
make a small vertical mark on the tape in the exact center
of each limb. Next, measure 3/16" (4.8 mm) to the left of the
mark (for right-handed archers) and make a larger vertical
mark on the tape. (Left-handed archers place a larger mark

3

/16" (4.8 mm) to the right of the limb center mark.) This
second mark will be used for arrow centering. (See Fig. 2.)
This procedure is done to compensate for the amount the
eccentric wheel or cam is offset from the actual center of

Fig.

2

the limb. The 3/16" (4.8 mm) measurement is an average
“offset” difference for most compound bows and does not
need to be a precise measurement in the preliminary setup
stage, as you will locate the true balanced limb center
when performing the fine-tuning procedures.

Compound Bow
Balanced Limb
Center Location

Actual
limb center
(right mark)

Balanced
limb center
(left mark)
Measured 3/16"
from actual
center

Wheel
Bow limb

Tape

Tape

Bow limb

Wheel

“Centering” the Arrow

The objective of arrow centering is to have the arrow leave
the “theoretical” or “balanced” limb center of the bow. In
actuality, it is the two nodes (Fig. 3) of the arrow shaft that
should leave the center of the bow in direct alignment to
the target. Releasing the string with fingers creates a
horizontal bending motion within the arrow. Releasing
the string with a release aid causes a slight up/down
bending motion. Because of this, the arrows must be
positioned differently for each style of release. Adjust the
horizontal (in/out) position of the cushion plunger or
arrow rest assembly so that the tip (center) of the arrow
point is correctly aligned with the type of equipment you
shoot. (See Node Alignment diagram to the right).

Tuning—Bow Setup

3

Aligning the Nodes

Fig. 3 Nodes

Arrow Nodes - As the arrow oscillates, the nodes
remain in direct alignment to the target. This
diagram clearly illustrates the front and rear node
positions of the arrow. The front node is usually
closer to the front end of the arrow than the rear
node is to the nock end. This is due to the mass
weight of the point—nodes will always be located
closer to the heavier mass.

Front NodeRear Node

Direct Line
to Target

Top View of
Arrow

Fig. 4

Finger
Release
(RF, CF)

Line to target Line to target

When there is
no pressure
on the
cushion
plunger, the
finger­released
arrow nodes
are aligned
slightly
outside the
center of the
bowstring.

Fig. 5

Compound
Mechanical
Release (CR)

As the
cushion
plunger
compresses,
the nodes
of the arrow
come in
direct
alignment
to the
target.

Fig. 6

Misaligned Arrow
RF, CF, CR (Incorrect
Arrow Rest Position)

Adjust the Arrow's
Left/Right Position

Adjust the horizontal (in/out) position of the cushion
plunger or arrow rest assembly, so that the tip (center) of
the arrow point is correctly aligned with the type of
equipment you shoot, as described below.

Finger Release (RF,CF)

Align the “tip” of the arrow point 1/16" to 1/8" (1.6-

3.2 mm) or less outside the bowstring with the
bowstring properly centered according to Fig. 7. The
arrow tip is placed slightly outside the string to provide
compensation for the amount the cushion plunger or side
loading device compresses into the bow when the arrow is
released. See Fig. 4.

With a finger release, the arrow bends horizontally, first
bending in toward the bow, then bending away from the
bow, which causes the arrow shaft to leave the arrow rest.
In the next bending sequence, the arrow nock disengages
from the bowstring. The arrow is then on its way, freely
oscillating all the way to the target. The amount of oscillation
decreases as the arrow travels farther from the bow.

Mechanical Release (CR)

Align the “tip” of the arrow point down the
center of the bowstring. See Fig. 5. The center

line (axis) of the arrow must start out in a direct
line with the bowstring when the bowstring is aligned to
the balanced limb center. See Fig. 7.

When using a release, the arrow most often bends vertically,
rather than horizontally. Therefore, there is no need for an
inward compression device such as a cushion plunger.
Follow the bow tuning methods in the Fine Tuning and
Micro Tuning sections on pages 12-14 to find the best
in/out position for your arrow shaft, which allows the
arrow nodes to be in direct alignment to the target.
The diagrams in Fig. 7 indicate the correct in/out arrow
position for your shooting style.

Line to
target

The arrow tip is
aligned down
the center of the
bowstring.
Nodes of the
arrow are in
alignment to the
target. (Since the
arrow bends
vertically when
using a release,
the nodes stay in
alignment with
the center of the
bowstring.)

Bowstring
to target
alignment

Rear node
position

Front node
position

The arrow is
not
positioned
to leave the
center of the
bow—it is
out too far.
Nodes are
not in
alignment to
the target.

Fig. 7 Arrow Centering

Recurve Bow
Finger Release

Arrow
Tip Out

1

/16"-1/8"

Nock

Bowstring
aligned
with limb center

Compound Bow
Finger Release

Arrow
Tip Out

1

/16"-1/8"

Nock

Compound
Bow
Mechanical
Release Aid

Arrow
Tip in
line
with
bowstring

Nock

Bowstring aligned with
balanced limb center

4 Arrow Tuning and Maintenance Guide

Adjust the Arrow Rest

(Recurve and Compound)

The arrow rest support arm position is critical to achieving
good arrow clearance.

Finger Release (RF, CF)

Most flipper/rest setups have an adjustable arm for
the arrow rest. If this adjustment is available on the

rest you're using, the arrow rest support arm should
be adjusted so that it is not visible past the outside of the
arrow shaft when observed from an overhead view. See
Fig. 8.

Mechanical Release (CR)

On launcher type rests, commonly used on
compound bows with release aids, be sure that

the arrow support arm is narrow enough to allow
the two lower vanes to pass over the rest without making
contact. (See the Fig. 9.) This is very important for archers
using release aids because the arrow is most often sup­ported on the rest for its full length of forward travel. For
the smaller diameter aluminum/carbon or carbon shafts
with less space between vanes, it may be necessary to
significantly reduce the width of the launcher blade.

Fig. 8

Arrow Rest - Overhead View (RF,
CF)

Correct Position Incorrect Position

BOW

Arrow rest

NOTE:
Be sure
enough of
the flipper
arm is
extended to
safely hold
the arrow on
the rest.

Fig. 9

Arrow Rest - Back View, Vane Clearance
(CR)

Correct ­Good Vane
Clearance

(out too far)

BOW

Arrow rest

NOTE:
Be sure that the
arrow rest has
enough height
above the
arrow shelf to
allow for vane
clearance.

Incorrect ­Poor Vane
Clearance

Adjusting for Outsert
Components (CR)

When using carbon arrow shafts with externally
fitted nocks, it may be necessary to adjust your
nocking point up slightly to allow the nock to clear

the arrow rest. (The nock diameter is larger than the
shaft diameter.) A slightly higher nocking point lifts the
arrow off of the arrow rest and keeps the nock from
contacting it, eliminating a potential clearance problem.
Internal-fit nock systems do not have this problem.

RISER-MOUNTED CLICKERS (RF, CF)

For shooters using a clicker, be sure that the arrow is well
supported on the rest and not held in place only by the
tension of the clicker. Draw the bow a few times without
the clicker to make sure the arrow can be drawn and let
down without the arrow falling off the arrow rest.

ALIGN THE BOW-SIGHT PIN

Initially, set the sight pin on your bow sight over the
centerline of the arrow shaft.

SET CUSHION PLUNGER

Not every type of bow setup uses a cushion plunger. For
example, many archers use a Springy™ rest, and some
traditional archers use other styles of arrow rests that do
not have side pressure tension adjustments. If your setup
incorporates a cushion plunger, start with the spring
tension set at medium.

Set Brace Height

(Recurve bows)

Start with the brace height at the lower end of the
manufacturer’s recommendation or use the follow­ing chart. To locate the optimum brace height for
your particular bow, “twist up” the bowstring to

make it shorter. This raises the brace height.

BOW LENGTH

64" 8 1/4" - 8 1/2" (21.0 cm - 21.6 cm)
66" 8
68" 8
70" 8

All bows are different, even bows of the same make and
model can have small variations. Therefore, it is important
to locate a brace height that fits your particular bow and
shooting style. Shoot a few arrows at the suggested
beginning brace height, then unstring the bow, add 3-4
twists to the bowstring and shoot again. Continue this
process until the bow feels smoothest and quietest when
shooting.

If the bowstring is too short to allow a brace height at the
lower setting, use a slightly longer string. If the string is too
long to allow a higher brace height (and starts to knot-up
from too many twists), try a slightly shorter bowstring.
There are many custom bowstring makers who produce
strings to your exact specifications including length, type
of material, type and color of serving, etc.

BEGINNING BRACE HEIGHT

3

/8" - 8 5/8" (21.3 cm - 21.9 cm)

1

/2" - 8 3/4" (21.6 cm - 22.2 cm)

5

/8" - 8 7/8" (21.7 cm - 22.5 cm)

Standard Tuning—Bare Shaft Planing Test

5

The brace height determines the specific point at which
the arrow separates from the bowstring and the amount of
bend the arrow has when the separation occurs. The best
brace height for your recurve or compound bow is one that
allows the most compatible launch position for the arrow
at the end of the bow’s “power stroke.” Locating the best
brace height for your bow can significantly improve arrow
grouping and shooting consistency.

Set the Brace Height

(Compound bows)

Brace height is set by the compound bow manufac­turer. Sometimes changing the brace height to a
slightly higher or lower position will improve arrow

flight and grouping. This can be accomplished by
changing the length of the string, as described previously
for recurve bows. Remember, however, that changing the
brace height of a compound bow affects the draw weight
and draw length of the bow.

Nock-to-Bowstring Tension

The nock tension (“snap fit”) necessary to separate the
nock from the bowstring serving can be very critical,
especially on light draw-weight bows (30 lbs. and under).
Nock tension should be tight enough so the arrow can
easily support its own weight when the arrow is hanging
vertically on the bowstring (nock against the nocking
point). To check this, hang your arrow vertically from the
bowstring, and give the string a sharp tap with your finger
on the serving about 1-2" (2.5-5 cm) from the arrow nock.
The arrow should separate from the string. If it does not,
the nock is probably too tight for most target archery. For
hunting, a tighter nock-to-bowstring fit is often preferred.
To accommodate this, Easton designs nocks in several
string groove widths. Easton's Super Nock is designed
with the tight press fit bowhunters need to keep an arrow
on the string in all types of hunting conditions. The 3-D
Super Nocks feature a snap fit with slightly less string
tension, and a nockset détente for shorter bows. The "G"
nock is available in two string groove widths.

Arrows that do not fly well and do not group tightly are
usually affected by one or more of the following problems:

1. They may PORPOISE in flight.

2. They may FISHTAIL in flight.

3. They may not CLEAR the bow properly as the arrow
leaves the bowstring. They may also MINNOW in
flight (a specific type of clearance problem).

1. Porpoising

It is important to correct for porpoising first. If the arrow
leaves the bowstring with the nock too high or too low, a
motion known as porpoising occurs. Porpoising is caused
by an incorrect nocking point location. Use the Bare Shaft
Planing Test to find the correct nocking point location.
Shoot at least three fletched shafts at a distance of 15 to 20
yards (or meters). Then shoot two identically-aimed
unfletched shafts. Once you get the bare shafts to impact
close to the fletched arrows at 20 yards (or meters), you
may want to try shooting 25-30 yards (or meters) for a finer
tuning indication.

If the unfletched shafts impact above the identically­aimed fletched shafts, move the nocking point up on the
bowstring until both fletched and unfletched shafts strike
at the same elevation. See Fig. 10.

If the unfletched shafts impact below the identically­aimed fletched shafts, move the nocking point down on
the bowstring until the unfletched shafts hit at the same
elevation or slightly lower than the fletched shafts.*

To assure you have eliminated porpoising, repeat the test,
shooting first the fletched, then the unfletched shafts, and
make adjustments to the nocking point until both fletched
and unfletched shafts impact at the same elevation.

Fig. 10

Porpoising

Now that you have completed the preliminary adjustments,
you can start the tuning process. Four methods of bow
tuning are described on pages 5 through 14: the Bare Shaft
Planing Test, the Paper Tuning Arrow Test, Short Distance
Tuning, and Broadhead Tuning.

Bare Shaft Planing Test

(Finger release - RF, CF)

In addition to tuning, the bare shaft test is also
useful for determining if the correct shaft has been

selected. If the left/right adjustments outlined un­der “Fishtailing” do not cause the unfletched shafts to
group with or very near the fletched shafts, then a weaker
or stiffer spined shaft (based on where the arrows have
impacted) must be selected.

Nocking point too low* Nocking point too high*

* It is sometimes desirable to have the bare shaft impact just slightly
below the identically-aimed fletched shafts. Bare shafts that impact above
identically-aimed fletched shafts indicate a low nocking point. If the
nocking point is too low, it may force the arrow fletching down into the
arrow rest, creating Clearance problems.

6 Arrow Tuning and Maintenance Guide

2. Fishtailing

If the arrow leaves the bow with the nock end leaning to
one side or the other, fishtailing occurs. The nock end of
the arrow will appear to move from side to side as the
arrow follows its flight path. See Fig. 11.

Use the Bare Shaft Planing Test to correct fishtailing. Shoot
three fletched shafts at a distance of 15 to 20 yards (meters),
then shoot two identically-aimed, unfletched shafts. If the
unfletched shafts impact left (stiff) of the fletched shafts, as
seen in Fig. 11 (for a right-handed archer), either decrease
the spring tension on the cushion plunger, increase bow
weight slightly (if your bow weight is adjustable), or
increase arrow point weight.

If the unfletched shafts impact right (weak) of the identically­aimed, fletched shafts, as seen in Fig. 11 (for a right-handed
archer), increase the spring tension on the cushion plunger,
decrease bow weight slightly (if your bow weight is
adjustable), or decrease arrow point weight.

Your equipment is basically tuned when the bare shafts
and fletched shafts impact at the same or very near the
same location. Once you have completed the finer tuning
methods listed for Fine Tuning and Micro Tuning on
pages 12-14, do not be surprised if the bare shaft impact
changes. It is common on a well-tuned bow to have the
bare shaft impact a little low and slightly stiff (to the left of
the fletched shafts for a right-handed archer). Occasionally,
a good tune may be achieved with the bare shaft impacting
slightly weak (to the right of the fletched shafts for right­handed archers), but this is less common.

When correcting fishtailing using the Bare Shaft Planing
Test, you may have a problem adjusting the unfletched
shaft's impact to that of the fletched shaft. Your arrows
might be too weak (the unfletched shaft impacts to the
right of the fletched shaft for right-handed archers) or too
stiff (the unfletched shaft impacts to the left of the fletched
shaft for right-handed archers). If, after completing this
test, the bare shaft impact is more than 6 inches (15 cm) to
the right (weak) or left (stiff) of the fletched shafts at 20
yards (18 m), you will need to change shaft size, or make
some modifications to the equipment to achieve a better
tune. Follow the suggestions on how to better match the
arrow to your bow in the “Adjusting the Bow and Arrow
System” section on page 10.

Fig. 11

Fishtailing

Stiff Arrow

Unfletched shafts
impact left
(RH archer, opposite
for LH)

Fig. 12

Minnowing

If you are not achieving good arrow clearance, and the
arrow fletching and bow make contact, optimum grouping
cannot be achieved. By examining the areas where the dry
powder spray is scraped off, the nature of any interference
can be determined, and the position of the fletching as the
arrow leaves the bow can be identified.

Minnowing, like fishtailing or porpoising, indicates a
specific arrow flight disturbance. Minnowing will appear
to look much like fishtailing except that the tail of the
arrow appears to move from side to side more quickly, and
the amount of side swing is usually much less than in
fishtailing. (See Fig. 12.) Minnowing indicates inadequate
clearance and is caused by the rear portion of the arrow
(usually fletching) contacting the arrow rest assembly.

Weak Arrow

Unfletched shafts
impact right
(RH archer, opposite
for LH)

3. Clearance

Proper clearance is absolutely essential for optimum group­ing, consistency and accuracy. This is especially true with
ultra-light weight arrows like the UltraLite aluminum, the
A/C/E, A/C/C and A/C/C HyperSpeed shafts.

After you have performed the Bare Shaft Planing or Paper
Tuning Arrow Test, it is a good idea to check for adequate
clearance. To check for clearance, use dry powder foot
spray, dry deodorant spray or similar product, applied to
the last quarter of the arrow shaft, fletching, arrow rest
assembly and sight window near the arrow rest. Do not
disturb the powder sprayed on the arrow and bow while
preparing to shoot. The arrow should be shot into a firm
target so that it will not penetrate to the fletching.

Correcting Clearance Problems

The following procedures can help you correct clearance
problems that cause minnowing:

1. If the arrow fletching is hitting the arrow rest, try
rotating your arrow nock 1/32 of a turn. Continue
rotating the nock in 1/32-turn increments until clearance
is achieved.

2. Make sure your arrow rest support arm does not
protrude past the outside of the arrow shaft when the
arrow is resting on the support arm and is lying against
the cushion plunger or side loading device. See Fig. 8.

3. Choose a lower profile fletching.

4. Follow the procedures for Tuning Adjustments within

Standard Tuning—Paper Tuning Arrow Test

7

the Bow and Arrow System on page 10 for equipment
modifications to achieve a better tune.

5. Move the cushion plunger or side loading device
slightly out from the bow to help increase clearance if
the other tuning modifications have no effect.

Paper Tuning Arrow Test

(Recurve or compound - RF, CF, CR)

Archers using mechanical release aids (CR) should review
the following reminder notes before starting the Paper
Tuning Test.

1. Align the arrow down the center of the bowstring with
the tip of the arrow point correctly positioned as
indicated in Fig. 7, page 3.

2. Initially position the sight pin over the centerline of the
arrow.

3. When using a release aid the arrow normally bends
more vertically than horizontally, so good clearance is
essential. Usually, the entire arrow contacts the rest
when it is shot and the fletching must be positioned to
clear the rest.
“SHOOT-THROUGH” RESTS - It may be necessary to
adjust the width of the arrow rest support arm(s) so the
fletching will pass cleanly over or through.
“SHOOT-AROUND” RESTS - Vane-to-nock indexing is
very important and should be adjusted to achieve
maximum clearance.

The Paper Tuning Arrow Test is the most commonly used
bow tuning test for archers using compound bows with
release aids. This test also works well for a finger release:

1. Firmly attach a sheet of paper to a picture frame type
rack approximately 24" X 24" (60 x 60 cm).

2. Position the center of the paper about shoulder height
with a target mat about 6 feet behind the paper to stop
the arrows.

3. Stand approximately 4 to 6 feet (1.2-1.8 m) from the
paper.

4. Shoot a fletched arrow through the center of the paper
with the arrow at shoulder height (parallel to the floor).

5. Observe how the paper is torn.

This tear indicates good arrow flight. The
point and fletching enter the same hole.

This tear indicates a low nocking point.
To correct, raise the nocking point 1/16"
(1.6 mm) at a time and repeat the proce­dure until the low vertical tear is elimi­nated.

This tear indicates a high nocking point,
clearance problem, or a very weak arrow
if you are using a release aid. To correct,
lower the nocking point 1/16" (1.6 mm) at
a time until the high tear is eliminated. If

the problem is unchanged after moving
the nocking point a few times, the disturbance is most
likely caused by a lack of clearance or by an arrow that is
too weak (if using a release aid). To identify a clearance
problem, check to see if the arrow fletching is hitting the
arrow rest. (See “Clearance Problems,” page 6.)

CR - If no clearance problem exists and you are using a
mechanical release, try:

1. A more flexible arrow rest blade if using a launcher

type rest or reduce downward spring tension on adjust­able tension launcher rests.

2. Decreasing peak bow weight if there is an indication

the arrow spine is too weak.

3. Reducing the amount the shaft overhangs the contact

point on the arrow rest.

4. Choosing a stiffer arrow shaft.

This tear indicates a stiff arrow reaction for

right-handed archers using finger release

(RF, CF). Left-handed finger release

archers will have an opposite pattern. This

is an uncommon tear for right-handed

compound archers using a mechanical

release (CR). However, it can occur and
generally indicates that the arrow rest position is too far to
the right or that there is possible vane contact on the inside
of the launcher rest.

Finger Release (RF, CF)-–To correct:

1. Increase bow weight/peak bow weight.

2. Use a heavier arrow point and/or insert combi-

nation.

3. Use a lighter bowstring (less strands or lighter material,

like Fast Flight®).

4. Use a weaker spine arrow.

5. Decrease cushion plunger tension or use a weaker

spring on “shoot around” rests.

6. CF only - Move the arrow rest slightly in toward the

bow.

Mechanical Release Aid (CR)–To
correct:

1. Move the arrow rest to the left. Continue
moving the rest to the left in small increments
until the right tear is eliminated.

2. Make sure the arrow has adequate clearance past the

cable guard and cables.

3. Make sure the bow hand is relaxed, to eliminate

excessive bow hand torque.

8 Arrow Tuning and Maintenance Guide

This tear indicates a weak arrow reaction
or clearance problem for right-handed
finger release (RF, CF) archers. Left-handed
finger release archers will have the opposite

pattern. For right-handed compound
archers using mechanical releases (CR), the left tear is
common and usually indicates a weak arrow reaction
and/or clearance problem. If a high-left tear exists, (see
next tear illustration) make sure you correct the nocking
point first before proceeding further.

Finger Release (RF, CF)–To correct:

1. Check for Clearance (See page 5).

2. Decrease bow weight/peak bow weight.

3. Use a lighter arrow point and/or insert combination.

4. Use a heavier bowstring (more strands or heavier

material).

5. Use a stiffer spine arrow.

6. Increase cushion plunger tension or use a stiffer spring

on “shoot around” rests.

7. CF only - Move the arrow rest slightly out, away from

the bow.

Mechanical Release Aid (CR)–To
correct:

1. Move the arrow rest to the right. Continue to
move the rest to the right in small increments
until the left tear is eliminated.

2. Make sure the bow hand is relaxed to eliminate exces-

sive bow hand torque.

3. Decrease peak bow weight.

4. Choose a stiffer spine arrow.

This tear shows a combination of more
than one flight disturbance. Use the
procedures that apply to the tear pattern
for your style of shooting, and combine the
recommendations, correcting the vertical
pattern (nocking point) first, then the

horizontal. If you experience a tuning
problem (especially with the nocking point location) and
are unable to correct a high/low tear in the paper, have
your local pro shop check the “timing” (roll-over) of your
eccentric wheels or cams.

For archers using release aids, it may, in some cases, be
necessary to apply adjustments opposite from those
described. The type of arrow rest and release aid
combination used can alter the dynamic flex of the arrow
to produce tear patterns contrary to those indicated
(although it is uncommon).

Once you have achieved a good tune at 4 to 6 feet (1.2-1.8
m), move back 6 feet (1.8 m) more and continue to shoot
through the paper. This ensures that the tune is correct and
that the arrow was not just in a recovery position when it
passed through the paper at the first distance.

SHORT DISTANCE TUNING

(

Recurve and compound - RF, CF, CR)

Many times it is not possible to shoot long distances when
your equipment needs to be tuned. The following method
results in a very good equipment tune at short distances.
Use this tuning method after you have completed one of
the basic bow-tuning methods—either the Bare Shaft Planing
or Paper Tuning Arrow Test.

Start at approximately 12 to 15 yards (meters) from the
target. Use a 40 cm or 60 cm target face and place it with
the face side in so you are shooting at a plain white target.

Up-Down Impact

Using fletched arrows only, shoot approximately 6 to 8
arrows along the top edge of the target face. This step
determines if your nocking point is correct. See Fig. 13.

Normally, small tuning problems show up at close range,
because the arrow has its maximum oscillation at short
distance. This test assists you in identifying these arrow
flight problems and makes it possible to make finer
adjustments than with the previous tuning procedures.

If you are unable to consistently hit the top edge of the
target face, there is probably a small tuning disturbance in
the equipment. To correct, make a 1/32" (.8 mm) nocking
point adjustment either up or down and shoot again.
Continue making nocking point adjustments in 1/32" (.8 mm)
increments (no more than 1/32" (.8 mm) at a time).

If your arrows are hitting the top edge of the paper more
consistently and you are achieving a straight, horizontal
line of arrows across the top of the paper, you are correcting
the disturbance. If the horizontal line of arrow impact is
widening, go back to your original nocking point position
and start making 1/32" (.8 mm) nocking point adjustments
in the opposite direction. This will provide you with the
correct nocking point position.

Left-Right Impact

Once you have achieved the straightest horizontal line of
arrows that your ability will allow, you are ready to tune for
left/right arrow impact. Shoot 6 to 8 arrows at the left edge
of the paper in a vertical line. See Fig. 14.

To improve the left/right impact for CR and CF
archers, move the in/out position of your arrow rest.
This is done to compensate for the effect of the
eccentric wheel. The offset of the eccentric wheel on

compound bows does not always compensate for
the degree of natural torque generated in the bow. The
wheel often torques or leans over slightly as it reaches the
full draw position. This is common and is nothing to be
concerned about. At full draw, the “limb center” you
started with in the preliminary setup may not really be the
true balanced center. Therefore, through some trial and
error, you must locate the best in/out position for the
arrow to obtain maximum accuracy.

Make a 1/32" (.8 mm) adjustment either in or out and shoot
again. Continue making 1/32" (.8 mm) adjustments until

Short Distance Tuning—Trouble Shooting

Fig. 13

Up-Down Impact

Fig. 14

Left-Right Impact

you achieve the best possible vertical impact line of
arrows. If the vertical line widens, go back to your original
arrow rest position and move it 1/32" (.8 mm) in the
opposite direction. If the vertical line narrows, continue

1

/32" (.8 mm) adjustments in that direction until you achieve

the straightest line possible.

CF archers using cushion plungers should make the
necessary arrow rest adjustments and then try a
second tuning adjustment using the cushion plunger's
spring tension. Increase or decrease spring tension

1

/8-turn at a time. Again, if the vertical line becomes
wider, return to the original spring tension setting and
make 1/8-turn adjustments in the opposite direction until
you achieve a narrow vertical impact line.

RF archers should make cushion plunger spring
tension adjustments only, increasing or decreasing
the spring tension 1/8-turn at a time. If the vertical line

becomes wider, return to the original spring tension
setting and make 1/8-turn adjustments in the opposite
direction until you achieve a narrow vertical impact line.
Do not move the in/out position of your arrow. The position of
your arrow to the centerline of the bow has already been
established in the preliminary equipment setup.

9

causes poor arrow grouping. What follows here is informa­tion that will help you perform the fine tuning adjustments
necessary to eliminate most or all of the minute tuning
problems.

Many archers have experienced one or all of the following
arrow grouping/arrow flight combinations:

◆ Poor arrow flight and good grouping - This is com­monly the result of a stiff arrow. The arrow yaws
slightly as it leaves the bow, but usually recovers
quickly and often produces very acceptable grouping.

◆ Good arrow flight and poor grouping - Although this
seems contradictory, the phenomenon is somewhat
common and relates to the tuning method you use.
Having a perfect bullet hole through paper using the
Paper Tuning Arrow Test, or having the bare shafts
impact exactly with the fletched shafts using the Bare
Shaft Planing Test, does not always mean your arrows
will group well; it only indicates you have good arrow
flight. For this reason, Easton has developed the Fine
Tuning and Micro Tuning methods, to assist you in
obtaining optimal grouping from your equipment.

◆ Poor arrow flight and poor grouping - This is most often
a problem of mismatched arrow spine or untuned
equipment. The information and tuning procedures in
this bulletin should help you correct this problem.

◆ Good arrow flight and good grouping - This should be
the end result of your efforts!

Arrow grouping patterns often reveal probable arrow
flight problems. Two of the most common grouping
indicators for determining arrow flight problems are
described below. The examples provided are shown in
FITA distances, although they easily correlate to any long­and short-distance shooting. Fig. 15 illustrates good
grouping patterns at the distances indicated.

Excessive Drag

The grouping examples in Fig. 16 show a large pattern at
long distances (90 m) but the grouping is within acceptable
limits at closer distances. This pattern implies the arrow
has too much drag. Excessive drag will cause the arrow to
become unstable due to the rapid decay of its forward
velocity. When forward velocity drops too quickly, insta­bility occurs. This unstable flight causes poor grouping at
long distances and extreme vulnerability to wind drift. On
lightweight arrows, it is very important to reduce drag to
a minimum to maintain maximum downrange velocity.
This can be done by reducing the size (height and/or
length) of the fletching or by reducing the angle of the
fletching, or both.

TROUBLE-SHOOTING
ARROW GROUPS

You may have heard people say, “If your arrows group
well at 20 yards, they will group at any distance,” or, “If
your arrows group at long distances, they will group at
short distances.” In some cases, neither statement is true.
There may be a minute disturbance in the equipment that
affects the equipment's potential for superior accuracy and

Insufficient Clearance

The grouping patterns in Fig. 17 show acceptable group­ing at the two long distances. However, the shorter dis­tance groups are not reduced in size proportionately to the
longer distance groups. (Compare to Fig. 15 on page 10).
This usually indicates a clearance problem or micro distur­bance within the bow and arrow system. To correct, see
the section on Clearance on page 5 or the Fine Tuning and
Micro Tuning sections on pages 12-14.

10 Arrow Tuning and Maintenance Guide

Fig. 18 illustrates why you may have problems with close­distance grouping while long-distance groups are good.

Fig. 15

Good grouping patterns show
progressively increasing grouping sizes
as shooting distances increase.

30 m 50 m 70 m 90 m

When an arrow is shot, it is at its maximum bending as it
leaves the bow. As the arrow travels farther, the amount of
flexing reduces (dampens). If the flexing reduces, then so
does the magnitude of any original disturbance. The
example shows that the arrow has some disturbance and
close range grouping is poor, although the arrow stabilizes
at longer range and provides acceptable groups. Micro
disturbances and clearance problems usually cause these
disturbances.

Fig. 19 shows the path of the arrow when it leaves the bow
without any disturbance. This is the path you are trying to
achieve in the Fine Tuning and Micro Tuning processes.

Fig. 16

Excessive Drag

30 m 50 m 70 m 90 m

Fig. 17

Insufficient Clearance

30 m 50 m 70 m 90 m

Fig. 18

Poor close range
grouping Acceptable
long range grouping

Fig. 19

Path without
disturbance

ADJUSTING THE BOW
AND ARROW SYSTEM

If you are having problems tuning your bow, you will need
to make some modifications to your equipment to achieve
a better tune. Here are some suggestions:

Bow Weight Adjustment

Virtually all compound bows, as well as some recurve
bows, have an adjustable draw weight. If your arrow
reaction is too stiff, increase the draw weight. If your arrow
reaction is too weak, decrease the draw weight.

Bowstring

Bowstring “weight” can have a significant effect on arrow
spine. Increasing or decreasing the number of strands in
the bowstring can influence the arrow's dynamic spine
enough to require a shaft size change of one full size
weaker or stiffer. If your arrow reaction is too stiff, de­crease the number of strands in your bowstring. If your
arrow reaction is too weak, increase the number of strands.
Serving weight (center serving) can also produce the same
effect. For example, monofilament center serving will
cause the arrow to react stiffer than lighter weight nylon
center serving. Simply changing from a metal nocking
point to a “tie-on” nocking point can have a noticeable
effect on arrow spine, due to the weight difference be­tween the two styles of nocking points.

90 m
80 m
70 m
60 m
50 m
40 m
30 m
20 m
10 m
0 m

Point and Insert Weight

Easton and Beman arrows can be tuned by using various
point and/or insert/outsert weight combinations. If your
arrow is too weak, go to a lighter insert or point. If your
arrow is too stiff, try a heavier insert or point. Continue to
change insert and/or point weights within the acceptable
balance point range (7-16% F.O.C.).

Brace Height

For recurve bows, another way of altering arrow spine is
with the brace height. By increasing or decreasing the
distance from the bowstring to the pivot point of the grip,
the dynamic spine of the arrow can be made slightly
weaker or stiffer. Increasing brace height will make the
arrow shoot weaker, and decreasing brace height will
make the arrow shoot stiffer.