Compound Bow Selection Guide
Introduction
Like many products, compound bows come in a variety of shapes, sizes,
colors, and levels of sophistication. If you’re new to the sport of
archery, we’ll guide you through all the jargon and technical hoopla and
help you to make a better-informed choice on your new bow.
If you're not already familiar with the components of the compound bows,
please take a moment to examine the illustration at right. Note
the red lines denoting brace height and axle to axle length, as these
attributes are mentioned frequently in this guide.
There are many pages of information here, you may wish to print this
section for your reference (16-20 pages).
Help Article Index:
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 Keeping
Things in Perspective
Undoubtedly, the modern compound bow is a fantastic hunting weapon. But
let's try to keep things in some reasonable perspective. Before you're
swayed by an advertising campaign promising exclusive-technology and
predatory bliss, try to keep in mind that the compound bow is still a
relatively simple device. The compound bow is constructed from readily
available materials, it has only a handful of moving parts, and it isn't
yet micro-processor controlled. So there's only so much technology which
can realistically be applicable to the design and production of a
compound bow. However, most bows are specifically marketed as a
"high-technology" product. Why? Because bow companies know what
modern bowhunters want the most - an edge - particularly a "technological
edge". Bowhunting has a historically low success rate, so it is no
surprise that compound bow advertising campaigns focus on offering
bowhunters a "technological" advantage - even if it's a little stretch
of the truth. They also know that outdoor product consumers love big
scientific words and impressive acronyms. So beware. Your new compound
bow could be packaged with a few Ultra-Lite Hyperpolyresin fibers of CBT
(cock-n-bull technology). |
The Brand Name Cult
 The
archery industry is often plagued by a "better than your bow" mentality
- as brand loyalty seems to often get out of hand. Some bow
manufacturers even seem to develop a cult-like following of shooters -
who'll openly malign any other brand of bows (just visit an online
archery forum). This is unfortunate for beginning archers who could
receive one-sided brand-x advice - which may or may not lead to a
good bow purchasing decision. So beware of any advice declaring one type
or brand of bow to be "the best". Imagine being told that a Subaru, for
example, is "the best" kind of car - and that every other brand was
totally inferior. Ridiculous right? The Subaru is certainly a fine
automobile, but it's not appropriate or practical for everyone. There
are many other high quality brands and models you could choose from. The
same is true for compound bows. The Point: There is no "best" brand or
"best" type of compound bow, so don't barricade yourself in too deeply
on any particular bow manufacturer's ranch. The bow that is best for you
is the bow that best fits your purpose, your size and strength, your
shooting style, your skill level, and your budget. |
 Statistical Deception in Advertising
If
the Nike shoe company paid the world’s 50 fastest sprinters to wear only
Nike brand shoes during competitions, it would be no surprise that most
of the big races would be won by athletes in Nike shoes. Would it be
fair then to conclude that Nike shoes make runners go faster? Of course
not! But the company could make it seem that way if they advertised the
race statistics without mentioning the paid endorsements. Sadly, some
archery manufacturers use this same little trick to entice buyers, and
it usually works. Beware of advertising campaigns that lead you to
believe their brand of bows are more accurate, and tempt you with
"stacked" statistics on how many tournaments their bows win. The Point:
Bows don’t win tournaments any more than shoes win races. The most
talented runners win races and the most talented shooters win archery
tournaments. Many factors are involved in accurate shooting (proper fit,
careful tuning, good technique, etc.). A good high-quality bow is just
one part of the equation. |
Understanding Trade Offs
There are many characteristics that archers look for in a new bow. Most
archers want a bow that has blazing fast performance, a silky smooth
draw stroke, very low hand-shock, a generous valley, and high let-off.
Most archers also want their bows to be very lightweight, compact,
quiet, forgiving to any flaws in technique, easy to tune, easy to
adjust, and affordable for any budget. Unfortunately, this perfect bow
doesn’t exist. To get a bow with a certain set of characteristics,
you’ll likely have to sacrifice some others. For example, very fast bows
are generally less forgiving, low recoil parallel-limb bows are
generally heavy, and so on. Ultimately you’ll have to decide which
characteristics are most important to you and choose the bow that best
fits your personal criteria. |
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POWER &
PERFORMANCE |
 Limiting Factors of Compound Bow Performance
Since speed is often the #1 consideration for new bow buyers, let's
begin with the issue power. First, we need to understand that bows
don't make energy. They just convert energy from one form to
another, so the chief performance-limiting factor is human power.
So what makes a bow more "powerful" is quite unlike
what makes a rifle more powerful. For a firearm, the "power"
comes from the cartridge, not from the shooter. So providing you can
withstand the recoil, you could shoot a gun for hours without ever
breaking a sweat.
With a compound bow it is just the opposite. Don’t be
fooled into thinking that a bow capable of shooting 335 fps is somehow
"more powerful" than one that shoots 290 fps, and that the effort
required to draw and shoot each bow will be the same. In general, if a
bow shoots faster it is because it requires more total effort to draw
the bow back. A compound bow is simply a machine that stores energy,
supplied by the shooter, then releases that energy into an arrow. And
sadly,
you can’t get more energy out of the bow than you put in. No amount of
high-tech engineering can change that. The Point: The compound bow gets
its energy from YOU. So if you
choose a bow that takes an eye-bulging amount of effort to draw back,
you may find that the bow isn’t very enjoyable to shoot in spite of the
gains in arrow velocity.
Learn more about theoretical limits of compound bow performance. |
 Energy
Storage and Release
When you pull the string of a compound bow, the limbs of the bow are
squeezed inward. The energy you supplied to draw the bow is stored in
the limbs, as potential energy, until you release the string. Upon
release, the potential energy is transferred into the arrow as kinetic
energy, as the limbs "spring" back into place returning the string to
it’s original position. Seems simple enough! But careful examination of
this process of storing and releasing energy is what gives a compound
bow its performance characteristics, and it is something you should
consider when selecting your new bow. The Point: In essence, there are
only two factors that determine how much "power" your bow will have: 1)
The amount of energy that can be stored in the limbs during the
drawstroke. 2) The amount of that potential energy that can be
successfully transferred into the arrow upon release (efficiency). |
 Understanding
the IBO Speed Phenomenon
Before we break down the issue of energy storage, we should be clear on
why it matters so much. Ultimately, manipulating and optimizing
energy storage is about generating faster arrow speeds. And
believe it or not, most archery enthusiasts are "speed junkies"
to some extent. When most shooters evaluate a new bow, one of their first questions is likely to be "How fast
does it shoot?". In the archery industry - speed sells. And like
the coveted 300 yard drive in golf, and the 300 mph funny-car
pass, the 300 fps mark seems to be the
benchmark for high performance in the archery market. As a matter
of consumer perception, a bow that shoots under 300 fps is
generally considered slow, while a bow that shoots over 300 fps
considered fast - in spite of the fact that there's no practical
difference in a 298 fps bow and a 302 fps bow. Nonetheless, manufacturers are under tremendous pressure to produce bows that pump
out big 300+ fps IBO speeds.
So what is an IBO Speed? Let's start at the top.
On the most basic level, there are three main components of actual arrow
speed: draw weight, draw length, and arrow mass. The higher the draw
weight - the faster the arrow will shoot. The longer the draw length -
the faster the arrow will shoot. And the lighter the arrow - the faster
it will go. So for the purposes of testing, a slick manufacturer could
setup a particular model bow and establish their bow's advertised speed
using an unrealistic 100# draw weight, 32" draw length, and shoot an
anorexic 250 grain arrow. Surely that combination would yield a blazing
fast test speed and would help to sell more bows, right? Well, not so
fast.
 To
really compare two bows, the industry uses an "Apples-to-Apples" method of
comparison. Manufacturers generally rate their bows using the same IBO
(International Bowhunting Organization) Standard. To get an accurate IBO
Speed rating, manufacturers must test their bows under the same preset
conditions: setting the bow for exactly 70# Peak Draw Weight, exactly
30" Draw Length, and they must shoot a test arrow that weighs precisely
350 grains. This levels the playing field on basic settings, so
the differences in IBO scores reflect other design attributes (brace
height, cam aggressive, bow efficiency, etc.). OK, fair enough!
However, since most manufacturers rate their own bows - they'll usually
give themselves a few added advantages by testing the bows with a bare
arrow shaft (no fletchings), a naked string (no nocking point, peep
sight, or silencers), the lowest possible let-off setting, and with a drop-away style rest. This helps to
maximize storage and eliminate friction so it's possible to squeeze out a few extra fps, but
it doesn't
necessarily reflect realistic shooting conditions. Manufacturers can
also squeeze a few more fps by shooting the bows from the hard-wall
(forcibly drawing the bow back a little too far) rather than from the
soft valley (more on wall and valley concepts later). And finally, the
manufacturer's IBO speed is likely to reflect their "best" test, rather
than their average test.
 Since the industry has no independent testing authority to actually
scientifically verify each of the manufacturers' claims, most bows end
up with advertised IBO speeds that are optimistically high, and nearly
impossible to duplicate. After all, most consumers don't have the
benefit of a chronograph, and few people actually shoot 70# DW, 30" DL,
and exactly a 350 gr arrow. And even if they did, there will always be
some percentage of variance among scales and chronographs to help
dismiss any claims of discrepancies. So there's really no way to hold
manufacturers accountable for their exact IBO speed numbers. From our
experience, they're all guilty of a little IBO speed padding. But in all
fairness, most are careful not to get too carried away. A little padding
and outright fabricating are different things.
As such, we recommend you consider the manufacturers' ratings as a
high-estimate. In most cases, the IBO speed is still a reliable
method of "Apples-to-Apples" comparison among different bow models. We
just have to accept that manufacturers invariably doctor-up their apples
to be a little sweeter than they actually are. It's just part of the
game. So don't assume something is "wrong" with your new bow just
because it doesn't shoot as fast as it's posted IBO Speed. Very
few, if any at all, bows do.
In fact, we periodically IBO test new bows here at our facility. Over
the course of several years and countless dozens of tests, we have NEVER
found a single bow which will actually shoot at or above it's advertised
IBO speed - from any manufacturer. Admittedly, some manufacturers come
closer than others, but in the real world, most compound bows will
actually shoot 10-20 fps less than their advertised IBO speeds. And once
setup in a typical hunting rig with a loaded-string, most will shoot a measurable 30-50 fps
less than the advertised IBO speed.
So while we understand that speed is a big selling point for compound
bows and a major performance characteristic that merits concern, we
strongly suggest you not get too caught-up in splitting hairs over IBO
speed. Compared to the wheel bows we grew-up on, any modern compound bow
is blazing fast. In the field, the 298 fps "Slow-Bow" will probably
perform just as well as the 302 fps "Fast-Bow". Neither you or the deer
will likely ever know the difference. |
 Force-Draw
Curve
So how is one bow capable of a 330 fps IBO Speed, while another only
shoots 290 or 300 fps? Again, it's all about energy storage.
As noted above, the key ingredients to arrow speed are draw weight, draw
length, and arrow mass. But there's more.
The amount of energy a bow stores also depends upon the
aggression (geometry) of the cam or
wheel design, the bow's let-off percentage, and the bow's brace height. To
better understand how each plays its role, you should familiarize
yourself with the Force-Draw Curve. The Force-Draw Curve is simply a
graph that shows how much energy is being stored in the limbs,
inch-by-inch, until the bow reaches full draw. Draw weight (in pounds)
is plotted against draw length (in inches). The green line represents
the amount of pressure the shooter must supply as the bow is drawn back.
Notice that draw weight varies throughout the drawstroke (an important
point for later in our discussion). When finished, the graph shows the
amount of energy stored during the drawstroke, and the shape of the
graph also gives us a good preview of the bow’s performance
characteristics and how smooth or radical the bow will feel to shoot.
Take a look at the following example graph and familiarize yourself with
it.
Area Under the Curve (no calculus required)
The Force Draw Curve (above) represents an average modern single-cam
compound bow. The amount of energy the bow stores is represented by the
darkened gray area under the curve. The more gray area you have, the
faster the bow will shoot. So how do we get more gray area? Just change
the shape of the curve. Of course, changing the shape of the curve
requires changing the bow's major characteristics. This is where draw
length, draw weight, cam design, let-off, brace height, and other
attributes come into play.
The Bow’s Drawstroke
The curved line on the force draw curve represents the bow’s drawstroke,
commonly known as the powerstroke. The powerstroke represents your
effort. The powerstroke begins as you pull the string back from the
resting position and is completed when the bow reaches full draw. Each
bow will have a different powerstroke depending upon its settings and
cam characteristics. Powerstrokes which are longer, higher, or wider
will result in increased energy storage and arrow velocity. |
 Theoretical
Limits
If speed were the only goal, a Force Draw Curve shaped like this one would yield the greatest possible amount of stored energy for any
bow at 70# max draw weight and 30" draw length. Of course, a bow like
this would be nearly impossible to aim and shoot. With a 0" brace
height, the string would rest on the bow's handle, and would nearly chop
off your hand with every shot. And the bow would have no let-off,
leaving you to hold back the entire 70# until release. A bow like this
would be far more dangerous to the archer than it would be to the game
animals. And although this graph is only a theoretical example, it can
help us to understand how today's super-cam bows are yielding faster
arrow speeds than ever before. But beware! The closer a bow's Force Draw
Curve comes to the theoretical limit graph, the more difficult it is to
draw, shoot, and control. |
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Draw Weight - Height of the
Powerstroke
The primary method for increasing the amount of stored energy during the
powerstroke is to shoot a bow with a higher maximum draw weight. All
other things being equal, a 70# bow will store more energy and shoot
faster than a 60# bow. However, this is a complicated issue you should
consider carefully when selecting your new compound bow. The maximum
draw weight of the bow is typically determined by the stiffness of the
bow’s limbs. Compound bows come in a variety of maximum draw weights,
but the most common are the 50-60# and 60-70# versions. Although you may
purchase a bow with 70# limbs, you can generally adjust the draw weight
1-10# down from the maximum weight. So a 70# bow could
actually be adjusted for 61#, 64#, 67#, or any draw weight within the
allowable range. However, it should be noted that a 70# bow, turned down
to 60#, will not perform as well as the same bow in a 60# version
operating at it’s maximum draw weight. Bows are generally more efficient
at or near their maximum draw weight.
Recommended Draw Weight Ranges
(Modern Compound Bows)
Here are some general guidelines for
choosing an appropriate draw weight. Of
course, each individual is different.
You should apply your common sense here
and interpret this chart with due
respect to your own age, general
physical condition, and Body Mass Index
(BMI). If you are new to the
sport, please read
additional discussion article on
choosing an appropriate draw length and
weight.
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Very Small Child (55-70 lbs.) |
10-15 lbs. |
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Small Child (70-100 lbs.) |
15-25 lbs. |
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Larger Child (100-130 lbs.) |
25-35 lbs. |
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Small Frame Women (100-130 lbs.) |
25-35 lbs. |
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Medium Frame Women (130-160 lbs) |
30-40 lbs. |
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Athletic Older Child (Boys
130-150 lbs.) |
40-50 lbs. |
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Small Frame Men (120-150 lbs.) |
45-55 lbs. |
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Large Frame Women (160+ lbs.) |
45-55 lbs. |
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Medium Frame Men (150-180 lbs.) |
55-65 lbs. |
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Large Frame Men (180+ lbs.) |
65-75 lbs. |
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Draw Weight - Effect on Arrow
Velocity
High poundage bows
require heavier, stiffer arrow shafts. So while they will
certainly generate more energy at the target, they may not necessarily
generate much faster arrow speeds at IBO standards. Lower poundage bows
can use lighter, more limber arrow shafts. IBO standards allow 5 grains
of arrow weight per pound of draw weight. So a 70# bow can shoot an
arrow (safely) as light as 350 grains. A bow set for 60#, no less
than 300 grains and so on. So surprisingly, when set for IBO
minimum standards, many bows are only fractionally faster in the 70#
version vs. the 60# version. Since a 70# bow must shoot the
heavier arrow, the savings in arrow weight offsets the loss of energy
storage during the powerstroke. So properly set-up for best speed, a 60# version
of most bows will perform within 10 fps of the heavier 70# version.
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Draw Weight - How Much is Necessary
Some states require a compound bow to meet certain draw weight minimums
in order to hunt large game like Whitetail Deer. Always observe the
rules and regulations for legally harvesting game in your state.
However, it should be noted that some of these rules have been in effect
for many years, and do not necessarily consider the recent technological
advances in archery manufacturing. The average bow of 15 years ago was
struggling to shoot 230 fps, and even at those speeds many bowhunters
got clean pass-thru’s on large game like Whitetail Deer. Today the
average bow is shooting over 300 fps at 70# draw weight and 30" draw
length. This means that even bows in shorter draw lengths and lower draw
weights will still provide plenty of velocity to penetrate the ribcage
of a Whitetail Deer and other large game. A modern single cam bow with a 50# peak draw weight
and just a 26" draw length will still zip arrows well over 220 fps. Of
course, if you plan to hunt larger game like Elk or Moose, or if you
plan to take shots from longer distances, you will need additional
kinetic energy for complete penetration and best chance of a
humane harvest. As a general rule, a 40-50# draw weight will provide
sufficient energy to harvest deer and a 50-60# bow will provide
sufficient energy to harvest larger elk-size species. Unless you're
planning to hunt huge animals like Cape Buffalo or Musk Ox, a 70+ pound bow really
isn't necessary. You can often be just as effective with a more moderate draw
weight. |
 Draw
Length Basics
Unlike a traditional recurve bow that can be drawn back to virtually any
length, a compound bow will draw back only a specific distance before it
stops (the wall). Compound bows are designed to be shot from the
full-draw position. If a compound bow is set for a 29" draw length, it
should always be shot from the full 29" draw position. But the bow
cannot be over-drawn, say to 30" or 31", without modifying the setup on
the bow. So the draw length on your compound bow must be set to match
your particular size.
Fortunately, most compound bows use a series of interchangeable or
"sliding" cam modules, which allows the bow to be adjusted to fit a
given range of draw lengths. If you don't know
your draw
length, you should determine that before shopping for a new bow.
Most men's bows adjust within a typical 26-30" draw length range, which
fits shooters from roughly 5'5" to 6'3". But that's not true for
every bow. Some bows have a narrow range of adjustment, or in some
cases, no adjustment at all. So step #1 in selecting your new bow
is finding a model will adjust to suit your particular draw
length. Of course, if you have an unusually short or long draw
length, your choices may be limited. So you'll need to take
particular notice of the bow's advertised draw length range.
Draw Length Affects Power
The longer your draw length, the longer
your bow's powerstroke will be - and the faster your bow will shoot. As
a general rule, 1" of draw length is worth about 10 fps of arrow
velocity. So
if your particular bow has an IBO speed of 300 fps, and you intend to
shoot the bow at 27" draw length - you should expect an approximate 30
fps loss in speed right off the top. But this is one area where
speed should be a secondary concern.
 If you're 5'9", it would seem ridiculous to buy a #13 shoe for your #10
foot. Similarly, it's not such a good idea to buy a 30" draw length bow, when
a 27" or 28" draw length would fit you much better. Shooting a
excessively long draw length will indeed earn you more speed, but to get
the extra speed you're likely to give-up a considerable amount of
control and comfort. It's a bad trade-off. As such, we strongly
recommend you NOT shoot a draw length that's too long for your
particular body size. Accuracy should never be sacrificed for a little
more speed. After all, a fast miss is no more impressive than a slow
miss.
Nonetheless, the majority of compound bow owners set their bows for too much draw
length, which results in poor shooting form - inaccuracy - and painful
string slap on the forearm. You will better enjoy and be more
successful with your new bow when it is fitted properly to your body.
And REMEMBER! If in doubt, choose a little LESS draw length rather than
a little more. If you are still unsure, or plan to shoot with a string
loop, you may benefit from reading our
Additional Discussion on Draw
Length. |
Cam Aggression
Of course, choosing a good bow isn't just about finding one that fits.
You'll also want to choose a bow that offers the right blend of
performance and shootability. This is where cam design comes into
play. Modern cams come in a variety of feels and levels of
aggression.
Some cams are specifically engineered to produce a smooth feel. Others
are made for best possible performance. The actual geometry of the cam
system determines how soft or aggressive the powerstroke will be. Take a
look at the additional sample graphs below, taken from bows with
different types of popular cam systems. |
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- ROUND WHEEL/LESS AGGRESSIVE: As you can
see, a Round Wheel style bow has a very smooth bell-shaped curve
which rises to peak weight for only a moment then gradually descends
to full let-off. This cam style will feel very smooth and easy to
draw, but will store the least amount of energy and shoot the
slowest. Although this type of cam has been around for decades, some
shooters still prefer the soft feel of this style cam - particularly
instinctive-shooters and finger-shooters. So a number of
manufacturers still offer bows with traditional round wheels or cam
geometry ground to replicate the round wheel powercurve.
- MEDIUM CAM/MODERATELY
AGGRESSIVE: The Medium Cam
graph is typical of today's basic single and hybrid cams. These cams
are more aggressive, ramping to peak weight more quickly and then
coming to full let-off more abruptly. So they tend to store up more
energy than a Round Wheel bow, and shoot notably faster. However, a
Medium Cam is sure to "feel" a little heavier than a Round Wheel bow
of equal peak weight. This type of cam geometry suits most shooters
well, offering a reasonable blend of feel and performance.
Medium cam bows will usually have moderate IBO speeds in the 295-310
range.
- HARD CAM/VERY AGGRESSIVE: The last example
is a Hard Cam system, optimized for maximum energy storage and
speed. Notice how quickly the bow ramps up to peak weight and how
quickly it transitions to let-off. Also notice the distinct
high-plateau on the graph where the shooter must draw the bow over
several inches at peak weight. This type of cam geometry will store
dramatically more energy, and will usually have an IBO Speed of 320
fps or more. The downside is that Hard Cams feel harsh and heavy
compared to other bows of equal peak weight. So they certainly
aren't for everyone. But for shooters who want the hottest possible
arrow speeds, the Hard Cam is the way to go.
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The Valley
The "V" shape formed between the two halves of the graph is commonly
referred to as the "valley", which represents how quickly the bow
transitions to and from full let-off. A bow with a narrow valley
is quick to "jerk forward" if you relax too much at full draw. On
the other hand, a wide valley bow allows a
little more leeway for shooters who tend to creep (a common
shooting-form flaw). Aggressive hard-cams tend to have the most narrow
valleys since delaying the let-off allows additional energy can be
stored during the powerstroke. But be advised, managing a narrow
valley bow takes a little getting use to.
If you're accustom to an older soft cycle bow, an aggressive narrow
valley cycle may be a little nerve-racking at first. Very
aggressive cams can have valleys that are effectively less than 1/2"
wide at full draw. This can cause creepers to jerk and flail awkwardly
at full draw, since the holding weight abruptly changes if the bow isn't
held firmly against the stops. So to avoid being sucked thru your
Whisker Biscuit, be prepared to make some moderate changes in your
shooting form if you elect to go with an aggressive cam bow.
CAUTION: If you draw a high let-off
bow without an arrow on the string, make sure you have a firm grip. High
let-off bows are easily dry-fired. Once you draw the bow back and begin
to relax, you're likely to forget that the full 70 lbs is waiting for
you, just an inch or two away. When you begin to let the bow down, your
grip is too relaxed, and WHACK! DRY-FIRE! Dry firing a bow is not only
dangerous to the shooter, but it is an ideal way to seriously damage
your expensive compound bow and generally voids most manufacturer
warranties. |
Brace Height
Brace height is yet another important factor in the energy storage equation.
A bow's brace height is simply the distance from the string to the pivot
point of the bow's grip. You can kind-of think of brace height as
how close the string will be to your wrist when the bow is at rest. The closer the string is to your wrist, the more work you
have to do to get the bow drawn back. If you're drawing a 6" brace height bow back to a 30" AMO draw length, you'll have to pull the string back a total distance of
22.25" before you reach full draw*. But if the string rests farther
back from your wrist to start, say the bow's brace height is 8", then you'll only
have to pull the string back for 20.25". So the bow's brace height
also figures into how LONG the bow's powerstroke will be.
And as you know, a longer powerstroke generates more energy.
As a matter of energy storage, brace heights are analogous to the length of the rubber-band on a slingshot. If you
hold a slingshot at arms-length and pull it back to your cheek, a
shorter rubber-band would be stretched for a longer distance (and shoot faster) than
the same slingshot with a longer rubber-band. In much the same way, a
short brace height bow stores more energy and shoots faster than a tall
brace height bow (all other things being equal). So brace height has the same affect on
total powerstroke length as does the bow's draw length setting. The
only difference is that the brace height determines where you start and the
draw length determines where you stop. But unlike draw lengths, brace
heights aren't adjustable. So you have to get this one right the first
time. You can't change your bow's brace height later, should you
change your mind.
If you compare brace heights and IBO speeds, you'll find an obvious
correlation. Shorter brace heights tend to make for faster bows.
Easy enough. Then it would seem that in order to get better performance from a
compound bow, all you have to do is look for a model with a short brace
height, right? Well, not so fast! Short brace height bows may be
hot-performers, but
they will come with a few drawbacks you should think about
*A bow's AMO draw length is measured
1.75" beyond the grip pivot point. So a bow's powerstroke distance
is found by subtracting the brace height and 1.75" from the AMO draw
length. |
Brace Height - Speed vs. Forgiveness
If you’ve been shopping for a new compound bow, you’ve certainly noticed
a variety of advertised brace heights, generally ranging from 5-9".
But if shorter brace heights result in faster bows, then why aren’t all
bows designed with short brace heights? Trade-offs! That's
why. Short brace heights aren't automatically favored because a
bow's brace height has a profound effect on the bow’s forgiveness and
shootability. Short brace height bows are generally less forgiving
and require more skill to shoot accurately. Since the arrow is in
contact with the string for a longer distance and period, there is more
opportunity for any glitches in your shooting form (hand-torque, trigger
punching, etc.) to have a detrimental effect on the arrow’s flight.
Longer brace heights have the opposite effect, limiting the effects of
form glitches. In addition, very short (sub-6") brace height bows
tend to yield more string-slap on the shooter's forearm (ouch!).
So there are some trade-offs to consider here.
If you shoot with absolutely perfect form and technique, a short brace height bow will
be just as accurate as it’s longer brace height cousins. But if you have
average skills and are prone to occasional goof-ups, a bow with a little
longer brace height will yield better accuracy in most shooting
situations. The average new compound bow has a brace height of
approximately 7". Bows with shorter brace heights (5-6.5") will be
faster but less forgiving to shoot. Bows with longer brace heights
(7.5-9") will generally shoot slower but will be more forgiving to your
errors. Consider this carefully when choosing your new hunting or 3D
bow. Unless you have a specific need for a blazing fast bow, you may
find that a more moderate brace height will increase your enjoyment of
archery and your success in the field. SPECIAL NOTE: Tall guys with draw
lengths 30" and above should be especially conscious of brace height -
as a long draw length and a short brace height are a particularly bad
combination, especially for new shooters.
Brace Height Market Trends
 Just
as 300 fps seems to be the accepted IBO speed-minimum, 7 inches is the
generally accepted brace height minimum in today's compound bow market.
If you visit our
compound bow specification charts, you'll surely notice that a
disproportionate number of bows are advertised with exactly a 7" brace
height. This isn't by accident. Experienced shooters -
particularly bowhunters - tend to avoid short brace height bows,
regarding any brace height under 7 inches as "radical" or "unforgiving".
So a bow with a 6 7/8" brace height is often a lame duck - at least
regarding bow sales. As such, most manufacturers try to aim to hit
the market-pleasing 7+ inch brace heights on most of their new bow
designs. As a matter of selecting a new bow, we submit there's
probably no justification for such an exacting prejudice, as there's nothing particularly lucky about
a 7" brace height. But that does seem to be the commonly accepted line-in-the-sand between performance and shootability.
|
Short-Draw Archers - Built in Forgiveness
If you are a short-draw archer (27" draw length or less), you'll be
pleased to know you have a nice advantage regarding forgiveness and
shootability on your compound bow. As we noted earlier, a bow which has
a 6" brace height and is set for long 30" draw length will have 22.25"
powerstroke. This means the during the shot, the arrow will remain
in-contact with the string for approximately 23-24" (including string
follow-thru) until the arrow finally releases. This would generally make
for a rather unforgiving setup. But that same bow in the hands of the
short-draw archer will be considerably MORE forgiving to shoot. If
a short-draw archer shoots the same bow at - say - 26" draw length,
his/her powerstroke will only be 18.25" long. So the short-draw archer's
arrow gets off the string in a shorter distance - thus the short-draw
archer has some "built-in" benefits of forgiveness. If you are a
short-draw archer, don't spend too much time fretting over brace height.
Instead, consider shooting a bow that's a little more aggressive. The
same bow that might give your 6'4" hunting buddy fits, will be quite
manageable when set for your short draw length. And choosing a more
aggressive bow will help you to recover some of the speed and power lost
in a short-draw setup. |
Kinetic Energy: Arrow Mass
& Arrow Velocity
So how does energy storage and arrow speed translate into actual hunting
penetration? In the shooting sports, penetration is most often
expressed as a function of kinetic energy (KE). This topic is
covered in great detail in our
Arrow Selection Guide, but we'll mention the highlights here in the
bow guide as our final thought on bow "power".
In the end, the measurable "power" of your new bow - it's total kinetic
energy output - ultimately depends upon just two variables: the mass of
the arrow and the speed of the arrow. Kinetic energy of an arrow
can be found by using the formula KE=(mv²)/450,240 where m is the mass
of the arrow in grains and v is the velocity of the arrow in fps.
So if your new bow setup ultimately shoots a 400 grain arrow at a
respectable 250 fps (a typical field-output for a modern rig), your actual kinetic energy or "power" will be:
KE=(mv²)/450240
KE=[(400)(250²)]/450240
KE=25000000/450240
KE=55.53 ft-lbs |
So, will that be
enough? Take a look at Easton's Kinetic Energy Recommendation
Chart.
|
Kinetic Energy |
Hunting Usage |
|
<
25 ft. lbs. |
Small Game (rabbit, groundhog, etc.) |
|
25-41 ft. lbs. |
Medium Game (deer, antelope, etc.) |
|
42-65 ft. lbs. |
Large Game (elk, black bear, wild boar, etc.) |
|
>
65 ft. lbs. |
Toughest Game (cape buffalo, grizzly, musk ox,
etc.) |
|
According to Easton's recommendations,
55 ft-lbs of KE would be plenty for most popular North American game
species. But is that a guarantee of success? Absolutely not!
Remember, bowhunting is a traditional and difficult sport. And
regardless of how you crunch your numbers during pre-season, you can't
avoid the elements of chance during the actual hunt. Shooting a live
animal in the woods is quite different than shooting a block of
ballistics gel in a laboratory. In the field you'll encounter
unpredictable and complex variables that limit any mathematical model to
just a "best guess". If you consider that your arrow must arrive on
target then pass through layers of hair, hide, muscles, bones (perhaps),
and a host of other tissues.....AND that all of this is happening in an
uncontrolled outdoor environment, it's pretty clear that the issue of
hunting penetration cannot truly be distilled into a mathematical
puzzle.
As many experienced bowhunters can attest, just as it's possible to make
mistakes and get lucky, it's also possible to do everything right and
come-up empty handed. That's just part of the sport. However, with
good equipment, good technique, smart planning, and some common
sense, you can surely tip the scales in your favor and maximize your
chances of success in the field. |
|
CAM DESIGN CONSIDERATIONS |
Let-Off Basics
If you've ever shot a heavy recurve or longbow, you've certainly noticed
that you're holding back the maximum draw weight just when you come to full
draw, so you must aim and release the arrow quickly before you run out
of steam or begin to shake. The original compound bow was designed
to eliminate this problem, offering the shooter more time to aim and
release the arrow. In contrast with the traditional bow, the draw
weight of the compound bow decreases (sometimes dramatically) just as you come to full-draw. This is known as
LET-OFF, which is controlled by the geometry of the cam system.
Early compound bows featured a 35-50%
let-off, a welcome relief. But today it is common for bows to have
let-off in excess of 75%. A bow with a 70# draw weight and 80% let-off
will require the shooter to hold back only 14 lbs. once the bow reaches
full draw. Holding back such a small amount of weight, the shooter has
the luxury to take more time aiming and releasing the arrow. Of course,
some argue that you can have too much of a good thing. There is some concern that a bow
can have too much let-off, making the bow feel "sloppy" at full draw.
Maintaining some level of resistance at full draw is perhaps necessary to keep
things in good natural alignment. However, the average archer will find
the mid to high let-off bow to be more comfortable to shoot. Advanced
archers and back-tension shooters often prefer a little less let-off.
The only other disadvantage to a high (over 75%) let-off cam is a small
reduction in arrow velocity vs. a lower let-off cam system. All other
things being equal, a bow with 65% let-off will shoot faster than a bow
with 80% let-off. However, the difference in speed is usually only a few
fps. Fortunately, many cams use interchangeable modules which give you
the option to easily switch between different available let-offs. Some
cam systems even offer adjustable let-off right on the cam without the
need for additional modules. If you would like the option to
experiment with different let-offs, look for this feature on your new
bow.
While you're bow shopping, you may notice some bows are advertised with
2 different let-off percentages. There's a bit of a technical
snafu here, so bear with us, this takes a little time to explain.
Depending upon how you compute the let-off percentage, you can get two
clearly different let-offs for the same bow, the "Effective" and
"Actual" let-off. While you're drawing the bow back, friction in the
bow's cables, cam bushings, cable slide, etc. adds a little draw weight
to the cycle. Unfortunately, the extra energy you used to overcome that
friction gets lost when you let the bow back down (or fire the bow). So
basically, the bow doesn't put-out as much energy as you put-in. Some of
the energy is stolen by friction (hysterisis). Bummer!
Actual vs. Effective Let-Off Computation
Due to hysteresis, it would take more energy to draw the bow all the way back than it
would to hold it while slowly letting it back down from full draw. It's
kind of an abstract concept, so imagine if we put a bow in a vice and
then drew it back using a rope and winch. Now imagine we also had a
spring scale hooked to our winch, so we would know exactly how much
pressure was on the rope at all times. If we started drawing back the
bow by cranking the winch, and watched the reading on the scale the
whole time, the weight would go up and up until the bow reached it's
peak weight about 1/2 of the way back. If we kept cranking on back to
full draw, the weight would drop-off as we arrived at the draw cycle's
point of let-off (full draw). NOW! If we reverse our winch and slowly
let the bow back down, we should expect the scale to read the same, just
with the cycle in reverse, right? Nope! As soon as we begin letting the
bow back down, all the readings will be slightly less than they were
when we drew the bow back. This degradation or loss of effective draw
weight due to friction forces is called hysterisis.
|
 |
SO....to compute our percent let-off,
all we need to know is the bow's peak weight and it's minimum weight at
full draw. In the example above (blue line), the bow's peak weight
is roughly 67# and the minimum weight is about 20#, which computes to a
70% actual let-off. But when you measure the peak and minimum
weight on the return stroke (red line), you'll get slightly different
numbers. The minimum holding weight is clearly less on the return
stroke (about 16#). So if you compute the 16# on the red line as a
percentage of the original 67# on the blue line, you get 76% let-off.
This is the bow's "effective" let-off.
Why the mathematical trickery? Simply put, high let-off bows are
better sellers. So it's pretty common for manufacturers to only
list their effective let-offs, and make little mention of actual
let-off. In fact, unless the manufacturer specifically notes the
word "actual" in their let-off specifications, assume the let-off
measurement is the effective variety. |
Let-Off Compliance for State Regulations
Be advised that a
few states disallow high let-off bows for big-game hunting. Oregon and
Idaho, for example, restrict let-off to a maximum of 65% (actual). So
if in doubt, please check your current state hunting publications to be
sure your your new equipment will be in compliance with your state's
regulations.
 Let-Off
for Pope & Young Club
One final consideration for choice of let-off.....the Pope and Young Club
is one of North America's leading bowhunting and conservation
organizations. Founded in 1961 as a nonprofit scientific organization,
the Club is patterned after the prestigious Boone and Crockett Club. The
Club advocates and encourages responsible bowhunting by promoting
quality, fair chase hunting, and sound conservation practices.
Bowhunters who harvest record animals may qualify to have their trophy
listed in this organization's record books. However, for a compound bow,
Pope & Young has traditionally allowed a maximum of 65% let-off
(actual) to
qualify for listing in their record book. But in response to increased
pressure by high let-off enthusiasts, the rule was changed in 2004.
Record animals taken with higher let-off bows will now be listed, but an
asterisk "*" will be placed beside the hunter's name, indicating the
animal was taken with a high let-off bow. |
Cam Type
Modern compound bows generally come with a choice of 4 different
types - or styles - of cam systems. While they all accomplish a
similar mechanical goal, they each have a unique set of attributes and
respective advantages and disadvantages.
| |
|
Single Cams
Often described as a Solocam or One Cam, the single cam
system features a round idler wheel on the top of the bow and an
elliptical shaped power-cam on the bottom. The single cam is
generally quieter and easier to maintain than traditional twin
cam systems, since there is no need for cam synchronization.
However, single cam systems generally do not offer straight and
level nock travel (though the technical debate continues), which
can make some single-cam bows troublesome to tune. Of course,
all single cams aren't created equal. There are good ones and
bad ones. Some are very fast and aggressive, others are quite
smooth and silky. Some offer easy adjustability and convenient
let-off choices, others don't. But most single cams do offer
reasonable accuracy and a good solid stop at full draw.
Overall, the smoothness and reliability of the single cam is
well respected. And the single cam is today's popular choice on
compound bows. |
| |
|
Hybrid Cams
The Hybrid Cam system has gained considerable popularity
over the last few years. The hybrid cam system features two
asymmetrically elliptical cams: a control cam on the top, and a
power cam on the bottom. The system is rigged with a single
split-harness, a control cable, and a main string. Though
originally invented and marketed by Darton Archery as the C/P/S
Cam System, Hoyt's introduction of the Cam & 1/2 (a variation of
the original C/P/S System) in 2003 has brought hybrid systems
into the limelight. Hybrid cams claim to offer the benefits of
straight and level nock travel, like a properly-tuned twin-cam
bow, but without the timing and synchronization issues. Indeed,
hybrid cams require less maintenance than traditional twin cams,
but it's probably a technical stretch to say that hybrid cams
are maintenance free. They too need to be oriented (timed)
properly for best overall efficiency and performance. There are
several hybrid cam models available which are impressively fast
and quiet, rivaling the best of the single cam bows. |
| |
|
Twin Cams
A twin cam system is sometimes described as a Two Cam or
a Dual Cam. The twin cam system features two perfectly
symmetrical round wheels or elliptical cams on each end of the
bow. When properly synchronized, twin cam systems offer
excellent nock travel, accuracy, and overall speed. However,
twin cams do require more maintenance and service to stay in top
shooting condition. But thanks to today's crop of advanced
no-creep string fibers, they are becoming increasingly easier to
maintain. Many hardcore competition shooters are quite loyal to
the twin cam concept. And it's probably worth noting that the
twin cam bow is dramatically more popular outside of the US and
Canada, where there is less advertising to hype the single and
hybrid systems. Aside from maintenance issues, the only
true disadvantage to twin cams is the tendency for increased
noise (compared to typical single and hybrid cams).
Nonetheless, the twin cam is still the cam system of choice for
many serious shooters. Twin cams are also very popular
choice for youth bows. |
| |
|
Binary Cams
Introduced by Bowtech Archery as a new concept for 2005,
the binary cam is a modified 3-groove twin-cam system that
slaves the top and bottom cams to each other, rather than to the
bow's limbs. Unlike single and hybrid systems, there is no
split-harness on a binary system - just two "cam-to-cam" control
cables. This creates a "free-floating" system which allows the
cams to automatically equalize any imbalances in the limb
deflections or string and control cable lengths. So
technically, this self-correcting cam system has no timing or
synchronization issues and should achieve perfectly straight and
level nock travel at all times. While this technology is still
developing, the binary cam concept is clearly turning heads in
the industry. Bowtech's binary cam models were among the
fastest (and most popular) bows on the market for 2005 and 2006,
and they've even attracted a number of copy-cats for 2007. Only
time will tell, but we strongly suspect that the binary cam will
continue to gain popularity and respect in the market. |
|
 Cam
Type Hype
Cam technology (and its licensing to other bow companies) is the
financial bread-n-butter for some bow manufacturers. So it's no
surprise that they focus much of their efforts on marketing and
promoting their particular cam style(s). As a result, this is one
area in particular where CBT often gets out of hand. For example,
if a cam is
designed to feature an unusually deep string groove, the consumer
won't see an ad that says "Now with deeper grooves in the cams".
You're more likely to see something like, "Now featuring the
CoreTrack™ XS4 Cam with Accugroove Technology". So don't be
too swayed by high-tech sounding cam advertisements. Manipulating
the geometry of a small piece of machined aluminum isn't exactly a clean-room technology.
Cam Parity
While the technical subtleties and respective merits of the various cam
systems could be debated in perpetuity, in the real world there is an
obvious performance parity among them all. This isn't to say that
they all perform exactly the same. But to say that one cam style
really offers a crucial field-advantage over another would be something
of a stretch. They all accomplish the same basic mechanical goals
and there are great-shooting bows available in all of the cam style
categories. As such, we recommend you not be too cam-monogamous
when doing your bow shopping. |
|
LIMB DESIGN |
 Solid
vs Split Limbs
This is a tough one. Solid limb proponents claim
that solid limbs offer better torsional stiffness and
more accurate than split limbs. Split limb proponents claim that
split limbs are more durable and produce less hand-shock than
solid limbs. While we don't see much evidence to
support these positions, it does seem clear that solid limbs are leading
the way - at least by popular vote. BTW, this wasn't always so.
Just 7 years ago, the market was rather evenly divided. Today,
only a handful of manufacturers use split limbs (Hoyt, Fred Bear,
Alpine, etc.). Surprisingly, some bow companies do both, and seem
willing to switch back and forth as situations warrant. For
example, Bowtech has always exclusively used solid limbs. However,
for 2007 they introduced 2 new bows utilizing split limbs to accommodate
a new riser design. So perhaps the choice of solid limbs vs. split
limbs isn't really such a critical black or white choice for
enthusiasts. Of course, you're bound to hear some marketing jabber
about how one limb outperforms another. But in the field, solid and split limb
bows perform similarly. Whatever your preference, limb type should be a
minor consideration compared to the other bow design characteristics
we've discussed. Weigh this bow attribute lightly. Beyond the aesthetic
appeal, it probably doesn't matter, as one type is likely to perform
about as well as the other. |
 Bow Recoil - AKA, Hand-Shock
Some call it kick, or hand-shock, or refer to it as
shot-vibration, but we're all usually referring to the same thing,
recoil. Of course, a bow's recoil is rather backwards from
that of a gun - pushing away instead of towards you. But the
phenomenon is basically the same - an undesirable jolt at the point of
the shot. Why does it happen? It's Sir Isaac Newton's fault
of course. When a bow is drawn, the limbs compress back under
tension. When the bow is fired, the unloading limbs jolt forward
and return to their original positions. Since the cams are
attached to the bow's riser, the inertia of the fast-moving limbs
(Limb Thrust) causes
the bow's riser to jump forward too. And since your
hand is attached to the riser at the bow's grip, you feel the riser's
abrupt movement as recoil. It's a natural byproduct of such an
explosive energy release, and on some bow designs it's quite noticeable
- perhaps even detrimental.
The Path to Recoil Abatement
Very little was said about bow recoil 20 years ago. Of course,
there wasn't much that could be done about it at the time, and most
enthusiasts went about their merry ways never knowing the difference.
But as cam technology improved, and the compound bow began
storing/releasing more and more energy, recoil became more of a
center-stage issue. By the late 90's, the average bow literally
leapt out of your hand at the shot. The industry's immediate response was to develop dampening
technologies. By the turn of the millennium, archery consumers
were spending millions on rubber stick-on's, jiggly
stabilizers, hydraulic whatchamacalits, and harmonic doo-dads in an
attempt to reduce bow recoil. The whole industry seemed almost
obsessed with it. Unfortunately, these aftermarket wonder products
did little, if anything, to counteract forward limb thrust. In all
fairness, they did make bows quieter, but they could not defeat the
inertia of the forward thrusting limbs.
Higher Limb Angles
 So
while the accessory manufacturers were busy making vibration analysis
graphs and marketing dubious claims of oscillatory abatement, the bow
manufacturers were digging into the root of the problem - limb thrust. The
obvious solution was to reorient the limbs such that they didn't thrust
forward upon release. But in order to do that, the limbs would
have to be oriented almost horizontally - parallel with each other -
such that they could load and unload vertically. That way the top
limb would thrust upward, the bottom limb downward, and the opposing
forces would cancel each other out. Of course, archery consumers
needed a little time to warm up to the concept. After all, a bow with
horizontally oriented limbs would hardly look like a bow at all.
So over the next 5 years, bow manufacturers began to present bows with
increasingly steep limb angles. And the steeper the limb angles
got, the less recoil the bows seemed to have. As expected, archery
consumers were skeptical at first. But by 2005, high limb angle parallel
style bows
were totally dominating the compound bow market.
Learn more about the parallel limb craze.
 Parallel-Limb
Bows are Born
Creating a parallel-limb bow has not been without some manufacturing
headaches Among the fundamental challenges, a parallel limb bow is
built using a riser that's twice as
long, and limbs that are half as long (that's an exaggeration - but you
get the point). As you might expect, this
precipitated a number of problems that took a while to solve. So
early parallel limb bows showed some ugly signs of the learning curve. But season by season,
the parallel limb designs got better and better. Today the market abounds with
smartly refined parallel limb models which are arguably some of the best
compound bows ever produced. And can you guess what they're all missing?
Exactly...RECOIL. Today's parallel limb bows generate little to no
forward limb thrust and offer the smoothest releases of any bows ever
produced.
Who's Your Daddy?
So who do we thank for birthing the parallel limb bow? As you
might expect, the various bow companies can't help but squabble about
who deserves the credit - each spinning their own versions of
how the technology was "created". But the fact is, the parallel
limb concept isn't really an invention in the traditional sense.
It's more of a fundamental change in thinking, like making a car more
aerodynamic so it gets better mileage. We submit that the trend to
parallel limb bows is more of an inevitable evolution in the bigger
scheme of compound bow manufacturing. But in all fairness, a handful of the
key manufacturers, like Bowtech & Mathews, were brave enough to stick
their necks-out first and prime the pump. |
Parallel Limb Popularity Soars
Parallel limb bows have undoubtedly become the hottest-selling bows on
the market. Even considering their once hefty price-tags, parallel
limb bows have managed to become the new standard. And today,
parallel limb bows are no longer just reserved for the $600+ elite
buyers. For 2007, every bow manufacturer from Alpine to Whisper
Creek has adopted the parallel limb designs and the prices are coming
back in-line. There are some really nice parallel limb bows on the
market for 2007 for as little as $299. So it seems that the
traditional D-shaped bows could be destined for the bargain-bin and
everyone can take advantage of the parallel limb innovation in 2007.
Parallel Neurosis
Unfortunately, the parallel limb craze has precipitated an almost
neurotic obsession with detecting and palm-analyzing recoil - so much
that buyers are practically ignoring other attributes. We see bow
shoppers every day who shoot a bow just one time, then make their
judgment based solely on how much recoil they feel. Some
enthusiasts are so focused on recoil, or enamored by the lack thereof,
they almost forget to consider the bow's grip comfort, balance, and
drawstroke feel. We suggest you not focus your attention beam so
tightly on just how recoil-free a bow can get. If the bow
has parallel limbs, the recoil is going to be low. So don't let
all other characteristics get demoted to tertiary concerns.
There's more to a good-shooting, good-feeling bow than just the absence
of recoil.
 Are
Parallel Limb Bows More Accurate?
Probably not. While the parallel limb bow is notably smoother and
quieter at the shot, there's no direct evidence to suggest a parallel
limb bow is inherently more or less accurate than a standard D-shaped
bow. In fact, target archery professionals still prefer the more
upright standard limb designs. Of course, we must also consider
that parallel limb bows tend to be short. Target shooters
generally prefer longer axle-to-axle designs. And since target
shooters aren't usually concerned about noise, or recoil for that
matter, the parallel limb bow isn't as much of a phenomenon on the
competition circuits. But for bowhunters, it's a different story.
Within a typical bowhunter's range, a parallel limb bow is likely to
provide the same consistency and accuracy as any other style bow.
 Do
All Bowhunters Love Parallel Limb Bows?
Certainly
not! Parallel limb bows don't appeal to everyone, as they have a
few drawbacks of their own. While the generation-x buyers tend to
love the radical batwing shape of parallel limb bows, we hear a number
of more traditional buyers comment that parallel limb bows are "ugly".
And perhaps it's a fair criticism. For those who appreciate the
sleek lines and traditional appearance of a bow, the parallel limb bow
is no beauty queen. But the criticisms aren't just about
appearance (although we're sure PLB's have nice personalities).
PLB's on the Chunky Side
As we mentioned earlier, parallel limb bows start with a very long
riser. Since most of the bow's weight is in the riser, the
parallel limb bow is typically 1/2 pound heavier than standard D-shaped
bows. In 2001, the average compound bow weighed just 3.6 lbs.
Today, that average is well over 4 lbs. You may in fact notice
that the term "lightweight" has largely disappeared from bow
advertising. The dilemma is balancing weight against structural
stability. The longer a riser is, the stronger it must be.
So there is only so much material the manufacturer can machine away
(cut-outs in the riser) to reduce the riser's finished mass. So
for now, parallel limb bow buyers will simply have to live with the
extra weight.
Total Bow Mass
Interestingly, adding some mass to the bow isn't automatically a bad
thing. Some shooters actually prefer a little more weight,
particularly competition shooters. A heavier bow tends to be more
stable at full draw and easier to hold steady while aiming. So in
that respect, PLB's aren't necessarily a step backwards. On the
other hand,
some shooters clearly prefer the lightest bow possible - particularly
hunters who hike long distances. Perhaps there is no right or
wrong here, as this is clearly a matter of personal preference.
But let's keep things in reasonable perspective. Less than 2 lbs.
separates the very lightest from the very heaviest bows on the market.
And among popular men's hunting bows, the difference from the lightest
to heaviest is about 12 ounces (the weight of a can of soda). So
even considering the extra mass of the PLB riser, your
fully-accessorized bowhunting rig will still tip the scales well under
the weight of your hunting rifle. Unless you have a specific need
for a very lightweight bow, you shouldn't spend too much time splitting
hairs over whether you should get a bow that weighs 3.9 lbs or 4.1 lbs,
as it is likely you'll never notice the difference. Other design
features should take much higher precedence in your selection of a new
compound bow.
|
|
AXLE-TO-AXLE LENGTH |
How Long or Short Should I Go?
First, as the name suggests, bows are measured for length from the
center of one cam axle (a round metal rod connecting the cam to the
bow's limb) to the other. Please note that a bow will actually
stand 3-5" taller than it's published axle-to-axle length. This is
because the cams extend well beyond the axles. So if you are
buying a new bow and need the bow to fit into a particular case, or
storage space, you should take this into account.
OK. So how long should a good bow be? Compound bows range in
length from well under 30" to over 45". But the average length is
about 35", dramatically shorter than the average bow of 15 years ago
which was a staggering 43" long. So the market trend is certainly
towards more compact designs, and what was once called a "short-axle"
bow is now hardly considered mid-length.
However, shooters take this attribute very seriously - as they should.
Bows can be sorted by axle-to-axle length into one of 3 broad
categories:
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 |
(Under 32") Short Axle Bow
Short axle bows are very popular with Eastern treestand
hunters and those who want a compact, lightweight, and
maneuverable bow. These bows are best shot with a mechanical
release and require a little more practice for best long-range
accuracy. |
| |
 |
(32" to 38") Mid Axle Length
Bow
Mid axle length bows represent the majority of the market
and include most of today's most popular units. The mid-axle
bow offers a good blend of maneuverability and long-range
accuracy. Popular choice for recreational shooters, bowhunting
newcomers, 3D enthusiasts, and those who hunt from both the
ground and a treestand. |
| |
 |
(Over 38") Long Axle Bow
Longer axle bows are sometimes called "finger-shooter" bows,
as they offer a less acute angle at full draw for a more
comfortable finger release. Long axle bows are usually the
choice of serious competition archers and/or dedicated finger
shooters, but they are often considered "too long" for treestand
hunting. However, many shooters still prefer the added stability
of the longer axle bow. |
There is no right or wrong here either.
But the traditional wisdom is that longer bows are more forgiving,
stable, and accurate. This isn't to say that a short-axle bow
cannot be shot accurately. It just means that your technique will
need to be more exacting - particularly at longer ranges.
Nonetheless, the most popular bowhunting bows are 31-34" long.
Much like the market trend with a 7" brace height, bowhunters largely
regard bows under 31" as too short, and bows over 34" as too long.
There seems to be some magic in the 31-34" bow. The most popular
units of the last few years (Mathews Switchback, Bowtech Allegiance,
Hoyt Trycon, Browning Illusion, Diamond Liberty, etc.) all fall into
this axle-to-axle length range. So it's no surprise that nearly
half the bows on the market for 2007 now have similar axle-to-axle
lengths.
However, don't be swayed just by by what's popular. Not every bow
is suited for every shooter and purpose. For example, if you are a
finger shooter, the acute finger-pinching string angle at full-draw will
make holding back a short-axle bow quite uncomfortable. Most finger
shooters look for bows with at least a 38-40" axle-to-axle length to
avoid this problem. On the other hand, bowhunters who hunt
exclusively from a treestand often appreciate a small bow that can be maneuvered around shooting rails, tree limbs, etc.
So the right choice is the choice that's best for you.
With all that said, if you're a new shooter, or plan to shoot at longer distances, we
suggest you not choose the shortest bow you can find. Instead,
choose a more moderate length bow to help tip the forgiveness scales in
your favor while you learn the craft. |
 Speaking
of Forgiveness
Forgiveness is quite a buzz-word in archery. More forgiving bows,
more forgiving arrows, more forgiving arrow rests, etc. The term
would imply that you can do things wrong, and everything will still be
OK. Of course, this is a bit misleading. Even with the best
equipment money can buy, a shooter still must possess a certain amount
of skill. So when equipment is described as "forgiving", what does
that mean?
The term "forgiving" really means "forgiving to human errors", which is
something that isn't easily quantified - and the reason the term is used
so loosely. If we were to test a variety of properly-functioning bows
in a mechanical shooting machine, the varying axle-to-axle lengths,
brace heights, and cam characteristics would have no significant effect
on the accuracy and repeatability of the bows. The shooting machine
would shoot each bow exactly the same, each and every time.
Unfortunately, humans cannot shoot with such mechanical consistency. We
bobble; we flinch. We punch our triggers, or torque our grips. Even
for the world's most talented shooters, accuracy is often limited to the
occurrence of human error. And what makes a particular bow more or less
"forgiving" is the bow's tendency to accentuate or attenuate these
unavoidable human errors.
 Forgiveness
PerspectiveOf course, we
should keep the "forgiveness" issue in some perspective. Good technique
and a solid practice regimen are critical to success in the field,
regardless of which bow you ultimately choose. But the less forgiving
your bow is, the more exacting your technique will need to be. But don't
make more of this issue than need be. Within a typical 30 yard
bowhunting range, virtually any properly-tuned compound bow can be shot
with acceptable accuracy. And with a little practice, even a novice
shooter can easily bring down big game within this range. So if you hunt
in dense woods where 20 and 30 yards shots are common, your bow's
"forgiveness" just isn't such a critical consideration. But if you hunt
in more open country, where you must be able to reach out to 50, 60,
even 70+ yards, where the smallest glitch means a wound or a miss, you
should be more selective with the bow design you choose. |
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