I have
been asked many times about this issue and it is, in my opinion, that the
most important factor in making the decision when purchasing a compound for
the first time is, what do you want to do with it. I
have experienced, that the salesman behind the counter will sell you
what he has as apposed to what you need, and in many cases the application
of the bow is not considered as it should be.
Have a basic understanding of what you want to do with
a bow.
Over the years
I have bought and sold hundreds of bows. I have asked the same
question to every potential buyer, "What do you want to do with
the bow". I wait for there answer and at this point, I don't
give any choices. I allow them to tell me. This might be the
first time in your mind that you have an understanding of what
you want to do, and this is the first opportunity for me to
understand your needs. This is not a lecture on selling
techniques, however I think that it's important to know that a
salesman that rambles on and on about his product has only one
thing on his mind...his product. You as the customer now become
a distant second. The
information contained below is from Hunters Friend.
Well written with loads of good information and is a must read for all who
are choosing to buy a compound bow. I have added little bits and pieces here
and there in the attempt to fill a few gaps. To the author of this article
at Hunters Friend, A very well done job indeed. |
Introduction
Like many products, compound bows come in a variety of
shapes, sizes, colours, 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:
|
 |
 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. |
|
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. |
 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 draw stroke. 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. The longer draw length allows the bow
to place more energy into the arrow. 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# Draw Weight, 30" Draw Length, 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 animal 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 draw stroke (an important point for
later in our discussion). When finished, the graph shows
the amount of energy stored during the draw stroke, 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 Draw stroke
The curved line on the force draw curve represents the
bow’s draw stroke, commonly known as the power stroke. The
power stroke represents your effort. The power stroke
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 power stroke
depending upon its settings and cam characteristics.
Power strokes 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.
|
|
 |
 |
Draw Weight - Height
of the Power stroke
The primary method for increasing the amount of stored
energy during the power stroke 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.
|
Very Small Child
(55-70 lbs.) |
10-15 lbs. |
|
Small Child
(70-100 lbs.) |
15-25 lbs. |
|
Larger Child
(100-130 lbs.) |
25-35 lbs. |
|
Small Frame
Women (100-130
lbs.) |
25-35 lbs. |
|
Medium Frame
Women (130-160
lbs) |
30-40 lbs. |
|
Athletic Older
Child (Boys
130-150 lbs.) |
40-50 lbs. |
|
Small Frame Men
(120-150 lbs.) |
45-55 lbs. |
|
Large Frame
Women (160+
lbs.) |
45-55 lbs. |
|
Medium Frame Men
(150-180 lbs.) |
55-65 lbs. |
|
Large Frame Men
(180+ lbs.) |
65-75 lbs. |
|
|
|
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 power stroke. So properly set-up for best speed, a
60# version of most bows will perform within 10 fps of
the heavier 70# version.
|
Draw Weight - How Much
is Necessary
Some states in the US 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
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, 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. Imagine buying a pair of shows
that are either to small or to large, it's pretty much
the same thing - you can't use them effectively either
way. The correct draw length is of paramount importance.
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 foot 5" to 6
foot 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. To
measure your draw length is a pretty straight forward
thing to do. Stand with your back against a wall and
open your arms to the crucifix position. Have a friend
measure from the middle of your left hand, across your
chest to the middle finger on your right hand. Use that
measurement in the chart represented below. It can be
measured in inches or centimetres. To convert
centimetres to inches, divide by 2.54. Therefore a
measurement of 195cm / 2.54 = 76.62 (estimated at 30
1/2' draw). An important thing to remember when choosing
a compound bow is that the bow draw length adjustment
must be within the parameters of your draw length.
Choosing a bow that fits outside of your draw length
parameters would not be a good idea.
|
Finger tip to
finger tip measurement in Inches |
64 |
65 |
66 |
67 |
68 |
69 |
70 |
71 |
72 |
73 |
74 |
75 |
76 |
77 |
78 |
79 |
|
Estimated Draw
Length in Inches. |
24.5 |
25 |
25.5 |
26 |
26.5 |
27 |
27.5 |
28 |
28.5 |
29 |
29.5 |
30 |
30.5 |
31 |
31.5 |
32 |
Draw Length Affects
Power
The longer your draw length, the longer your bow's power
stroke 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 foot 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 power stroke will
be. Take a look at the additional sample graphs below,
taken from bows with different types of popular cam
systems. |
|
 |
- 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 power curve.
- 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. This cam is sometimes referred to
a a Go-No-go cam
|
|
 |
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
flaw in shooting-form). Aggressive hard-cams tend to have
the most narrow valleys since delaying the let-off
allows additional energy can be stored during the
power stroke. 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 on the shooting string. 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 if not all 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 power stroke
will be. And as you know, a longer power stroke
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 power stroke 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 power stroke 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
favoured
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 target, 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. You'll
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 noted earlier, a bow which has a 6"
brace height and is set for long 30" draw length will
have 22.25" power stroke. 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 power stroke 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, Springbok,
etc.) |
|
42-65 ft. lbs. |
Large Game (Kudu, Eland, Bush
pig, etc.) |
|
>
65 ft. lbs. |
Big 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, bone,
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 and arrow 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
favour 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 or both. 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. LET-OFF
is measured as a percentage of peak weight.
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, (The maths
is, 70 x 75% - 75 = 14#, or 20% of peak weight = 14#), 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 (hysteresis). 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
hysteresis.
|
 |
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.
|
Cam Type
Modern compound bows generally come with a choice of
3 or 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, rivalling 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 aluminium 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 tortional 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 by product 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 centre-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 do-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 sceptical at
first. But by 2005, high limb angle parallel style bows
were totally dominating the compound bow market.
 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 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 R 3000. So it seems that the
traditional D-shaped (banana) 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
enamoured by the lack thereof, they almost forget to
consider the bow's grip comfort, balance, and draw
stroke
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 bow hunter'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 (0.9Kgs). 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 centre 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:
| |
 |
(Under 32")
Short Axle Bow
Short axle bows are very popular with
short draw archers as well as treestand hunters and those who want a
compact, lightweight, and manoeuvrable 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 manoeuvrability 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. 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, 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 by just by buying 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 manoeuvred
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 favour 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
Perspective
Of 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 pin point
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. |
|
VIBRATION
AND NOISE |
 Cause
of Unwanted Vibration and Noise
The last thing that a Bowhunter wants to sacrifice is
stealth. A quiet bow can mean the difference in filling
your tag, or just telling the story of the one that got
away. There is no denying that some bows tend to be
quieter than others. But you might be surprised to
learn that bow noise is sometimes not from the bow at
all.
Before we can pick this issue apart, you should know a
little about why bows tend to make noise. The video
link at your right is a high-speed video of a bow being
fired. Watch the video carefully. Notice how the sight
flexes and distorts after the shot. Notice that the
entire riser seems to flex. Notice the string flopping
forward. Then take into consideration that this video
was taken from a state of the art parallel limb
bow, one of the best bows money can buy. Then imagine
what it would look like for a bow that wasn't built so
well.
If you study the video for a moment, it becomes obvious
why bows make noise. Noise is caused by vibrations in
the air. And as you can see, firing a bow causes
dramatic vibrations. When you fire your bow, everything
on your rig momentarily dances and blubbers around
violently: your limbs, your string, your sight, your
quiver, the arrows in your quiver, etc. The whole rig!
Of course, this all happens in a flash - so you don't
see it. But you can sure hear it and feel it. And the
more energy your bow has, the more vibration is tends to
create.
But...if the vibrations can be stopped quickly, before
they have a chance to create sound, the result is a
quiet bow. If the vibrations are allowed to continue and
die-out naturally, the string will continue to "twang"
and vibrations will transfer into the bow's riser and
accessories. Not only does this create a 'buzzing"
feeling in your hand (not recoil), the vibrations also
cause any loose parts on the bow to make noise.
Incidentally, in many cases shooters blame their bows
for being noisy when in fact the accessories -
particularly the accessory fasteners (screws) - are the
true noisemakers. A tube-aligned peep-sight is also a
common culprit for noise, as is a dirty cable slide.
Whisper Quiet Bows
With so many possible ways for noise to be created, it's
really quite misleading to advertise a bow as "whisper
quiet". Yet, every bow manufacturer tries desperately
to convince you that THEIR bows are the quietest. The
fact is, no bow is whisper quiet. Even the quietest
bows make a solid 70+ dB bark when they fire. But you
can help minimize noise by using only quality
accessories, installing good string silencers, carefully
maintaining your fastener torques, and keeping your bow
in good overall condition. And even with that, should
your new bow be a bit more noisy than you like, this is
where the rubber stick-on's, jiggly stabilizers, and
hydraulic whatchamacalits may come to the rescue.
We strongly recommend you consider noise a function of
your entire "bow system", rather than just the bow, and
prepare to tackle it accordingly. Noise reduction
begins with quality. Thoughtful construction, tight
tolerances, quality parts, good maintenance, a
professional setup, and strategic incorporation of
dampening technologies all combine to create the
quiet bow. It doesn't usually come straight out of
the box. |
|
SUMMARY
RECOMMENDATIONS |
Attributes to Consider
While weighing the different bow attributes boils down
to a personal choice, we you suggest you give some
attributes more consideration than others.
|
|
Not
Important |
Minor
Consideration |
Somewhat
Important |
Very
Important |
Critical
Consideration |
|
Brand Name |
|
X |
|
|
|
|
Draw Length |
|
|
|
|
X |
|
Axle to Axle Length |
|
|
|
X |
|
|
Brace Height |
|
|
|
|
X |
|
Cam Aggression |
|
|
|
X |
|
|
Cam Type |
|
|
X |
|
|
|
Let-Off Choices |
|
|
|
X |
|
|
Limb Type
(Split/Solid) |
|
X |
|
|
|
|
Power/Speed |
|
|
X |
|
|
|
Recoil (Parallel
Limbs) |
|
|
|
X |
|
|
|
If you
still have questions, we would be glad to help.
E-mail us your
concerns and comments,
or call us +27 21 511 66 10 |
|
|
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