I had a Recurve student write to ask:
“I’ve been thinking about compound bows, is it a big difference shooting one and another?
If I wanted to buy a compound bow what would you suggest? (Not that I’m going to buy one, I just want to check prices and everything else).”
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Oh … boy, oh boy, oh boy! There are big differences between compound bows although they all operate on the same principle. The basic design of a compound bow (there are many variations) builds in a mechanical advantage by not attaching the bowstring directly to the limbs. The bowstring is attached only to the “eccentrics” at each limb tip which can be as simple as a pulley with an off-center axle to fantastically complex freeform shapes, but which all have the same role. The eccentrics are connected to the limb at the other end of the bow through the means of a cable. When the bowstring is drawn, the eccentrics rotate and act as levers to bend the limb opposite via its cable. Once the rotation gets past a certain point, the force of the pull on the cable is thrown onto the limb and the only force required to keep the bow drawn is the force need to keep the eccentrics rotated, which is a small fraction (one fifth to one third typically) of the “peak weight” of the bow. Because of this “letting off” of some of the draw force, compound bows are made with substantially harder to bend limbs than recurve bows, allowing them to store more energy that other bows of the same draw force.
Pros and Cons of Compound Bows
• First of all they are quite a bit heavier than recurve bows. This makes them more stable when shot (improving consistency) but makes them harder to lift up shot after shot (especially for youths).
• Because of the letoff, the stress on the archer at full draw is much less and more time is available to aim.
• Because of the design of the bow, the bow has its own draw length! The string, when pulled, goes back only so far and stops. That “stop position” is adjustable and must be carefully adjusted to fit the archer’s draw length (which will be different from his recurve draw length, even if still using fingers on strings). Some bows have only slight DL adjustments (circa 1/2˝) and require new parts (draw length modules) to make larger changes. Most bows have several inches of DL adjustment, and some of the new ultra-adjustable bows have many, many inches of DL adjustments (and draw weight adjustments, too).
• Virtually all modern bows are designed to be shot with mechanical release aids, which have a technique all to their own to learn (it took me three years to master release technique).
• Most modern compound bows have been designed to be shot in bowhunting environments which means they are short … very, very short. The lengths of compound bows are measured from “axle-to-axle” (aka ATA). When compounds were first invented, the ATAs were 48-54˝. All of my compound bows that I shoot with my fingers on the string are in the 46˝ to 48˝ ATA range. Most modern compound bows are less than 35˝ ATA, which means the string is at a very sharp angle if you try to draw the bow with a tab and fingers. This sharp angle causes “finger pinch” which is very uncomfortable (not so much at full draw, but definitely at the “peak weight” of the bow you must go through to get to the more comfortable “holding weight”).
• Kid’s compound bows are often “zero letoff” meaning they don’t have their own draw length, they just keep going like a recurve bow (although typically the draw weight does not go up in the latter part of the draw). These bows do not have to be constantly adjusted to the ever increasing draw lengths of fast growing kids.
• By all means, try a zero letoff bow (e.g. a Mathews Genesis), their very low draw weight makes the finger pinch of these short bows endurable.
• If you want to try a “real” compound bow (aka one with letoff), ask somebody who is your height, as they will have a draw length roughly your own. You want a very (Very!) light drawing bow to try first and they are rare. If the someone you ask has a typical bow they will have a peak weight of 55# to 70# and you can hurt your shoulder just trying to draw such a beast. So ask someone what their draw length is and what their peak weight is. You are looking for something 45# or less. So, the prime candidate for you to ask is a tall woman. Most people are willing to let you give their bow a try, but if they say “no” they are not being rude, so do not take offense.
• This is very, very important (especially with modern bows). Once the bow reaches “peak weight” … let’s say #45 of force, it will rapidly become much less than that, say 15# at full draw. This is such a shock to people expecting for the draw to increase and increase as it does on recurves and longbows, that they are shocked and let go of the string, dry-firing the bow. This can damage the bow if you do it and will be really, really embarrassing, so on your first draw (always with an arrow), draw and let down, do not even give your fingers permission to open.
• If you are looking to buy a compound bow, I suggest investigating the ultra-adjustable bows first. You can turn the draw weight down to a very low value for learning and then up later. You need to make sure that the bow’s range of draw lengths includes yours! A bow I am currently reviewing is the Kinetic Rave bow which is built in Europe (where this student is located) and there are quite a few others. Beware! Not all draw weights are available at each draw length. I am aware of only one manufacturer who is claiming they are for their bow (the Parker bow company) but they haven’t returned any of my emails, so I can’t vouch for that. You can download the Owner’s manual for almost any bow now from the Internet and it is well worth the research to do so.
A Final Note
The best case scenario is to have a large archery shop nearby with a knowledgeable staff. If you tell them what your interests are, they can measure you up and show you some of your options, which you can also usually test shoot. Of course, they are not doing this for their health, they are trying to sell you something. So, don’t go and find the bow you want on the Internet for $10 cheaper and stiff your local vendor. The pre-sale service and post-sale service you are getting are usually invaluable. You do not get those through Internet purchases. And, if you don’t spend some of your custom at your local shop, there won’t be one soon (this is the predicament of this questioner—no shop, no range, no club nearby).