Crossbow Bow Technologies
Recurve crossbow technology has been around since the dawn of time. Well, pretty much anyways. It has been documented to be known to exist from somewhere around 6,000 BC. So it’s a pretty safe assumption that it is the oldest technology when it comes to the limb configuration of a crossbow. The recurve limb design is very simple, and yet very effective. It has proven itself to be a reliable platform for the function of propelling and arrow. As a matter of fact, one major crossbow manufacturer has had a 25 year plus run at making only recurve crossbows.
Recurve crossbows can be very appealing because they are easy to maintain. They only have one string that connects the limbs tips, and have no other moving parts. Recurve bows tend to be less front heavy because they do not require a large riser for mounting the limbs, in conjunction with not having the extra weight of the wheels or cams like a compound bow would have. One main advantage of a recurve bow is that the crossbow hunter or shooter can change his or her own string without the use of a bow press. This fact alone has led to many hunters choosing the recurve platform because they can do maintenance themselves without having to take there bow to the local archery shop.
Todays modern recurve crossbows are capable of reaching the same performance and speed as the compound crossbow. However, in order to achieve comparable speeds, they require shooting a lighter weight arrow while at the same time increasing the overall draw weight or poundage of the bow. You can find various recurve models starting at the 150 pound draw weight range and climbing all the up to the 275 pound draw weight range.
One potential area of concern when dealing with recurve bows is that because they have a heavier draw weight than most compound crossbows, they are also harder to cock. Especially when you take into consideration that recurve bows do not have a let off like compound bows do. As you continue to pull back on the string of a recurve bow, the overall draw weight continues to increase. They reach their full draw weight at the end of the power stroke when the bow is fully cocked. As a result, shorter framed hunters, women, and or children, tend to struggle cocking the recurve crossbow without the use of a cocking aid.
If a hunter is physically able, a recurve crossbow can be cocked by hand, but it is still a chore for even the most able body hunter. The use of a rope cocking aid, which cuts the overall draw weight by 50% can be a huge asset when choosing a recurve crossbow. If more help is still needed, there is one major recurve crossbow manufacturer that offers a crank style cocking aid which takes very little effort to cock a recurve bow with.
Another area of concern can be the overall width of a recurve bow. Most of todays recurve crossbows measure in right around the 36” wide mark. This makes them a good bit wider than most of the compound crossbows. So depending on what type of terrain you are hunting, you may want to consider how easy it will be to navigate while toting a 3’ wide bow in your hands.
Compound crossbow technology of one type or another is the most widely used platform with todays modern crossbow manufactures. A compound crossbow will have two limbs and a string like recurve bows do. However they also have two wheels, often referred to as cams, and two cables. There are many configurations of how the strings, cables, and cams all work together, but they all pretty much have the same principle. Compound bow technology works as follows. The cams are attached to the end of the limbs. The string is attached to the cams on one side, and the cables are attached at the other side of the cams. Depending on what type of compound bow configuration your crossbow has, the cables will either run from one cam over to the opposing cam, or they can run from one cam over the the opposing limb. Each way has it’s own advantages. When the string is drawn away from the bow, the cams rotate, compressing the limbs. Unlike recurve bow technology, the compound crossbow limbs will reach their full draw weight at some point in time during the draw cycle, but then relax to a lighter draw weight before the bow is fully cocked. Because off this let off, a compound bow is much easier to cock than a recurve bow making the compound bow technology more widely used in todays crossbow market.
Another advantage for compound crossbow technology is it’s performance. Because engineers have learned to configure the shape of a cam to be as efficient as possible, compound crossbows can have a lower draw weight then a recurve bow and actually shoot an arrow faster.
And still another advantage is the overall width of the compound crossbow being narrower. Because a crossbow string has to move a certain distance from its resting position when the bow is uncocked to its position when fully cocked, there has to be a way for the string length to become longer. With a recurve bow, the only way to gain the extra length needed is for the limb tips to move towards each other creating slack in the string that is then taken up by raising the string to the trigger mechanism. Because of the amount of distance the string needs to move the limbs need to be longer in order to flex enough, as a result creating a wider bow. On the other hand, because a compound bow has cams on it that the string is wrapped around, as the string is pulled and the limbs flex towards each other, the cams also rotate allowing extra string to roll off of them providing the string enough length to reach the trigger mechanism with a lot less limb movement. This allows the limbs to be much shorter in width as compared to the recurve bow.
There are three major configurations of compound crossbow technology varying in the relation of the cams to the limbs. Let’s take a look at all three and discuss their respective advantages along with their disadvantages. In order to make sure I don’t loose you when describing each particular version of compound bow configurations, lets assume that for each summary, that the crossbow will be pointed away from us.
The conventional compound bow is the most widely used technology when dealing with todays compound crossbows. The limbs are mounted to a riser which is then mounted to the end of the rail or barrel. The cams are mounted to the end of the limbs with the string being closest to the trigger assembly and the cables in front of the string. The string comes off of the outside of each cam as a result, leaving you with a wider string angle when the bow is fully cocked. Because of this wider string angle , the conventional crossbow can be cocked by hand without pinching them against the rail. A rope cocking aid or a crank style cocking aid, if available from your bows manufacturer, can also be used. Conventional compound bow technology can result in a slightly overall length when compared to the other types of compound bow technology due to the location of the string. In order to get the maximum power stroke from the conventional style compound bow, normally the rail or barrel will need to be longer. This moves the riser further out in front of the crossbow making it feel a bit more front heavy.
Inverted cam technology is the second form of compound crossbow technology. These types of bows have the riser and the limbs mounted the same way as a conventional crossbow would, however the cams are inverted so that the string is on the opposite side of the cams closer to the foot stirrup. The advantage of inverted cam bow technology is that because of the strings configuration, the bow automatically gains a couple of inches of power stroke, which leads to increased arrows speed, or the overall length of the crossbow can be shortened by a couple inches and still maintain the same speed as a conventional compound crossbow with a longer power stroke and overall length. The disadvantages are now because your string is coming off of each cam from between each other as opposed to from the outside of each other, your string will have a sharper angle. This sharper angle starts to effect a couple things worth pointing out. If you are the type of hunter than doesn’t want to use a cocking aid, the steeper string angle will now pinch your hands against the rail when cocking your bow. A rope cocking aid is almost a necessity at this point. Also, because of the steeper angle that the string comes off of the cams and comes around the latch of the trigger mechanism, you can start to see some increase serving issues. With crossbow strings, the sharper the angle the string has to bend, the more the serving will want to separate over time. Unlike the recurve bow, this will require a costly bow press or a trip to your local pro shop in order to maintain.
The third form of compound crossbow technology is called reverse draw technology. Reverse draw bow technology, often referred to as RDT, is completely different from the first two types of compound bow technology. While it is still very much a compound system, the riser is no longer mounted at the end of the rail, and the limbs are no longer drawn towards the shooter. With reverse draw crossbow technology, the riser is mounted somewhere between the center of the rail and the very back of the rail where it meets the stock. The string is oriented like the inverted cam bow technology with it being located in front of the cams. Reverse draw bow technology has a few very nice advantages over the other two compound bow technologies. First, because the riser is mounted behind the string, the string can now be located almost all the way forward at the end of the rail or barrel resulting in some very long power strokes without compromising the overall length of the crossbow. With the extra power stroke that is gained, reverse draw technology bows can achieve blazing speeds at draw weights lower than any other type of bow technology. And because of the position of the riser, the overall balance of the crossbow can be better because of the shift in weight towards the center of the bow. Another great feature is because the limbs face forward, and are almost parallel with the barrel, they work against each other when the bow is fired, canceling out much of the vibration and noise. While there is not one truly “quiet” crossbow, the RDT crossbows tend be some of the quietest on the market today.
Reverse draw technology bows do have a very steep string angle when the crossbow is cocked. Mainly because to accommodate the further distance the string must travel because of the longer power stroke, oversize cams are needed to allow for more string to be released while going through the draw cycle. These oversized cams come very close together when reverse draw technology bows are cocked, creating the very acute string angle. It is so acute, that it will require a cocking sled to cock a reverse draw technology bow. A cocking sled is a piece of aluminum attached to a rope cocking aid that is machined to fit over the rail of a crossbow and guides the string back until the bow is fully cocked. Without the cocking sled, it would be almost impossible to cock some of the reverse draw technology bows. As stated in the inverted cam bow technology section, the steeper the string angle, the more issues with string servings you may have. RDT bows have the steepest string angles of all.
Wow! We’ve just covered a lot of information. If you’ve made it this far through the crossbow technology article, you should have a pretty good understanding of how each type works and some of the advantages and disadvantages of each type. Which technology you choose is really up to you as an individual and should is a personal preference. There is no wrong choice. Choose the one that will best suit your needs for the style of bow hunting you will do.
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