What Is Compound Bow Let-off
The compound bow let-off is one of the most important aspects of compound archery for competitive shooters. It’s also something that many new compound archers are not familiar with, so they don’t know what to look for when purchasing equipment or how to adjust it. This guide will teach you everything you need to know about compound bow let-off and how it affects your shooting performance.
A compound bow let-off is the amount of pressure required to hold the string at full draw. If you don’t know what this means, imagine holding a weight in your hand and having someone slowly add more weight until it’s too heavy for you to hold any longer. This is compound bow let-off: how much force it takes to hold the compound bow at full draw.
To understand how compound bows differ from recurves and longbows in the way they function. Those other bows have a single string, and they draw all of their power from the limbs flexing. As a result, the string gets harder and harder to pull the farther you draw it back.
Compound bows also have limbs, but they’re much shorter than a recurve or longbow. They also employ cables and wheels, called cams, in generating stored energy that is eventually used to hurl an arrow. By using cams and cables which aid in the drawing process, a compound bow is able to drastically reduce its draw weight about one half to two-thirds of the way through the draw cycle.
Compound bow cam and limb at rest.
When the cams roll over, the draw weight drops, so an archer is holding considerably less weight at full draw than the peak draw weight.
Compound bow cam and limb at full draw.
The amount of weight reduction is used to calculate the bow’s let-off. That is, a bow with a peak draw weight of 70 pounds, that has a full-draw holding weight of 14 pounds, is a bow with 80-percent let-off. Fourteen pounds is 20 percent of the peak draw weight, which means 80 percent of the bow’s peak draw weight has been shed or let off.
Compound bows primarily used for hunting commonly have let-offs of 75, 80 or 85 percent. PSE in 2017 introduced its Evolution Cam, which boasts 90-percent let-off.
In the hunting world, the benefits of high let-off are clear. Heavier draw weights are favored for their ability to drive arrows through game animals. But an archer might have to draw a bow early to avoid being seen by a game animal, and then hold the bowstring at full draw for an extended period while waiting for that animal to present the perfect shot.
Holding just 20 percent of a bow’s peak draw weight at full draw while waiting for that shot makes the task much easier. Competition archers, on the other hand, don’t always like a huge amount of let-off. They feel they can hold a bow steadier with more weight at full draw, and so target compounds often have let-offs of 60, 65 or 70 percent.
Using a bow with 60-percent let-off, that archer pulling a maximum weight of 70 pounds would hold 28 pounds at full draw. Remember, a recurve archer with a 28-inch draw length, shooting a 70-pound bow, would hold all 70 pounds at full draw.
How To Make a Compound Bow With Let-off
Find Your Correct Draw Weight
Draw weight, basically, is how much force it will take you to pull the string back. A bow with a lower draw weight—say, 15 pounds—will be a lot easier to draw than a bow with a higher draw weight—say, of 65 pounds. Lighter bows are easier to draw back, but they shoot arrows more slowly, whereas heavy bows are hard to draw back, but they shoot arrows at greater force and speed.
Ideally, you want to find a bow that’s in your “Goldilocks” zone—one that’s not too light and not too heavy. When choosing a draw weight, it’s usually a good idea to go lighter, rather than heavier, especially if you’re new to archery. Your muscles will develop over time and with practice, at which point you can switch to a heavier bow. Everyone is able to handle different amounts of weight, but as a general rule of thumb, here are some guidelines for recommended draw weight:
Men and women between the ages of 18 and 21: draw weight between 15 and 30 pounds (with 20 or 25 pounds a reasonable starting point)
Women age 22 and above: draw weight between 20 and 35 pounds (with 25 or 30 pounds a reasonable starting point)
Men age 22 and above: draw weight between 25 and 40 pounds (with 30 or 35 pounds a reasonable starting point).
If you consider yourself particularly strong, you may want to go slightly above these weights, but—be careful! Being “over-bowed” is a thing that happens to a LOT of people, it’s not like lifting a weight once. If you have a 40-pound bow, every time you draw it’s like lifting 40 pounds. It gets tiring. Better to start low and build.
Find the Correct Bow Length
Bow length is sometimes called the axle-to-axle length. The length of your bow depends more on the type of shooting you do than your overall size. Shorter compound bows are usually recommended for hunters, for example—it’s easier to go through woods and brush with a shorter bow—whereas longer compound bows are usually a good match for target archers and 3-D aficionados.
There are, of course, exceptions to every rule, and you might find that you prefer a long bow for hunting or a short bow for target practice. Bow length is usually a little more important to archers using a recurve bow, and you have more options when you use a compound.
How does compound bow let-off affect performance?
There are a few factors in compound archery that play into how accurate and powerful your shot will be when you pull the trigger or release your arrow from the string: brace height, anchor point, aiming technique, form consistency , follow through…they’re all important. But compound bow let-off is the only factor that you have complete control over when shooting, so it’s one of your most powerful tools to affect accuracy and consistency in compound archery.
Different equipment has different compound bow let-offs: some are extremely low (20 or less pounds) while others are higher (50 or more pounds). The compound bow let-off is usually printed somewhere on the limb or riser of your compound bow, and it’s also listed in the instruction manual.
Take a few minutes to familiarize yourself with what compound bow let-offs look like so you can quickly identify them when shopping for bows online:
If you are shopping online, compound bow let-off is usually listed in the product description or specs. You can also check out our compound bow buyer’s guide for more information about compound bows and what to look for when buying.
Does let off affect arrow speed?
In general, let-off does not affect the speed of your arrows, it only affects the draw weight behavior at full draw. The forces that push the arrow throughout its path, until it leaves the bow, are mostly the same for any let-off percentage.
The main reason for this is that most compound bows these days use hard cams. These cams, unlike soft cams, don’t speed the arrow up gradually.
This means that the let-off percentage, on most bows, only affects a short part of the arrow path close to the back wall. The difference in speed is typically less than 3 fps, which is tiny.
What effect does letting off have on accuracy?
The greater your compound bow let-off, the less force it takes to hold the compound bow at full draw, and therefore your groupings will tighten. This is because holding an arrow on target with a compound bow requires more force than drawing it back: you’re pulling against yourself when aiming if you’re not using one of our best recurve bows for beginners .
Most compound shooters aim by simply looking at their target, holding the compound bow in line with it. If you have a compound bow let-off of 50 pounds and are aiming at your target, when your arrow is nocked on the string (drawn) you’ll pull 70 pounds (50 + 20). But if there’s an obstacle between you and your target that would make it impossible to shoot, you can release the compound bow and it will drop down 30 pounds (50 – 20).
What effect does letting off have on power?
With compound bows having compound bow let-offs of 50 or more pounds, they are obviously powerful enough for most hunting situations. The main factor that affects how much energy is transferred into your target is your arrow speed.
The compound bow let-off does not affect how powerful the compound bow is: this comes down to draw weight and string height (more on that later).
If you’re looking for more power than what compound bows offer, read our guide about recurve vs compound bows.
What effect does letting off have on comfort?
When your compound bow has a high compound bow let-off, you can aim comfortably even when using a high draw weight. This means that you’ll be able to hold the compound bow steady for longer periods of time without tiring yourself out too much, and it also makes it easier to maintain focus while aiming.
If your compound bow has a compound bow let-off of 50 pounds, you can aim comfortably at your target with up to 70 pounds (50 + 20)
If the compound bow that you’re looking at buying has adjustable let off, always remember to check what its minimum and maximum settings are. For example: if your compound bow is set to maximum compound bow let-off, you’ll be holding it at full draw with 70 pounds (50 + 20) of compound bow let off.
But if you set the compound bow to minimum compound bow let-off, your compound bow will drop down all the way to its brace height when fully drawn: this means that instead of pulling 50 pounds or more above your compound bow’s brace height (the minimum amount of weight that you need to hold at full draw), you’ll be pulling only the 20 pounds or less of your compound bow’s brace height.
If you’re not sure what your compound bows’ let off is, check out our extensive guide about compound bow settings.
What effect does letting off have on a compound bow’s brace height?
The compound bow let-off is going to affect your compound bow’s brace height. A compound bows’ brace height refers to how much space there is between the string and where it attaches at each end of the limbs when fully drawn: think about this as being similar to draw length, as it limits how far you can draw your compound bow back.
- A compound bow will have a shorter brace height when its compound bow let-off is higher, because there’s less force pulling the string towards the attachment points of the limbs at each end. This means that if you’re looking for a compound with high accuracy and power, be sure to find compound bows with compound bow let-offs of 50 pounds or more to get the best out of it.
Here are some other points to keep in mind when looking for compound bows:
- compound bows having lower compound bow let offs will have higher brace heights, meaning that they’ll be easier to aim and hold steady than high compound bow let off compound bows.
- compound bows having adjustable compound bow let offs will have their minimum and maximum compound bow let off settings displayed somewhere on the riser of the compound bow, usually next to where you attach your arrow rest.
When should I use a low compound bow let-off?
If there are no compound bows that have compound bow let-offs of 50 pounds or more, don’t worry it’s not the end of the world. Compound bows with compound bow let-offs below 50 pounds are still extremely powerful and accurate enough for hunting purposes: you’ll just need to draw them back a bit further than what compound bows with higher compound bow let-offs require. A compound bow with a compound bow let off of 20 pounds or less will have the same brace height as your full draw length.
How can I adjust my compound bows’ let off?
If you want to change how much compound bow let-off your compound takes on, all you need is some Allen keys and a compound bow specific toolkit. These should be included in the compound bow’s accessories, but if not you can purchase them separately from most archery stores.
A compound bows’ let-off is generally changed by adjusting how much space there is between where your string attaches to each end of the limbs at full draw: this will also affect compound bows’ brace heights. If you need help changing your compound bow’s let-off, check out our compound bow settings guide for more detailed instructions .
What is the minimum and maximum compound bow let off?
The compound bow let-off can be adjusted within certain limits: these limits mean that a compound bows’ minimum and maximum compound bow let off are usually within the range of 20 to 70 pounds. A compound bows’ minimum compound bow let-off is often displayed somewhere on your compound bow, for example next to where you attach an arrow rest.
What Is A Good Let Off?
A compound bow let-off of between 30 and 50 pounds is considered a good compound bow let off. In general, the lower your compound bow let-off, the more accurate you can be with adding pressure to your shot before firing it when hunting or competing against other shooters in an archery tournament . A higher compound bow let-off means that you will have to add more pressure on the string before firing your shot, so it takes longer to get back into shooting position.
It’s also important for compound bow let-offs to be consistent across all draw lengths and weights, which is why most compound bows are designed with a set compound bow let off that does not change when adjusting draw length or arrow weight. Any compound bow let off that changes when changing draw length, draw weight, or arrow weights is not considered a good compound bow let off for hunters and compound archers.
What Is A Good Compound Bow Let Off?
- compound bow let off between 30 to 50 pounds considered good for hunting or shooting competition, but lower compound bow let offs are more accurate.
- compound bow let offs should be consistent when changing draw length, weight and arrow weights to ensure that the compound bow is accurate regardless of setup.
What Is A Bad Compound Bow Let Off?
- compound bows with compound bow limb movement are not considered good because they can cause inconsistency in accuracy and power. Read why here: compound bows should not move when shot.
Compound Bows Limbs Do Not Move
- compound bow limbs are designed to stay in the same position when fired, but compound bows with compound bow limb movement can be inaccurate and inconsistent depending on how they’re set up. Learn more here: compound bows should not move when shot.
- compound bows that move compound bow limbs are typically not as accurate and consistent as compound bows with fixed compound bow limb movement.