{"id":2824,"date":"2020-04-25T17:15:10","date_gmt":"2020-04-25T17:15:10","guid":{"rendered":"https:\/\/archerymind.com\/?p=2824"},"modified":"2022-05-07T22:08:49","modified_gmt":"2022-05-07T19:08:49","slug":"compound-bow-let-off","status":"publish","type":"post","link":"https:\/\/archerymind.com\/compound-bow-let-off\/","title":{"rendered":"What Is Compound Bow Let Off? A Detailed Guide"},"content":{"rendered":"\n

Let off is one of the most important features of a compound bow. It’s what allows compound archers to use much higher draw weights with high precision. In this post, we’ll cover the topic of let off, how it came to exist, and more.<\/p>\n\n\n\n

Let off is the percentage of the draw weight the archer holds on a fully drawn compound bow. A higher let-off means you hold less weight on a full draw, allowing you to aim comfortably even when using a high draw weight. <\/strong><\/p>\n\n\n\n

Let’s say, for example, you have a compound bow with a draw weight of 70 pounds, and let off of 75%. This means that when you pull the bow, through most of the way to full draw, you’ll pull 70 pounds. At full draw, 75% of the 70 pounds will be reduced, meaning you’ll only hold 17.5 pounds. This is huge.<\/p>\n\n\n\n

A standard compound bow will have let off of between 60% to 90%. These are just a rule of thumb though, and it does vary between different models. Some bows even have a feature of a changeable let-off percentage.<\/p>\n\n\n\n

But you’re probably wondering how let-off actually works on a compound bow. Let’s start by explaining the complex mechanics that are involved in achieving it.<\/p>\n\n\n\n

How does let off work?<\/h2>\n\n\n\n

This might be somewhat of a hard topic to explain, but the mechanics of the bow are what’s creating the let-off. I’ll try to use simple terms and intuition as much a possible.<\/p>\n\n\n\n

The way let off actually works is by the elliptical shape of the cams, which allow for more string to be pulled, and by the limbs of the bow being pulled closer. This creates a mechanical advantage, so the archer feels a lower weight.<\/strong><\/p>\n\n\n\n

The shape of the cams is designed to allow the right amount of string to be pulled when the archer gets close to the back wall. The cams rotate faster at that point.<\/p>\n\n\n\n

The limbs coming together is really the magic piece here. This allows for more of the weight to be put on the limbs, instead of being put on the archer.<\/p>\n\n\n\n

You can see how much force the archer need to exert to pull the bowstring in this famous graph:<\/p>\n\n\n\n

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So initially the archer doesn’t feel a lot of weight, but quickly the highest weight is achieved. At some point close to full draw, the weight curve shifts and it starts to decrease until let off is achieved. If the archer tries to pull the bow beyond this point, the poundage increases again (this is what’s known as “the wall”).<\/p>\n\n\n\n

Here’s a youtube video I found that explains how let-off works really well. I recommend watching it if you’re interested in the physics aspect of the concept.<\/p>\n\n\n\n

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https:\/\/www.youtube.com\/watch?v=34S707KKIPM&ab_channel=HaxenHunt<\/a>