What Does Let-Off Mean On A Compound Bow?
When buying a compound bow there are many terms that are listed among the bow’s specifications. These terms help those who are familiar with compound bows by indicating the size of the bow, the amount of power it has, the speed at which it can shoot and the accuracy you may expect to be able to achieve. One of the terms that is always mentioned is the let-off, sometime it will be referred to as effective let-off and the adjusted let-off may also be quoted. So the questions must arise in the mind of someone who is new to the sport, what does let-off mean and how will it affect my decision on which compound bow to buy?
Let-off is the biggest benefit that is gained through the pulley and cam system that helps to draw a bowstring back. It is a measure of the draw-force that has to be exerted when compared to the starting draw weight. When drawing back the bowstring on a compound the pressure required to pull back the bow will be quite high. As the draw progresses, the pulley system comes into play and the weight quickly drops off so that a lot less force is required to hold the bow at full draw.
The term let-off, then, refers to the size of the decrease in the required draw-force when the bow has reached full draw. If the draw is illustrated in graphical form, we will see a gradual rise in draw weight until a certain point in the draw before it suddenly drops down. The result is that the archer only has to exert a fraction of the energy to hold the bow at full draw compared to what they might otherwise have to hold should there be no let-off.
If you take a look at the specifications of a compound bow you will find that the Let-Off is specified as a percentage. For example, the quoted let-off for a Hoyt Carbon Matrix is 70%. What this means is that when the bow is at full draw the archer will be holding 30% of the total draw weight. So if the archer is shooting a 70lb Carbon Matrix, at full draw the archer will only be holding 21 pounds.
You may find that the majority of today’s compound bows are set up by the manufacturers at one of two standard let-off levels. These are either 65% or 80%. Experienced shooters will have a preference for one or the other of these levels, although it is also possible to adjust your compound bow to whatever level suits you best.
Some shooters prefer to use a bow that has a heavier draw because it feels more stable when it is held at full draw. You might see or hear shooters talking about a solid back wall when the bow is at full draw. They believe that the added tension in their stance aids their accuracy. On the other hand, other archers prefer a bow with a higher let-off setting so that they can feel more relaxed when at full draw. The lower holding weight might mean that they are able to concentrate more fully on sighting the bow without feeling as though they are fighting with the bow.