Compound Bow: How It Works & Key Components

A compound bow is a modern bow that uses a system of cams (pulleys) and cables to bend the limbs and store energy more efficiently than a traditional bow. First introduced in the 1960s, it has since become a widely used option across hunting, target shooting, and competitive archery.

How a Compound Bow Works

When an archer draws the bowstring, the limbs flex and store energy. As the draw continues, the eccentric cams at the limb tips roll over and reduce the holding weight at full draw — a mechanical advantage called let-off. Let-off can reach as high as 90%, meaning an archer may hold only a fraction of the bow's peak draw weight once fully drawn.

Compound bows also feature defined draw stops: part of the cam contacts a limb or cable at the end of the draw cycle, ensuring a consistent power stroke from shot to shot. This repeatability is one reason the modern compound bow is valued for accuracy.

Key Components of a Compound Bow

Riser

The riser is the central grip section of the bow, typically machined from aluminum or magnesium. It anchors the limbs and serves as the mounting platform for accessories.

Limbs

The upper and lower compound bow limbs flex during the draw cycle, storing and releasing energy. Most are constructed from fiberglass or carbon fiber composites and attach to the riser via bolts seated in limb pockets.

Cams and Cables

Cams sit at the tip of each limb and drive the mechanical advantage system. Common configurations include single cam, dual cam, and hybrid cam — each with different draw-cycle characteristics. The bowstring cables connect the cams and limbs, transferring stored energy to the arrow at the shot.

Accessories

Optional additions such as sights, stabilizers, quivers, and arrow rests can be mounted to the riser to improve consistency. None are required, but each targets a specific aspect of shooting performance.