Home / Guides / The compound bow

The compound bow

The compound bow uses a levering system of cams and cables so the archer holds only a fraction of the peak draw weight at full draw.

Cams and let-off

A compound bow has a cam or wheel at the end of each limb, linked by cables. As the archer draws, the cams roll over and the effort peaks, then drops away to a much lighter holding weight. That drop is called let-off, and it is often 70 to 90 per cent, so a bow that peaks at 60 pounds might hold at 12.

Let-off lets an archer hold at full draw long enough to aim carefully. The stiff riser and short, stiff limbs also make the compound the most mechanically consistent bow, which is why compound scores are so high.

What it means for the arrow

Compound bows shoot faster than recurves at the same marked poundage because of the cam geometry, so the arrow has to be matched to the bow's real energy, not just its holding weight. Manufacturers publish spine charts against peak draw weight and arrow length for exactly this reason.

Compound target arrows tend to be larger-diameter for line-cutting on the target face, while compound hunting arrows are smaller and heavier for penetration. Either way the spine has to suit the peak weight, which is what the fitment tool checks.

Release aids and sights

Most compound archers shoot with a mechanical release aid rather than fingers, which removes the sideways flex a finger loose puts into the string and lets a stiffer, more forgiving arrow tune cleanly.

A compound is aimed with a sight and often a peep in the string, and stabilised with long rods. The accessory side of this, how a sight or rest even attaches to the riser, is its own compatibility question covered by the sight and rest fitment work.

Related

Sources: World Archery: compound · Wikipedia: Compound bow