The tiller is the difference in the normal distance between the bowstring and the upper and lower limbs, noticeable due to the different thicknesses of a bow's limbs. It is measured at the point where the limb enters the limb sockets (limb pockets) of a sports bow's riser. The tiller is a value that indicates the ratio of the tension between the lower and upper limbs. The manufacturing or adjustment process is called tillering.
Because the recurve bow is usually supported (gripped) in the handle and its geometric center, it is not possible to bring the energy/power center of the limbs and the pivot point or force introduction of the bow hand to one point.
The center of force of the bow, the center of gravity, is located approximately 35 mm to 45 mm above the pivot point or the symmetrical center axis, depending on the design of the bow system or the riser. The archer's specific pressure point position shifts the theoretical pivot point upwards or downwards depending on the hand position or the chosen grip geometry, which influences the limb synchronization.
The grip position of the bow hand dictates that the arrow rests above the axis of symmetry. However, in order for the limbs to enable a synchronized arrow release—that is, to transfer a consistent force and optimal acceleration to the arrow—the force geometry of the limbs must be adjusted accordingly. One option is to select the limbs with different strengths accordingly, or to adjust their angle of attack in the limb pocket of the riser, which is achieved by adjusting the upper tiller.
.png?h=64&w=200&mode=max&scale=canvas&format=webp&quality=90&autorotate=true){kind=logo}
.png){kind=logo}