At any given position of the pulley, when stationary, the position of the nocking point depends on the relative strength of the springs only. This is usually called static tiller. If the pulley is pulled back and than released to accelerate forwards then the position of the nocking point point depends in addition on the mass of the springs, the moment of inertia of the pulley and the elastic properties of the string. The tension in the string will no longer be the same on each side of the pulley. This behavior is called dynamic tiller.

For a bow shooting an arrow the important tiller is the dynamic tiller. The mass and rotational properties of the arrow and the moving parts of the bow limbs will effect how the nocking point moves. (e.g. the mass of the bow limbs will affect the acceleration of the limb tips).