Adding mass to a bow affects the tuning of the bow and will typically causethe arrow to act a bit stiffer. It's not that it changes the spine of the arrow, but it affects the dynamics of the bow during the shot. The slide on quivers usually have more an affect than the ones that bolt onto the risers. With the slide on quivers, you've got two things going on. The first is determinedbyhow far down you slide it onto the fade. The closer youslide it downtoo the riser, the less itaffects limb movement and energy transfer to the arrow.Conversly, the further up the limb the quiver is placed, the more of an effect is has on limb movement. It's like adding mass weight to the limbs. The other isadding mass to any bow affects the movement of the bow during the shot. When you release the string, the arrow isn't the only thing thatmoves and flexes. The whole bow does, not just the limbs, to a certain degree. This movement, even though slight,plays into arrow clearance.Increasing the mass weight of the bow changes the way the bow itself reactsby decreasing the effects of residual energy andthings likebow hand torque.