  Using the Belle detector we study the characteristics of beam collisions at
the KEKB 3.5 GeV $e^+$ on 8 GeV $e^-$ asymmetric energy collider. We
investigate the collision timing {\tip} and its $z$-coordinate along the beam
axis {\zip} as a function of the position of the colliding bunch in a beam
train. The various {\tip} and {\zip} behaviors observed by Belle are attributed
to beam loading effects in the radio frequency cavities that accelerate the
beams with a beam abort gap. We report these results in detail and discuss the
prospects for the SuperKEKB collider.
