Load/unload techniques are widely used in mobile hard disk drives which have to endure external shocks frequently. ABS designs must consider both the load/unload performance and the shock resistance performance. Three ABS designs with different positions of the suction force center are studied in simulation. It is observed that when the position of the suction force center moves frontward, the anti-shock performance improves, but the unload performance degrades, and vice versa. A slider is not necessary to be designed to have its suction force center significantly behind of its geometric center, as the traditional load/unload sliders do. Instead, the suction force center can be designed near the geometric center if the hook limiter is used.