In this paper, a simple control methodology is proposed to stabilize the position of the sprung mass of the quarter car system. The simplicity of the structure of the proposal facilitates the application in real systems. Such methodology allows five different continuous sliding-mode controllers to be selected by means of two similar designs to mitigate the chattering effect. These robust controllers ensure the exponential stability of the sprung mass of a quarter car system in the presence of some class of non-vanishing disturbances. The closed-loop stability is guaranteed by means of a Lyapunov function approach and Input-to-State Stability properties. Some simulations and comparisons show the effectiveness of the proposed control schemes compared to a classic linear approach. Additionally, some experimental results show the effectiveness of the proposed controllers in the Quanser Active Suspension System.