This paper presents an optimal, robust, adaptive tuning strategy based on a linear model predictive control (LMPC) scheme for the switching gain of a sliding mode control (SMC). The LMPC employs a moving horizon, where the dynamics of the sliding-mode-controlled system is addressed. The control design is presented exemplary for a DC drive which is subject to both nonlinear friction as well as model uncertainty. The overall control has a cascade structure. In the inner control loop for the currents, a flatness-based control is used. The outer control loop involves an integral sliding mode control of the angular velocity that is combined with a LMPC that adapts the switching height of the discontinuous control action.