This paper addresses the problem of motion planning of tracked vehicles. It is shown that the force equilibrium perpendicular to the tracks introduces a non-integrable state dependent equality constraint, making the path planning problem nonholonomic. A method is then presented for computing the nominal driving track forces for motions along a specified path at desired speeds. It consists of selecting the angular speeds along the path that satisfy vehicle dynamics and the non-integrable constraint. The computation of the angular speeds is formulated as a parameter optimization, minimizing the violation of the equality constraint. The method is demonstrated for motions along a circular path.