In this paper, we have used commercial software ADAMS© and Matlab© to simulate a rider-bike-track in a downhill race. The bike suspension dynamic behavior was analyzed by developing a novel control algorithm denominated MTB for a semi-active suspension model. Nevertheless, the control algorithm is not the only original contribution of this work. Even though the semi-active model has been used in previous projects, to the best of our knowledge they have not included bike, rider and track as variables in the system. We have simulated the control actions the rider has to develop in a race with a specific track, feeding the model with some data from literature and others were obtained by direct measures. We have also included a simulation using the most referenced control algorithm, Skyhook, for semi-active suspension. This was done with the purpose of comparing this algorithm with the performance of our MTB algorithm.