The aim of this work is to improve the performance of a racing motorcycle by means of gearbox tuning. The Optimal Maneuver Method, which essentially simulates an ideal driver and computes the minimum Lap Time for a given motorcycle and a given circuit, is applied. A 1000cc SuperBike motorcycle and two very different racetracks, i.e. a fast one and a slow one, are considered. First the agreement between the Optimal Maneuver Method results and the logged telemetry data is proven, in order to fully justify its application. Next the relationship between gearbox ratio, lap performance and circuit characteristics is investigated and potential improvements are highlighted. Finally gearbox tuning is achieved by a Lap Time optimization procedure, and subsequent performance improvements are discussed.