A method of improving the pivoting of a wheel set for a scientific instrument, including an arbor pivoting or oscillating about a wheel set axis, is provided. A static balancing of this wheel set is performed to bring the center of gravity onto this axis. A desired value is determined for the resulting unbalance moment of this wheel set about this axis, corresponding to a predetermined desired divergence between a first principal longitudinal axis of inertia of this wheel set, and this axis. This wheel set is set in rotation at a predetermined speed about this wheel set axis, and the resulting unbalance moment is measured with regard to this axis. An adjustment is made to the value of the resulting unbalance moment of this wheel set about this axis within a given determined tolerance with regard to this desired value.