The components of the nuclear inertia tensor, functions of the separation distance R and of the radius of the light fragment R 2 , BRR(R,R2) , BRR2(R ,R2) , and BR2R2(R,R2) are calculated within the Werner-Wheeler approximation, by using the parametrization of two intersected symmetric or asymmetric spheres. Analytical relationships are derived. When projected to a path R, = R, (R) , the reduced mass is obtained at the touching point. The two one-dimensional parametrizations with R2 = const, and the volume V 2 = const previously studied, are found to be particular cases of the present more general approach. Illustrations for the cold fission, cluster radioactivity, and cu decay of 2 5 2 ~ f are given.