Of the two, lateral dynamics has proven to be the more complicated, requiring three-dimensional , multibody dynamic analysis with at least two generalized coordinates to analyze. At a minimum, two coupled, second-order differential equations are required to capture the principal motions.  Exact solutions are not possible, and numerical methods must be used instead.  Competing theories of how bikes balance can still be found in print and online. On the other hand, as shown in later sections, much longitudinal dynamic analysis can be accomplished simply with planar kinetics and just one coordinate.