Consider a flywheel whose mass $M$ is distributed almost equally between a heavy, ring-like rim of radius $R$ and a concentric disk-like feature of radius $R/2$. Other parts of the flywheel, such as spokes, etc, have negligible mass. The best approximation for $α$, if the moment of inertia of the flywheel about its axis of rotation is expressed as $αMR^2$, is _______