Polydisperse suspensions display lower viscosities as compared to monodisperse suspensions at the same solid volume fraction. The reduced viscosity associated with polydispersity can be explained by an increase with dispersion in particle size of the
jamming fraction, or maximum flowable fraction, of solids, φm. We work on studying the rheology of bidisperse and higher order polydisperse suspensions. Additionally, we find rheologically equivalent bidisperse suspensions
to commonly occurring polydisperse ones (right) and use it to better understand polydispersity effects.