A support assembly for a surface treating appliance includes a central roller arranged to engage a surface and outer rollers at either end of the central roller. The rollers together define a rolling support surface, and the outer rollers rotate about an axis spaced from the rotational axis of the central roller. This arrangement of rollers provides a rolling support surface over a wide range of motions, and spacing the rotational axes of the rollers permits the rollers to be arranged relative to one another to define a region into which components of the appliance are mountable.