I assume the reference to egg beater just means the standard flip over two sided spd type pedal, rather than egg beater brand that are very different visually, and so I reckon the problem is that the original pedals may have been SPD-alike rather than SPD and though supposedly 'compatible' this 'shimano comaptible' bit is just the 2 bolt cleat mounting to fit SPD shoes, I had WMD? pedal/cleats and they worked fine together but a shimano pedal wouldn't take these cleats but a shimano cleat would fit the pedals albeit very BADLY so I wonder if one of the components is a copy?