Generally speaking, ceramic bearings are not suited for cycling. In industrial or medical equipment applications, where the rpm is high, the load is low and the operating conditions are clean, ceramic bearings perform well. However, that is not the case in cycling, where bearings are highly exposed to high loads and the ingress of water and dirt. The optimal ideal rating of ceramic bearings is 10.000rpm+. In cycling hubs applications, the maximum rpm may be up to 500-600rpm, (road wheel at 35km/h is 265rpm). In these conditions, the advantage of ceramic bearings is negligible and does not provide a performance benefit for cycling as many people and companies claim they do. Another issue is the hardness of ceramic balls. The shocks of hitting potholes and other road bumps impact the hard ceramic balls into softer steel races, which eventually get dented and lose their smoothness. This causes drag and short service life.