30mm Ceramic Hybrid Rear Axle Bearing - 30mm Ceramic Hybrid Rear Axle Bearing 30mm x 62mm x 30mm rear axle bearing Ceramic Hybrid Bearings have Steel races and Ceramic Balls. In ball form, ceramic is harder than steel and because ceramic balls are non-porous they are virtually frictionless and capable of spinning faster and with less drag than steel balls as well as being more durable.