The wheel hub ball bearing include the wheel bearing with grooved ball bearing,with A central ball bearing and Two central ball bearings.The wheel bearing with grooved ball bearing (also called a precision ball bearing) meets high standards in terms of load capacity, rolling characteristics (even at high speeds) and resistance to environmental factors. Grooved ball bearings have the lowest level of bearing clearance, and are mainly used in technically-demanding transport unit castors and heavy-duty castors. The wheel bearing with two central ball bearings provides a high level of precision and smooth running performance. It also provides an effective seal while meeting demanding load capacity requirements.