·To adopt the structure of double row innerrings,the angle which fills the ball isbigger than others,the auto wheel hubbearings can bear beavier axial and radialload.it is no need to adjust the innerclearance because it is already preserved inmaking.It was filled with Iubricating greasein high quality in the inner bearing,whichcould make the assemblage and usageeasily.The range of the diameter of the innerring is from 20 to 80mm and that of the outerring is from 40 to 120mm.Now there are morethan 300 kinds of this bearings.