The single row tapered roller bearings can only carry the axial force of one direction. So two sets of bearings must be used together. Double row and four row bearings can carry radial-axial combined loads with the radial loads as main on and can carry axial load of two directions.

This type of bearings doesn't allow the inclination of shaft to housing. The amount of the axial clearance has something to do with the normal operation of the bearings. When the axial clearance is too small, the temperature will be higher, when the axial clearance is too big, the bearings are easy to break down, therefore the axial clearance of single row bearings must be set well in mounting. The clearance of couple row and four row bearings has been well set before leaving the factory, so it is not necessary for the customers to make farther adjustment.