Adjustment means setting the bearing internal clearance (→ Mounting) or preload in a bearing arrangememt.
The radial preload typically used for cylindrical roller bearings, double row angular contact ball bearings and sometimes for deep groove ball bearings, for example, is achieved by an interference fit on one or both bearing rings. The degree of interference should reduce residual clearance to zero, which is further reduced to a negative clearance (preload) when the bearing is in operation.
Bearings with a tapered bore are particularly suitable for radial preloading since, by driving the bearing up onto its tapered seat, the preload can be applied to within narrow limits.
Axial preload in a bearing arrangement with single row angular contact ball bearings, tapered roller bearings and deep groove ball bearings is produced by displacing one bearing ring axially, relative to the other, by an amount corresponding to the desired preload force. There are basically two principal methods to adjust preload: individual adjustment and collective adjustment.