Recommended Fits

Load in Relation to Fit

As the load on a bearing increases, the interference fit between inner ring and shaft will reduce due to the expansion of the inner ring under load. The effect is compounded when the load begins to rotate. Shaft and housing material must also be sufficient in strength to provide suitable support for bearings under higher loads. If the shaft and housing material deform to greatly under load the lack of support may cause the hardened ring of the bearing to fracture.

As a rule, the higher the load the greater the interference fit. In turn this may require stiffer bearing arrangements

Temperature in Relation to Fit

The expansion and contraction of a bearing within a variable temperature or high temperature applications will affect the internal clearances and any desired axial displacement of the bearing. Under higher temperature conditions the fit on the inner bearing will become looser and the fit on the outer ring will become tighter. Therefore, selection of fits is crucial to ensuring that the bearing will have sufficient clearance not to seize during the running of the bearing.

Bearing Internal Clearance in Relation to Fit

Due to the elasticity of both bearing rings and mating components tighter interference fits can cause deformation of the bearing rings, expansion of the inner ring or compression of the outer ring leading to the alteration of the internal clearance.  In excessive cases bearings may be provided with an increased clearance to compensate for the reduction incur by larger interference fits.