Fit and preload of NSK wheel bearings

Axial clearance and fit are specified to allow NSK wheel bearings to operate within an optimal preload range (life, rigidity, creep, and heat generation).

Fit and preload

The preload must be pre-adjusted based on the fit with other components and nut clamping force, which reduces axial clearance.

For calculating tolerances, NSK has standard preload settings of zero to negative dearances using the 30 method and maximum preload of 9800N using the direct sum method.

Recommended fitting measurements

Type Housing Shaft
HUB 1 Inner ring rotations T7 -0.064
m6 +0.025
Outer ring rotations -0.061
HUB 2 Inner ring rotations - m6 +0.025
Outer ring rotations - Loose
HUB 3 Inner ring rotations - -
Outer ring rotations - -

1) The dimensional tolerance of the diameter between inner rings and outer rings of NSK hub unit bearings is in compliance with JIS0.
2) Excessive fastening by fitting bearing inner rings may cause defects (high pressure, deformation of pressed surface, plastic deformation, cracking of inner rings). Check to see that the maximum stress on the inner rings does not exceed 147 MPa.

Fitting tests

when mounting NSK wheel bearings on vehicles, use actual components to confirm that the axial clearance is properly set and the preload is within the appropriate range as specified by the users.

  Components Usage conditions Knuckle (housing) Hub CVJ Spindle (shaft) Nut washer Snap ring Others (sensor rotors, etc.)
HUB 1 Driven wheels Inner ring rotations 6 6 6 - 18 6 -
Non-drive wheels Inner ring rotations 6 6 - - 18 6 -
Outer ring rotations - 6 - 6 18 6 6
HUB 2 Driven wheels Inner ring rotations - 6 6 - 18 - -
Non-drive wheels Inner ring rotations - 6 - - 18 - -
Outer ring rotations - - - 6 18 - 6
HUB 3 Drive wheels Inner ring rotations - - 6 - 18 - -

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