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68 mm bore bearings

8 models with a 68 mm (2.677 in) bore across 1 bearing type, outside diameters from 82 to 85 mm. Tables are grouped by type; open a model for full specs and equivalents.

8 models 82–85 mm OD range 2 brands

Needle Roller Bearings (8)

Model Series d (mm) D (mm) B (mm) Brand Seal Clearance C (kN)
NK68-25 NK 68 82 25 SKF open CN 44
NK68-25-XL nk 68 82 25 FAG open CN 49.5
NK68-35 NK 68 82 35 SKF open CN 60.5
NK68-35-XL nk 68 82 35 FAG open CN 70
RNA4912 RNA-49 68 85 25 SKF open CN 60.5
RNA4912-XL rna49 68 85 25 FAG open CN 68
RNA6912 RNA-69 68 85 45 SKF open CN 93.5
RNA6912-ZW-XL rna69 68 85 45 FAG open CN 106

Selecting a 68 mm bore bearing

The bore fixes the shaft, not the bearing capacity. At 68 mm the catalog spans 82–85 mm outside diameter: the light sections suit compact housings and moderate duty, while the larger ODs use bigger rolling elements and carry substantially more load. Select first by the required dynamic load rating C for the calculated L10 life, then by available radial space.

For a rotating inner ring a k5 shaft seat with an H7 housing is the usual starting point; an interference fit plus thermal growth consumes internal clearance, so C3 is the common industrial default rather than CN. Sealed variants (-2RS, -ZZ) trade a small amount of speed for contamination protection and maintenance-free operation — compare the sealed and open versions of the same envelope before substituting one for the other.

Frequently asked questions

What bearings have a 68 mm bore?

This index lists 8 verified bearing models with a 68 mm (2.677 in) bore across 1 bearing type, from 82 to 85 mm outside diameter. Open any model for the full specification table, seal/clearance options and graded cross references.

How do I choose between the 82–85 mm OD options for a 68 mm shaft?

On a fixed 68 mm bore, a smaller outside diameter means a lighter section for limited housing space and moderate load; a larger OD with a wider ring carries more radial and axial load and lasts longer at the same duty. Compare the C dynamic load rating in each model table, then match seal type, internal clearance (CN/C3/C4) and precision class to the actual mounting and operating temperature.

What shaft fit and bore code apply to 68 mm bearings?

A 68 mm bore on a rotating inner ring normally uses a k5 shaft seat with an H7 housing bore (verify against the catalogue for heavy or stationary-ring duty). Bore diameters below 20 mm follow the 10/12/15/17 mm exception table rather than code × 5.