NK29-30-XL bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the NK29-30-XL model number is decoded

envelope 29×38×30 mm: 29 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 29 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 10.7 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.28 kN/mm and per millimetre of width 1.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 84.3 g, just 0.07 g per mm² of projected 38×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 29 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The hardness requirement is unforgiving: below about 58 HRC the 29 mm journal brinels under the 57 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 29×38×30 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 38 mm outside diameter and 37 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 29 mm seat, and in planetary gear bearings the 84.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 57 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.