NA6903-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 NA6903-XL model number is decoded

envelope 17×30×23 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 21.1 kN and C0 29 kN at the 17 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 5.2 kN, the limiting speed 20,000 r/min and the thermal reference speed 9,800 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 1.24 kN/mm and per millimetre of width 0.92 kN/mm — the reason 23 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 72 g, just 0.10 g per mm² of projected 30×23 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 17 mm bore this size balances the 30 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range This is the choice for OEM production on soft shafts: machine the 17 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Cur 5.2 kN, limiting speed 20,000 r/min, reference speed 9,800 r/min — the inner ring adds a few grams (total 72 g) but removes the hardening requirement 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 17×30×23 mm envelope. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 30 mm outside diameter and 21.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 17 mm seat, and in hydraulic and pneumatic pump eccentrics the 72 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 23 mm width and the published 29 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
• 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.