NK47-30-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 NK47-30-XL model number is decoded

envelope 47×57×30 mm: 47 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 94 kN at the 47 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 57 mm outside diameter the fatigue load limit Cur is 17.8 kN, the limiting speed 9,800 r/min and the thermal reference speed 5,800 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 1.03 kN/mm and per millimetre of width 1.62 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 142 g, just 0.08 g per mm² of projected 57×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 47 mm bore marks the medium range: mounting forces and fits become critical, and the 142 g mass calls for proper induction or press tooling rather than hand fitting With Cur 17.8 kN and a 9,800 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 5.0 mm section makes the 142 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting X-life status (-XL) indicates the current Schaeffler premium execution at 47 mm bore; the 94 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 57 mm outside diameter and 48.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 47 mm seat, and in motorcycle and light-vehicle transmissions the 142 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 30 mm width and the published 94 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. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.

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.
• Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.