NKIS30-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 NKIS30-XL model number is decoded

envelope 30×52×22 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 41.5 kN and C0 50 kN at the 30 mm seat; the C/C0 ratio of 0.83 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 8.8 kN, the limiting speed 11,700 r/min and the thermal reference speed 6,400 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 1.38 kN/mm and per millimetre of width 1.89 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 184 g, just 0.16 g per mm² of projected 52×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty NKIS30-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 41.5 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 11,700 r/min limit. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 52 mm outside diameter and 41.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 30 mm seat, and in motorcycle and light-vehicle transmissions the 184 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 22 mm width and the published 50 kN static rating. 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. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.