NKI25-30-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 NKI25-30-XL model number is decoded

envelope 25×38×30 mm: 25 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 37 kN and C0 57 kN at the 25 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 8,200 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 1.48 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 124 g, just 0.11 g per mm² of projected 38×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This is the choice for OEM production on soft shafts: machine the 25 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 57 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 37 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 38 mm outside diameter and 37 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 25 mm seat, and in gearbox selector and change linkages the 124 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 57 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• 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.