NK75-25-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 NK75-25-XL model number is decoded

envelope 75×92×25 mm: 75 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 61 kN and C0 104 kN at the 75 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 92 mm outside diameter the fatigue load limit Cur is 18.5 kN, the limiting speed 6,100 r/min and the thermal reference speed 4,050 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 0.81 kN/mm and per millimetre of width 2.44 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 315 g, just 0.14 g per mm² of projected 92×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 92 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,100 r/min With Cur 18.5 kN and a 6,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The hardness requirement is unforgiving: below about 58 HRC the 75 mm journal brinels under the 104 kN static rating, and roughness above raceway finish accelerates roller wear X-life status (-XL) indicates the current Schaeffler premium execution at 75 mm bore; the 104 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 92 mm outside diameter and 61 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 75 mm seat, and in connecting-rod small ends the 315 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 25 mm width and the published 104 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.