NKIS45-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 NKIS45-XL model number is decoded

envelope 45×72×22 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 13.5 mm radial section packed with small-diameter needle rollers C is 51 kN and C0 74 kN at the 45 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 13 kN, the limiting speed 8,200 r/min and the thermal reference speed 4,600 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 1.13 kN/mm and per millimetre of width 2.32 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 336 g, just 0.21 g per mm² of projected 72×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 45 mm bore marks the medium range: mounting forces and fits become critical, and the 336 g mass calls for proper induction or press tooling rather than hand fitting The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 74 kN C0 rating still assumes full rigid support under both rings The 13.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 13 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 72 mm outside diameter and 51 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 45 mm seat, and in two-stroke and compressor piston pins the 336 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 74 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• 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.