NKS40-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 NKS40-XL model number is decoded

envelope 40×55×22 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 42.5 kN and C0 54 kN at the 40 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.4 kN, the limiting speed 10,900 r/min and the thermal reference speed 6,600 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 1.06 kN/mm and per millimetre of width 1.93 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 129 g, just 0.11 g per mm² of projected 55×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 129 g mass calls for proper induction or press tooling rather than hand fitting Omitting the inner ring frees radial space — at a 40 mm shaft the outer diameter is only 55 mm and the width 22 mm, yet C is 42.5 kN Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 54 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 55 mm outside diameter and 42.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 40 mm seat, and in hydraulic and pneumatic pump eccentrics the 129 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 22 mm width and the published 54 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. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.

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.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.