NK18-16-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 NK18-16-XL model number is decoded

envelope 18×26×16 mm: 18 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 14.1 kN and C0 16.2 kN at the 18 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 26 mm outside diameter the fatigue load limit Cur is 3.05 kN, the limiting speed 22,100 r/min and the thermal reference speed 14,400 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 0.78 kN/mm and per millimetre of width 0.88 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 24.9 g, just 0.06 g per mm² of projected 26×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 18 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With Cur 3.05 kN and a 22,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 14.1 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 26 mm outside diameter and 14.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 18 mm seat, and in hydraulic and pneumatic pump eccentrics the 24.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 16 mm width and the published 16.2 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. 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

• Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.
• 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.