NAO25X42X16-IS1-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 NAO25X42X16-IS1-XL model number is decoded

envelope 25×42×16 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 33.5 kN at the 25 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 5.6 kN, the limiting speed 14,600 r/min and the thermal reference speed 7,800 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 1.04 kN/mm and per millimetre of width 1.63 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 86 g, just 0.13 g per mm² of projected 42×16 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 The single needle row fills the thin section, with limiting speed 14,600 r/min and reference speed 7,800 r/min Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 8.5 mm section is too thin to compensate for tilted seats -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 26 kN C rating and longer nominal life come without an envelope change. The IS1 groove keeps the flangeless races lubricable from the shaft side despite the compact 8.5 mm section. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 42 mm outside diameter and 26 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 25 mm seat, and in copying and printing machine mechanisms the 86 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 16 mm width and the published 33.5 kN static rating. 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. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

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